CHEMICALS AND CHEMICALS AND CHEMICAL CHANGECHEMICAL CHANGE

Chapter 5.1 Chapter 5.1 BLM 5.1a, 5.1bBLM 5.1a, 5.1b

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Chemicals and chemical Chemicals and chemical ChangeChange

CHEMISTRYCHEMISTRY – is the study of matter, – is the study of matter, its changes and its propertiesits changes and its properties

MATTERMATTER – is anything that has mass – is anything that has mass and takes up spaceand takes up space

ATOMATOM – the smallest unit of matter – the smallest unit of matter

Physical property:Physical property:

Physical characteristics of the substance – Physical characteristics of the substance – observed by senses.observed by senses.

Ex. color, density, hardness, etc. Ex. color, density, hardness, etc.

Chemical properties:Chemical properties:

Properties that describe how a substance Properties that describe how a substance changes into a completely different changes into a completely different substance.substance.

Ex. Flammability and corrosion/oxidation Ex. Flammability and corrosion/oxidation

HANDOUT 5.1aHANDOUT 5.1aUse the following labels and pages 172 – Use the following labels and pages 172 –

173 to complete the handout173 to complete the handoutChemical changes, Chemical changes, pure substances pure substances

(x2)(x2)

C, O, HC, O, H22O, OO, O22 Heterogeneous mixtures, Heterogeneous mixtures, elements, elements, atoms (x2), atoms (x2), NaCl, NaCl, chemical formulas, chemical formulas, chemical symbols,chemical symbols,physical changes, physical changes, solutions, solutions, molecules, molecules, compoundscompounds

HeterogeneousMixture

PureSubstance

PhysicalChanges

Solutions

Elements Compounds

ChemicalSymbols

Atoms

MoleculesChemicalFormulas

PureSubstance

C O

O2

NaClH2O

ChemicalChanges

Atoms

PHYSICAL CHANGEPHYSICAL CHANGE – a change in a – a change in a substance which does not produce substance which does not produce a new substance.a new substance.

EXAMPLE:EXAMPLE: melting ice melting ice

CHEMICAL CHANGECHEMICAL CHANGE – a change in – a change in a substance which does produce a a substance which does produce a new substance.new substance.

EXAMPLEEXAMPLE: match burning: match burning

HANDOUT 5.1bHANDOUT 5.1bUse the following labels and pages 173 – Use the following labels and pages 173 –

174 to complete the handout174 to complete the handoutRusting/corrosion, Rusting/corrosion, difficult to difficult to

reverse, reverse, water vapour, water vapour, turns cloudy, turns cloudy, new colour, new colour, reactants, reactants, pops, pops, turns pink, turns pink, oxygen (x2), oxygen (x2), products, products, precipitate, precipitate, carbon dioxide, carbon dioxide, bursts into flames, bursts into flames, heat or light, heat or light, hydrogenhydrogen

Reactants

Products

Corrosionor Rusting

OxygenTough

to reverseEnergy

Given offPrecipitate

forms

H2 O2 H2OCO2

Pops Bursts intoFlames

TurnsPink

TurnsCloudy

Colour

Change

CLASS/HOMEWORK CLASS/HOMEWORK QUESTIONSQUESTIONS

Page 175Page 175 QUESTIONS: #1-2,4-7QUESTIONS: #1-2,4-7

SOLUTIONS TO HOMEWORK SOLUTIONS TO HOMEWORK QUESTIONSQUESTIONS

Q1 – classify each of the following as a Q1 – classify each of the following as a pure substance or a mixturepure substance or a mixture

A) soapy water A) soapy water MIXTUREMIXTURE

B) hydrogen gas B) hydrogen gas PURE SUBSTANCEPURE SUBSTANCE

C) sodium chloride C) sodium chloride PURE SUBSTANCEPURE SUBSTANCE

QUESTIONQUESTION 22

Classify each of the following as an element Classify each of the following as an element or a compound.or a compound.

A) hydrogen A) hydrogen ELEMENTELEMENT

B) potassium carbonate B) potassium carbonate COMPOUNDCOMPOUND

C) water C) water COMPOUNDCOMPOUND

D) Mg D) Mg ELEMENTELEMENT

QUESTION 4QUESTION 4

Classify each of the following as a physical Classify each of the following as a physical property or a chemical property.property or a chemical property.

A) Gasoline is a clear pink solutionA) Gasoline is a clear pink solutionPHYSICAL PROPERTYPHYSICAL PROPERTY

B) Gasoline burns in airB) Gasoline burns in airCHEMICAL PROPERTYCHEMICAL PROPERTY

C) Water boils at 110C) Water boils at 11000C. C. PHYSICAL PROPERTYPHYSICAL PROPERTY

D) electric current can split water into D) electric current can split water into hydrogen and oxygen gases hydrogen and oxygen gases CHEMICAL PROPERTYCHEMICAL PROPERTY

QUESTION 5QUESTION 5

When aluminum metal is added to When aluminum metal is added to hydrobromic acid, hydrogen gas and hydrobromic acid, hydrogen gas and an aluminum bromide solution are an aluminum bromide solution are formed.formed.

A) What kind of change has occurred?A) What kind of change has occurred?

Chemical, bubbles formed, new Chemical, bubbles formed, new substance madesubstance made

QUESTION 5QUESTION 5

When aluminum metal is added to When aluminum metal is added to hydrobromic acid, hydrogen gas and an hydrobromic acid, hydrogen gas and an aluminum bromide solution are formedaluminum bromide solution are formed

B) Which substances are the reactants and B) Which substances are the reactants and which are the products?which are the products?

Reactants – Aluminum and AcidReactants – Aluminum and Acid

Products – Hydrogen + Aluminum BromideProducts – Hydrogen + Aluminum Bromide

QUESTION 6QUESTION 6

Describe the chemical tests that can be Describe the chemical tests that can be used to identify the following gases.used to identify the following gases.

A) hydrogen A) hydrogen

a flaming wooden splint causes a a flaming wooden splint causes a “pop”“pop”

B) Oxygen B) Oxygen

a glowing wooden splint relights a glowing wooden splint relights (bursts into flame)(bursts into flame)

QUESTION 6QUESTION 6

C) Carbon DioxideC) Carbon Dioxide

A burning wooden splint extinguishes, A burning wooden splint extinguishes, OR when the gas is bubbled through OR when the gas is bubbled through limewater, the limewater changes limewater, the limewater changes from a clear, colourless solution to a from a clear, colourless solution to a cloudy white liquid (a precipitate is cloudy white liquid (a precipitate is formed)formed)

QUESTION 6QUESTION 6

d) Water Vapourd) Water Vapour

Changes the colour of cobalt chloride Changes the colour of cobalt chloride test paper from blue to pinktest paper from blue to pink

QUESTION 7QUESTION 7

When sodium carbonate is added to When sodium carbonate is added to water, the sodium carbonate water, the sodium carbonate dissolves. dissolves.

When hydrochloric acid is added to the When hydrochloric acid is added to the solution, the solution fizzes. What solution, the solution fizzes. What kinds of changes have occurred?kinds of changes have occurred?

QUESTION 7 - ANSWERQUESTION 7 - ANSWER

When sodium carbonate dissolves in When sodium carbonate dissolves in water it is a physical changewater it is a physical change

A chemical change happens when gas A chemical change happens when gas is formed after hydrochloric acid is is formed after hydrochloric acid is added ( fizz / Bubbles )added ( fizz / Bubbles )