subject chemistry 1. basic terms, physical and chemical...

Gymnázium, Brno, Slovanské nám. 7, WORKBOOK - Chemistry

I N V E S T I C E D O R O Z V O J E V Z D Ě L Á V Á N Í

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WORKBOOK

http://agb.gymnaslo.cz

Subject: Chemistry Class: 1.X

Topics: 1. Basic terms, physical and chemical properties of substances 2. Mixtures 3. Radioactivity, structure of atom 4. Basic calculations in chemistry 5. Fractions 6. Chemical bonding 7. Acids and bases 8. The pH scale



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VOCABULARY

Topic 1: Basic terms in chemistry atom – the smallest particle of a given type of matter atomic mass unit – one-twelfth the mass of a carbon atomic number – the number of protons in the nucleus of an atom of an element chemical change (reaction) – the change of one or more substances into other

substances chemical property – a property that can be observed only when there is a change in

the composition of a substance chemistry – the science that investigates and explains the structure and properties of

matter compound – a chemical combination of two or more different elements joined

together in a fixed proportion density – the amount of matter (mass) in a given unit volume element – a substance that cannot be broken down into simpler substances endothermic – chemical reaction that absorbs energy energy – the capacity to do work exothermic – chemical reaction that gives off energy experiment – a set of controlled observations that test the hypothesis formula - a combination of chemical symbols that show what elements make up a

compound and the number of atoms of each element isotope – any of two or more atoms of an element that are chemically alike but have

different masses law of conservation of mass – in a chemical change, matter is neither created nor

destroyed mass – the measure of the amount of matter an object contains mass number – the sum of the neutrons and protons in the nucleus of an atom matter – anything that takes up space and has mass mixture – a combination of two or more substances in which the basic identity of

each substance is not changed molecule – the smallest particle of a compound that possesses the chemical

properties of the compound; a definite, distinct, electrically neutral group of bonded atoms

physical change – change in matter where its identity does not change physical property – a characteristic of matter that is exhibited without a change of

identity property – the characteristics of matter; how it behaves qualitative – an observation made without measurement quantitative – an observation made with measurement solute – the substance that is being dissolved when making a solution solution – a mixture that is the same throughout, or homogeneous



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solvent – the substance that dissolves the solute when making a solution substance – matter with the same fixed composition and properties technology – the practical use of scientific information theory – an explanation supported by many experiments; is still subject to new

experimental data, can be modified, and is considered valid it if can be used to make predictions that are proven true

weight – a measure of an amount of matter and also the effect of Earth’s gravitational pull on that matter

Topic 2: Mixtures alloy – a solid solution containing different metals, and sometimes nonmetalic

substances aqueous solution – a solution in which the solvent is water chromatography – a technique that is used to separate the components of a mixture

based on the tendency of each component to travel or be drawn across the surface of another material

colloid – a mixture that contains particles that are evenly distributed through a dispersing medium and do not settle out over time; a dispersion of tiny particles with diameters between 1 nm and 1 µm in a gas, liquid, or solid (example milk)

crystallization – a separation technique that produces pure solid particles of a substance from a solution that contains the dissolved substance

dissociation – the process by which the charged particles in an ionic solid separate from one another, primarily when going into solution

distillation – a technique that can be used to physically separate most homogeneous mixtures based on the differences in the boiling points of the substances involved

filtration – a technique that uses a porous barrier to separate a solid from a liquid gas – a form of matter that flows to conform to the shape of its container, fills the

container’s entire volume, and is easily compressed heat of solution – the heat taken in or released in the dissolving process heterogeneous mixture – one that does not have a uniform composition and in

which the individual substances remain distinct homogeneous mixture – one that has a uniform composition throughout and always

has a single phase; also called a solution liquid – a form of matter that flows, has constant volume, and takes the shape of its

container mixture – a combination of two or more substances in which the basic identity of

each substance is not changed phase change – a transition of matter from one state to another saturated solution – a solution that holds the maximum amount of solute under the

given conditions solid – a form of matter that has its own definite shape and volume, is

incompressible, and expands only slightly when heated



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solute – the substance that is being dissolved when making a solution solution – a mixture that is the same throughout, or homogeneous solvent – the substance that dissolves the solute when making a solution states o matter – the physical forms in which all matter naturally exists on Earth-

most commonly as a solid, a liquid, or a gas supersaturated solution – a solution containing more solute than the usual

maximum; they are unstable unsaturated solution – a solution in which the amount of solute dissolved is less than

the maximum that could be dissolved

Topic 3: Basic Calculations atomic mass constant (mu) – one-twelfth the mass of one atom of carbon-12 atomic weight – the mass per mole of atoms of an element Avogadro’s constant – the number of objects per mole of objects (NA = 6,02214 x

1023 mol-1) Avogadro’s number – the number of objects in one mole of objects (that is, the

dimensionless number 6,02214 x 1023) empirical formula – a formula that shows the smallest whole-number mole ratio of

the elements of a compound, and may or may not be the same as the actual molecular formula

excess reactant – a reactant that remains after a chemical reaction stops hydrate – a compound that has a specific number of water molecules bound to its

atoms ideal gas law – the equation that expresses exactly how pressure P, volume V,

temperature T, and the number of particles n of a gas are related; pV=nRT molar mass – the mass in grams of one mole of any pure substance molar volume – for a gas, the volume that one mole occupies at 0,00°C and 1,00 atm

pressure mole – the SI unit of chemical amount; the mole is the amount of substance that

contains as many specified entities as there are atoms in exactly 12 g of carbon-12 molecular formula – a formula that specifies the actual number of atoms of each

element in one molecule or formula unit of the substance molecular mass – the mass in atomic mass units of one molecule of a covalent

compound molecular weight – the mass per mole of molecules of a compound percent composition – the percent by mass of each element in a compound percent yield – the ratio of actual yield (from an experiment) to theoretical yield

(from stoichiometric calculations) expressed as a percent stoichiometry – the study of relationships between measureable quantities, such as

mass and volume, and the number of atoms in chemicals reactions theoretical yield – in a chemical reaction, the maximum amount of product that can

be produced from a given amount of reactant



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Topic 4: Structure of atom, chemical elements and periodic table of the elements (PTE) actinide – any of the second series of inner transition elements with atomic numbers

from 90 to 103; all are radioactive alkali metal – any element from Group 1: lithium, sodium, potassium, rubidium,

cesium, francium alkaline earth metal – any element Group 2: beryllium, magnesium, calcium,

strontium, barium alpha particle – a particle with two protons and two neutrons, with a 2 charge; is

equivalent to a helium-4 nucleus, and is emitted during radioactive decay alpha radiation – radiation that is made up of alpha particles; is deflected toward a

negatively charged plate when radiation from a radioactive source is directed between two electrically charged plates

atom – (1) the smallest particle of an element that has the chemical properties of that element; (2) an electrically neutral species consisting of a nucleus and its surrounding electrons

atomic mass constant (mu) – one-twelfth the mass of one atom of carbon-12 atomic number – the number of protons in the nucleus of an atom of an element atomic theory – the idea that matter is made up of fundamental particles called

atoms aufbau principle – states that each electron occupies the lowest energy orbital

available beta particle – a high-speed electron with a 1-charge that is emitted during

radioactive decay beta radiation – radiation that is made up of beta particles; is deflected toward a

positively charged plate when radiation from a radioactive source is directed between two electrically charged plates

cathode ray – a ray of radiation that originates from the cathode and travels to anode of a cathode-ray tube

Daltons atomic theory – Daltons theory proposed in 1803 stating that matter is composed of extremely small particles called atoms; atoms are invisible and indestructible; atoms of a given element are identical in size, mass, and chemical properties; atoms of a specific element are different from those of another element; different atoms combine in simple whole-number ratios to form compounds

de Broglie equation – predicts that all moving particles have wave characteristic and relates each particle’s wavelength to its frequency, its mass, and Planck’s constant

deuterium – the hydrogen isotope with a mass number of 2 electromagnetic radiation – a form of energy exhibiting wavelike behaviour as it

travels through space; can be described by wavelength, frequency, amplitude, and speed and includes visible light, microwaves, X rays, and radio waves

electromagnetic spectrum – the whole range of electromagnetic radiation electron – negatively-charged particle



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electron cloud – the space around the nucleus of an atom where the atoms electrons are found

electron configuration – the most stable arrangement of electrons in sublevels and orbitals

electron-dot structure – consists of an element’s symbol, representing the atomic nucleus and inner-level electrons, that is surrounded by dots, representing the atom’s valence electrons

electronegativity – indicates the relative ability of an element’s atoms to attract electrons in a chemical bond

emission spectrum – the spectrum of light released from excited atoms of an element

energy level – the regions of space in which electrons can move about the nucleus of an atom

experiment – a set of controlled observations that test a hypothesis gamma rays – high-energy radiation that has no electrical charge and no mass; is not

deflected by electric or magnetic fields, usually accompanies alpha and beta radiation, and accounts for most of the energy lost during radioactive decay

ground state – the lowest allowable energy state of an atom group – the elements in a vertical column of the periodic table half-life – the time it takes for half of a given radioactive isotope to decay (into a

different isotope or element) halogen – any element from Group 17: fluorine, chlorine, bromine, iodine, astatine Heisenberg uncertainly principle – the principle that is impossible to accurately

measure both the position and energy of an electron at the same time Hund’s rule – states that single electrons with the same spin must occupy each equal-

energy orbital before additional electrons with opposite spins can occupy the same orbitals

hypothesis – a prediction that can be tested to explain observations inner transition element – one of the elements in the two rows of elements below

the main body of the periodic table; the lanthanides and the actinides ion – an atom or bonded group of atoms with a positive or negative charge ionization energy – the energy required to remove an electron from a gaseous atom;

generally increases in moving from left-to-right across a period and decreases in moving down a group

isotope – any of two or more atoms of an element that are chemically alike but have different masses; isotopes = atoms of the same element with different numbers of neutrons

lanthanide – one of the first series of inner transition elements with atomic numbers 58 to 71

law of definite proportions – the principle that the elements that comprise a compound are always in a certain proportion by mass

Lewis dot diagram – a diagram where dots or other small symbols are placed around the chemical symbol of an element to illustrate the valence electrons



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mass number – the sum of the neutrons and protons in the nucleus of an atom metal – an element that has luster, conducts heat and electricity, and usually bends

without breaking metalloid – an element with some physical and chemical properties of metals and

other properties of non-metals neutron – a subatomic particle with a mass equal to a proton but with no electrical

charge noble gas – an element from Group 18 that has a full compliment of valence

electrons and as such is unreactive non-metal – an element that in general does not conduct electricity, is a poor

conductor of heat, and is brittle when solid. Many are gases at room temperature. nuclear equation – a type of equation that shows the atomic number and mass

number of the particles involved nuclear fission – the process in which an atomic nucleus splits into two or more large

fragments nuclear fusion – the process in which two or more nuclei combine to form a larger

nucleus nuclear reaction – a reaction that involves a change in the nucleus of an atom nuclear reactor – the device used to extract energy from a radioactive fuel nucleus – the small, dense, positively charged central core of an atom octet rule – states that atoms lose, gain, or share electrons in order to acquire a full

set of eight valence electrons (the stable electron configuration of a noble gas) orbital – the space in which there is a high probability of finding an electron Pauli exclusion principle – states that a maximum of two electrons can occupy a

single atomic orbital but only if the electrons have opposite spins period – a horizontal row in the periodic table periodic law – the statement that the physical and chemical properties of the

elements repeat in a regular pattern when they are arranged in order of increasing atomic number

periodicity – the tendency to recur at regular intervals principal energy levels – the major energy levels of an atom principal quantum number – n, which the quantum mechanical model assigns to

indicate the relative sizes and energies of atomic orbitals proton – a positively charged subatomic particle quantum – the minimum amount of energy that can be gained or lost by an atom quantum mechanical model of the atom – an atomic model in which electrons are

treated as waves; also called the wave mechanical model of the atom quantum number – the number assigned to each orbit of an electron radiation – the rays and particles - - alpha and beta particles and gamma rays -- that

are emitted by radioactive materials radioactive decay – a spontaneous process in which unstable nuclei lose energy by

emitting radiation radioactivity – the process in which some substances spontaneously emit radiation



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semiconductor – an element that does not conduct electricity as well as a metal, but that does conduct slightly better than a non-metal

sublevel – the small energy division in a given energy level transition element – any of the elements in Groups 3 through 12 of the periodic

table, all of which are metals transition metal – the elements in groups 3-12 that are contained in the d-block of

the periodic table and, with some exceptions, is characterized by a filled outermost s orbital of energy level n, and filled or partially filled d orbitals of energy level n-1

tritium – the hydrogen isotope with a mass number of 3 valence electron – an electron in the outermost energy level of an atom; determine

the chemical properties of an element

Topic 5: Structure of the molecules, chemical bonding, chemical reactions, kinetics, thermochemistry activation energy – the amount of energy the particles in a reaction must have when

they collide for the reaction occur allotrope – any of two or more molecules of a single element that have different

crystalline or molecular structures amorphous solid – a substance with a haphazard, disjointed, and incomplete crystal

lattice anhydrous – a compound in which all water has been removed, usually by heating anion – a negative ion anode – the electrode that takes electrons away from the reacting ions or atoms in

solution binary compound – a compound that contains only two elements catalyst – a substance that speeds up the rate of a reaction without being used up

itself or permanently changed cathode – the electrode that brings electrons to the reacting ions or atoms in

solution cation – a positive ion coefficient – a number placed in front of the parts of a chemical equation to indicate

how many are involved; always a positive whole number combustion – term for a reaction in which a substance rapidly combines with oxygen

to form one or more oxides concentration – the amount of a substance present in a unit volume covalent bond – the attraction of two atoms for a shared pair of electrons covalent compound – a compound whose atoms are held together by covalent bonds crystal – a regular, repeating arrangement of atoms, ions, or molecules in three

dimension decomposition – the name applied to a reaction where a compound breaks down

into two or more simpler substances



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deliquescent – a substance that takes up enough water from the air that it dissolves completely to a liquid solution

double bond – a bond formed by the sharing of two pairs of electrons between two atoms

double displacement – a type of reaction where the positive and negative portions of two ionic compounds are interchanged; at least one product must be water or a precipitate

ductile – property of metal that means it can easily be drawn into a wire dynamic equilibrium – term describing a system in which opposite reactions are

taking place at the same rate electric current – the flow of electrons in a particular direction electrolysis – the process in which electrical energy causes a nonspontaneous

chemical reaction to occur electrolyte – any compound that conduct electricity when melted or dissolved in

water electrolytic cell – the electrochemical cell in which electrolysis takes place electronegativity – the measure of the ability of an atom in a bond to attract

electrons entropy – term used to describe and measure the degree of disorder in a process enzyme – a biological catalyst equilibrium – term for a system where no net change occurs in the amount of

reactants or products formula unit – the simplest ratio of ions in a compound heat – the energy transferred from an object at high temperature to an object at

lower temperature hydrate – a compound in which there is a specific ratio of water to ionic compound hygroscopic – a substance that absorbs water molecules from the air to become a

hydrate inhibitor – a substance that shows down a reaction insoluble – term describing a compound that does not dissolve in a liquid interparticle forces – the forces between the particles that make up a substance ion – an atom or group of combined atoms that has a charge because of the loss or

gain of electrons ionic bond – the strong attractive force between ions of opposite charge ionic compound – a compound comprised of ions Le Chateliers principle – states that if a stress is applied to a system at equilibrium,

the system shifts in the direction that relieves the stress limiting reactant – the reactant of which there is not enough; when it is used up, the

reaction stops and no new product is formed low of conservation of energy – statement that energy is neither created nor

destroyed in a chemical change, but is simply changed from one form to another malleable – property of a metal meaning it can be pounded or rolled into thin sheets



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metallic bond – the bond that results when metal atoms release their valence electrons to a pool of electrons shared by all the metal atoms

molecular element – a molecule formed when atoms of the same element bond together

molecular substance – a substance that has atoms held together by covalent rather than ionic bonds

molecule – an uncharged group of two or more atoms held together by covalent bonds

noble gas configuration – the state of atom achieved by having the same valence electron configuration as a noble gas atom; the most stable configuration

octet rule – states that atoms lose, gain, or share electrons in order to acquire a full set of eight valence electrons (the stable electron configuration of a noble gas)

oxidation – a reaction in which an element loses electrons oxidation number – the charge on an ion or an element; can be positive or negative oxidation-reduction reaction – a reaction characterized by the transfer of electrons

from one atom or ion to another. Also known as a redox reaction oxidizing agent – the substance that gains electrons in a redox reaction. It is the

substance that is reduced polar covalent bond – a bond where the electrons are shared unequally; there is

some degree of ionic character to this type of bond polar molecule – a molecule that has a positive pole and a negative pole because of

the arrangement of the polar bonds; also called dipole polyatomic ion – an ion that consists of two or more different elements potential difference – the difference in electron pressure at the cathode (low) and at

the anode (high) in an electrochemical cell product – a new substance formed when reactants undergo chemical change reactant – a substance that undergoes a reaction reducing agent – the substance that loses electrons in a redox reaction. It is the

substance that is oxidized reduction – a reaction in which an element gains one or more electrons single displacement – a type of reaction where one element takes place of another in

a compound soluble – term describing a substance that dissolves in a liquid synthesis – the name applied to a reaction in which two or more substances combine

to form a single product triple bond – a bond formed by sharing three pairs of electrons between two atoms voltage – an electrical potential difference, expressed in units of volts voltaic cell – a type of electrochemical cell that converts chemical energy into

electrical energy by a spontaneous redox reaction

Topic 6: Nomenclature of inorganic compounds anion – a negative ion



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binary compound – a compound that contains only two elements cation – a positive ion compound – a chemical combination of two or more different elements joined

together in a fixed proportion covalent compound – a compound whose atoms are held together by covalent bonds electronegativity – the measure of the ability of an atom in a bond to attract

electrons formula - a combination of chemical symbols that show what elements make up a

compound and the number of atoms of each element hydrate – a compound in which there is a specific ratio of water to ionic compound ion – an atom or group of combined atoms that has a charge because of the loss or

gain of electrons ionic compound – a compound comprised of ions molecular element – a molecule formed when atoms of the same element bond

together molecule – an uncharged group of two or more atoms held together by covalent

bonds oxidation number – the charge on an ion or an element; can be positive or negative polyatomic ion – an ion that consists of two or more different elements



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Fig. 1. The Periodic Table of the Elements (source www.wikipedia.org)



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KEY TERMS

chemistry

analytical chemistry

general chemistry

inorganic chemistry

organic chemistry

physical chemistry

geochemistry

biochemistry

chemist

biochemist

science

scientist

scientific

biology

physics

physical

humanities

atom

electron

neutron

proton

electron shell

nucleus of atom

chemical element (element)

molecule

compound

substance

crystal

mole

energy

chemical process(es)

chemical reaction

chemical formula (formula)

equation

structure

ion

cation

anion

salt



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acid

base

acidity

basicity

pressure

temperature

density

matter

solid

liquid

gas

aqua

physical property

chemical property

chemical bond

laboratory

filtration

destillation

sublimation

separation

oxidation

reduction

isotope

law

law of conservation of energy

law of conservation of mass

mass

matter

metal

nonmetal

metalloid

theory

hypotesis

symbol

solution

the periodic table of the chemical elements (PTE)

group

poriod

nature



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natural

environment

burning

mixture

heterogenous mixture

homogenous mixture

emulsion

suspension

aerosol

soluble

pure

composition

sample

problem

volume

quantity

interaction

observation

observe

measure

measurement

unit

neutral

discovery

development

atomic number

mass number

neutron number

nomenclature



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1. BASIC TERMS, PHYSICAL AND CHEMICAL PROPERTIES

1. Fill this table. Do not forget about the units!!! Table of the physical and chemical properties of pure (distilled) water.

property unit value

molecular formula

molar mass

density

melting point

boiling point

states of matter

pH

crystal structure of ice

2. What does the bowling point depend on?............................................................................. 3. What boiling point of pure water will be by the sea level? ……………………………….. 4. What boiling point of pure water will be to the summit of Mount Everest?........................ 5. HCl, H2, H2SO4, HCOOH, F2, He, FeCl3, KMnO4, H, Br+, H2O, K4[Fe(CN)6], S8

a) underline compounds

b) which of them are molecules …………………………………………………………

c) which of them are homogenous molecules ………………………………………….

d) which of them are heterogenous molecules ………………………………………….

2. MIXTURES

Think about these statements and choose the right answer:

1. Mixtures are always combinations of the same compounds that are at different states. a) true b) false



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2. You can separate all mixtures by filtration. a) true b) false 3. Would it be possible to have a mixture made of all carbon atoms and compounds with only carbon atoms? a) true b) false 4. All mixtures are defined as "heterogeneous." a) true b) false 5. Mixtures are generally separated by what methods? a) chemicals b) physicals 6. Only specific compounds can be combined to form mixtures. a) true b) false 7. All solutions are mixtures, but not all mixtures are solutions. a) true b) false 8. Which of these is not a mixture? a) solution b) alloy c) amalgam d) they are all mixtures 9. Which of these is not a mixture? a) oil and water b) sand and water c) diet soda d) all are mixtures 10. A solution is defined as a mixture that is... a) homologous b) heterogenous c) homogenous

3. RADIOACTIVITY, STRUCTURE OF ATOM Reading:

What is Radioactivity?

Radioactivity is the spontaneous emission of energy from unstable atoms.

Atoms are found in all natural matter. There are stable atoms, which remain the same forever, and unstable atoms, which break down or 'decay' into new atoms. These unstable atoms are said to be 'radioactive', because they emit radioactivity from the nucleus as they decay.



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Radioactive elements, such as uranium, thorium and potassium break down (decay) fairly readily to form lighter atoms. The energy that is released in the process is made up of small, fast-moving particles and high-energy waves. These particles and waves are, of course, invisible. (The level of radioactivity of an element varies according to how stable its atoms are). Other elements with naturally occurring radioactive forms, (isotopes) are carbon, bismuth, radon, and strontium.

Radioactivity is a random process that happens naturally as the isotopes in particular elements decay. The isotopes continue to break down over time. The length of time that is taken for half of the nuclei in an element to decay is called its 'half-life'. A half-life can be very short (milliseconds to hours) or very long (hundreds of thousands of years).

Radiation also arises from nuclear fission. Fission can be spontaneous but is usually initiated in a nuclear reactor. Fission is a radioactive process; it releases energy as the heavy nucleus is split into two.

Radioisotopes are commonly used in medicine, and are produced as a by-product of nuclear energy.

Fig. 2. (www.wikipedia.org)

1. What is the difference in α and 2

4He? 2. Which of the following reactions represent natural radioactive decay and which are artificially induced? a) Bi → Tl + α b) U + n → U + γ c) N + α → O + H 3. Complete the following nuclear equations: a) Pa → U + ................ b) U + .......... → Ba + Kr + 2 n



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4. One-fourth of the radioactive atoms of a certain sample are present 20.0 minutes after the original measurement. How many will be present after another 10.0 minutes? 5. Look up the number of people killed in the Chernobyl nuclear accident. Look up the number of people in the United States in accidents involving drunken drivers in 2006. Look up the number of people which die in one year worldwide as a result of cigarette smoking. Comment on the relative risk of mortality of nuclear accidents as opposed to cigarette smoking and drunken driving. 6. Write detailed electronic configurations for the following: a) S b) C c) P d) Ca e) Zn 7. How many different values of m are permitted for an electron with l = 3 ? 8. How many different orbitals are there in an l = 2 subshell? 9. Write electronic configurations for the following: a) Na+I b) S-II 10. Explain why the helium atom is stable with only two electrons in its outermost shell? 11. How many unpaired electrons are there in a) a carbon atom and b) a fluorine atom? a) b) 12. Write the electronic configuration for Cs using the shortened notation.

4. BASIC CALCULATIONS IN CHEMISTRY

1. Calculate relative atomic masses of: (a) hydrogen (real weight of hydrogen is 1, 67348 . 10-27 kg) (b) carbon (real weight of carbon is 1, 99 . 10-26 kg) (c) fluorine (real weight of fluorine is 3,15 . 10-26 kg) 2. Calculate relative molecular masses of: (a) water (b) potassium sulphate Na2SO4 (c) thallium hydroxide TlOH (d) glucose C6H12O6



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3. Calculate the number of moles in (a) 20 g of phosphorus P (b) 20 g of phosphorus P4 (c) 300 g of potassium bromide KBr (d) 48 g of sulphur S8 4. Let's have 2,00 mol of carbon dioxide CO2 . Calculate (use the normal conditions): (a) number of molecules of carbon dioxide (b) weight of this amount of CO2 (c) volume of this amount of CO2 5. How many molecules of SO2 (g) is included in 2,5 mol of sulphur dioxide? (use the normal conditions) 6. What volume occupy (use the normal conditions): (a) 2 moles of ammonia NH3? (b) 5 moles of hydrogen chloride HCl? (c) 3,33 moles of carbon monoxide CO? 7. Estimate the mass fraction (in percents) of: (a) carbon in CO2 (b) iron in FeCl3 (c) tin in SnO2 (d) copper in CuSO4 . 5H2O (e) boron in H3BO3 8. How many percents of oxygen is present in ethyleneglycol C2H6O2 (antifreezee substance in cars)? 9. Determine the empirical formulas for these compositions of substances: (a) 18,27% of K, 59,30% of I and 22,43% of O (b) 40,04% of S, 59,96% of O (c) 29,08% of Na, 40,56% of S and 30,36% of O 10. Write the molecular formula of glucose containing 40,00% of C, 6,67% of H (the rest is oxygen) and having molar mass 180 g . mol-1. 11. Determine the molecular formula of vitamin C. Its percet composition is: 40,91% of C, 4,58% of H and 54,51% of O. Molar mass of vitamin C (ascorbic acid) is 176 g . mol-1.



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12. In 700 grams of Mattoni is dissolved 0,716 g of soluble salts. Calculate what part of mineral water form the salts (in %). 13. What is the mass of 7,12 . 1022 NaCl molecules?

5. FRACTIONS - COMPOSITIONS OF MIXTURES 1. What is the mass fraction of KCl in solution containig (a) 30 grams of KCl in 400 grams of water? (b) 30 grams of KCl in 400 grams of the whole solution? 2. We prepared the 3% solution from 3 grams of substance. What mass of solution we prepared? 3. In 700 grams of Mattoni is dissolved 0,716 g of soluble salts. Calculate what part of mineral water form the salts (in %). 4. Let's assume Vincentka mineral water. It contains 0,9% of NaCl. What mass of NaCl you drink in 200 grams (one glass) of this water? 5. You have to prepare one litre of salt solution having density ζ = 1,05 g . cm-3 and containing 23% of salt. How many grams of salt do we have to put into the water? 6. How many grams of water do we need to put to 30 grams of substance, if we need to prepare 30% solution? 7. Let's make 5% solution of solid substance from 400 grams of water. How many grams of the solid substance do we need? 8. Red wine has the volume fraction of ethanol cca 11%. What volume of pure ethanol is present in 700 ml bottle of wine? 9. Plum brandy contains 50 mililitres of absolute ethanol in 84 mililitres of this beverage. What is the volume fraction of ethanol in this plum brandy? 10. We mixed 30 mililitres of methanol with 50 mililitres of water. What is the volume fraction of methanol and water in this mixture? 11. Simplified vodka is the 40% ethanol solution in water. What volume of vodka we must drink, to have 100 ml of absolute ethanol drunken?



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6. CHEMICAL BONDING 1. Let's assume following compounds: POCl3, HCl, F2, BH3, NCl3, OF2, NaF, CsCl, CH4, H2S Decide which of them contain polar bond and which do not. Support your solution with calculation. 2. Define following terms: (a) electronegativity (b) atomic radius (c) electron afinity (d) binding energy (e) length of chemical bond 3. Which of these compounds will be able to interact by intermolecular hydrogen bonds? H2O, H2S, NH3, HCl, CH3NO2, HF, CH3CH2OH, NaCl 4. Using the electron configuration box diagrams, describe the multiplicity of chemical bond in these molecules: Cl2, H2, S2, N2, Ne2 5. By electron configuration diagrams, describe the formation of these molecules (Hint - when the valency is not permitted in ground state, use the excited state of central element): H2O, CH4, NO, NH3, PH3, PF3, LiCl, POCl3, PCl3 6. The dissociation energy of C-H bond is Edis(C - H) = 345 kJ.mol-1. Calculate the energy emitted when methane molecule CH4 is formed. 7. Describe (by electron configuration diagrams) the formation of coordination covalent bond in following molecules: NH4

+, H3O+

8. Enumerate the essentials of metal bond and discuss the inuence of metal bond on properties



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of metals. 9. What is the criterion of determining the polarity of bonds? 10. Describe the electron configuration of ions in following ionic compounds: NaF, KCl, LiF, Na3B, Na2O 11. What is the principle of ionic bond? Describe the formation of ionic bond generally. 12. Explain the principles of van der Waals interactions of following types and give example to each of them (a) ion-ion (b) ion-dipole (c) dipole-dipole (d) dipole-inducted dipole 13. Give the explanation of main diference between σ-bond and π-bond. How many σ -bonds are there in triple bond? How many π -bonds? 14. Try to make a figure of following orbital overlaps. Decide which kind of molecular orbital is generated: (a) p-p overlap (assume all three orientations of p-orbital) (b) s-p overlap (c) s-s overlap 15. Emphasize the partial charges on atoms in following molecules: H2O, CH3Cl, BF3, CH3COOH, ICl 16. Compare the length and strength of classical covalent bond and weak bonding interactions. 17. Decide which of these atoms or molecules are radicals: H, Cl, CH3, NO, F2, Na, B



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7. ACIDS AND BASES

Reading:

ACIDS AND BASES ARE EVERYWHERE

Every liquid you see will probably have either acidic or basic traits. One exception might be distilled water. Distilled water is just water. That's it. The positive and negative ions in distilled water are in equal amounts and cancel each other out. Most water you drink has ions in it. Those ions in solution make something acidic or basic. In your body there are small compounds called amino acids. Those are acids. In fruits there is something called citric acid. That's an acid, too. But what about baking soda? When you put that in water, it creates a basic solution. Vinegar? Acid. Scientists use something called the pH scale to measure how acidic or basic a liquid is. Although there may be many types of ions in a solution, pH focuses on concentrations of hydrogen ions (H+) and hydroxide ions (OH-). The scale goes from values very close to 0 through 14. Distilled water is 7 (right in the middle). Acids are found between a number very close to 0 and 7. Bases are from 7 to 14. Most of the liquids you find every day have a pH near 7. They are either a little below or a little above that mark. When you start looking at the pH of chemicals, the numbers go to the extremes. If you ever go into a chemistry lab, you could find solutions with a pH of 1 and others with a pH of 14. There are also very stong acids with pH values below one such as battery acid. Bases with pH values near 14 include drain cleaner and sodium hydroxide (NaOH). Those chemicals are very dangerous.

NAMES TO KNOW

Here are a couple of definitions you should know: Acid: A solution that has an excess of H+ ions. It comes from the Latin word acidus that means "sharp" or "sour". Base: A solution that has an excess of OH- ions. Another word for base is alkali. Aqueous: A solution that is mainly water. Think about the word aquarium. AQUA means water. Strong Acid: An acid that has a very low pH (0-4). Strong Base: A base that has a very high pH (10-14). Weak Acid: An acid that only partially ionizes in an aqueous solution. That means not every molecule breaks apart. They usually have a pH close to 7 (3-6). Weak Base: A base that only partially ionizes in an aqueous solution. That means not every molecule breaks apart. They usually have a pH close to 7 (8-10). Neutral: A solution that has a pH of 7. It is neither acidic nor basic.



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8. The pH SCALE

Reading: The concentration of hydrogen ions is commonly expressed in terms of the pH scale. Low pH corresponds to high hydrogen ion concentration and vice versa. A substance that when added to water increases the concentration of hydrogen ions(lowers the pH) is called an acid. A substance that reduces the concentration of hydrogen ions(raises the pH) is called a base.Buffers are solutions to resist pH changes when an acid or base is added. Buffers are very important in helping organisms maintain a relatively constant pH.

Fig. 3. The pH Scale (www.wikipedia.org)



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Calculation of pH

1.ACIDS a) pH = - log cHA

b) pH = - log n. cHnA

n is number of H+

2. BASES a) pOH = -log cB

pH = 14 - pOH b) pOH = -log n. cB

pH = 14 – pOH n is number of OH-

Calculate the following problems: 1. Calculate pH of solution of HCl. Molar concentration of solution of HCl is 0,5 mol.dm-3. 2. Calculate pH of solution of H2SO4. Molar concentration of solution of H2SO4 is 0,0006 mol.dm-3. 3. Calculate pH of solution of LiOH. Molar concentration of solution of LiOH is 0,02 mol.dm-3. 4. Calculate pH of solution of Al(OH)3. Molar concentration of solution of Al(OH)3 is 0,1 mol.dm-3. 5. What is the molar concentration and pH of hydrochloric acid in solution that contains 0,5 mol of HCl in 500 cm3 of solution?

subject chemistry 1. basic terms, physical and chemical...

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