•H2O is liquid, but H2S is what?Gas• Which sulfur has needle shaped crystals?Prismatic • Gold paint made from:Copper • Name a reducing agent:Hydrogen sulfide• Name the dehydrating agent: Sulfuric acid • Name a bleaching agent:Sulfur di oxide • A rain coat is made up of what?Polychloroethene• Which element on adding to natural rubber makes it less sticky in hot weather and less hard in cold weather? Sulfur• Which chemical causes Minimata disease?Mercury • The absence of cobalt in minute quantities in human body causes what?Pernicious anemia• Which element can easily form chains?Carbon• Oxygen can accept electron from all elements except what?Fluorine• Which element is used as an antichlor?SO2• Which is the most reactive element in sixth group?Oxygen • Which is the smallest atom in sixth group element? Oxygen• All the oxide which contains two atoms of oxygen in a molecule is called what?Di oxides• Write example for slow chemical reaction:Rusting of ironChange of mill into curd• Which catalyst used in the manufacture of ammonia from nitrogen and hydrogen?Iron• Which substance used as catalyst in the preparation of oxygen from potassium chlorate?Manganese dioxide• Which compound formed when hydrogen peroxide decomposes?Water • Which useable substance formed as a result of collision?Active complexes• Which element can toxic to plants growing in soils that are high acidity?Aluminum• Glass is made out of what?Sand • Which is considered to be an anomalous compound? Water• How would you know that a chemical is pure or not?By checking its melting point

• Which drug is present in cola drinks?Caffeine• Which fuel produce maximum heat per gram burnt?Hydrogen• Which element in radioactive form is used for determining the age of artifacts, relics, bones etc. of the past?Carbon• Which product of living organisms was the first to be made under the laboratory conditions?

Urea• Which drug is present in tobacco?Nicotine• What is the most common natural source for sulfur?Volcanic region • The first scientific definition of a chemical element was made in which book?The Sceptical Chymist• Which element is present in the least amount in a living body?Manganese• Which substance is produced when nitrogen react with hydrogen? Ammonia• Which metal has the density is less than that of water?Sodium• Which catalyst used in the manufacture of sulfuric acid?Vanadium pent oxide • Which metal react with water and forms an alkaline compound?Sodium• Which metal floats on water?Sodium (potassium) • Which theory is used for explaining the changes in reaction rate?Collision theory

1. What is the first element on the periodic table?2. What is the centre of an atom called?3. True or false? Acids have a pH level below 7.4. What is the main gas found in the air we breathe?5. True or false? An electron carries a positive charge.6. Famous New Zealand scientist Ernest Rutherford was awarded a Nobel Prize in which field?7. What is the chemical symbol for gold?8. K is the chemical symbol for which element?9. What orbits the nucleus of an atom?10. At room temperature, what is the only metal that is in liquid form?11. True or false? A neutron has no net electric charge.12. A nuclear reaction where the nucleus of an atom splits into smaller parts is known as nuclear fission or nuclear fusion?13. What is H20 more commonly known as?14. What is the third most common gas found in the air we breathe?15. What is the name given to substances that are initially involved in a chemical reaction?16. True or false? Bases have a pH level below 7.17. Is sodium hydroxide (NaOH) an acid or base?18. Atoms of the same chemical element that have different atomic mass are known as?19. True or false? A proton carries a positive charge.

20. What is the fourth most abundant element in the universe in terms of mass?Chemistry Quiz Answers

 

1. Hydrogen 2. A nucleus 3. True 4. Nitrogen (around 78%)

5. False 6. Chemistry 7. Au 8. Potassium

9. Electrons 10. Mercury 11. True 12. Nuclear fission

13. Water 14. Argon (around 1%) 15. Reactants 16. False

17. Base 18. Isotopes 19. True 20. Carbon  

Identify the following items:1.__Phospholipids__ It is the lipid component of the lungs that prevents the lungs from collapsing.2.__High Density Lipoprotein or HDL__ It is also called the good cholesterol.3.__Low Density Lipoprotein or LDL___ It is also called the bad cholesterol.4.__High Density Lipoprotein__ It is considered as the lipoprotein with the highest density.5.__chylomicrons__ The lipid that stays at the point of origin in electrophoresis.6.___chylomicrons___ It causes lipemia of serum.7.___triglycerides___ The food sources of this lipid is meat fat.8.___triglycerides___ The conversion factor of this lipid, from traditional to S.I. units is 0.01129.9.___fatty acids____ It is the simplest form of lipid.10.__cholesterol__It is the basic nucleus of most steroid hormones

1. True or false? Sound travels faster through water than air?

2. Water is made up of what two elements?

3. What is another name for a tidal wave?

4. True or false? The Indian Ocean is the biggest ocean on Earth.

5. The solid state of water is known as what?

6. Can the average human survive without water for a few days or a few weeks?

7. True or false? Pure water is tasteless.

8. Nimbus, cumulus and stratus are types of what?

9. True or false? Water is an example of a chemical element.

10. Does water cover more or less than 50% of the Earth’s surface?

11. True or false? Water boils at 100 degrees Celsius (212 degrees Fahrenheit).

12. When water is cooled, does it contract or expand?

13. Water freezes at what temperature?

14. True or false? Water is easy to compress.

15. What is the chemical formula of water?

16. The deepest point in all of the world’s oceans is named what?

17. True or false? The consumption of bottled water has risen significantly over the last few decades.

18.Pure water has a pH level of a around what number?

19. What is the longest river on Earth?

20. True or false? Ice sinks in water. 

Water Quiz Answers 

1. True 2. Hydrogen and oxygen 3. Tsunami 4. False - Pacific Ocean

5. Ice 6. A few days 7. True 8. Clouds

9. False 10. More - Around 70% 11. True 12. Expand

13. 0 °C (32 °F) 14. False 15. H20 16. Mariana Trench

17. True 18. 7 19. The Nile River 20. False - It floats

1. The rice dish ‘paella’ comes from what country?2. Deer meat is known by what name?3. Are humans omnivore, herbivore or carnivore?4. What food is used as the base of guacamole?5. The range of vegetables, fruits, meats, nuts, grains, herbs and spices used in cooking are known as what?6. True or false? India is the world’s largest producer of bananas.7. What is the sweet substance made by bees?8. Lures, reels, rods, hooks, baits and nets are common equipment used in what food gathering method?9. True or false? McDonald’s has restaurants in over 100 countries around the world.10. The ‘Pizza Hut’ franchise began in what country?11. Foods rich in starch such as pasta and bread are often known by what word starting with the letter C?

12. True or false? Trans fats are good for your health.13. What is another name for maize?14. Fruit preserves made from citrus fruits, sugar and water are known as what?15. True or false? ‘Beefsteak’ is a variety of tomato.16. Dairy products are generally made from what common liquid?17. Do coconut trees grow better in cold or warm climates?18. True or false? Cooking food often transforms its chemical make up.19. What is the popular food used to carve jack-o-lanterns during Halloween?

20. Chiffon, marble and bundt are types of what?21.

Food Quiz Answers 

1. Spain 2. Venison 3. Omnivore 4. Avocado

5. Ingredients 6. True 7. Honey 8. Fishing

9. True 10. USA 11. Carbohydrates 12. False

13. Corn 14. Marmalade 15. True 16. Milk

17. Warm 18. True 19. Pumpkins 20. Cake

Decantation, distillation, precipitation, boiling of water, freezing of water, and dissolving of salt in water are physical changes. Rusting of iron (oxidation) is a chemical change.

The 'fizz' in soft drinks is caused by Carbon dioxide.

The combination of any substance with oxygen is known as oxidation.

HCl (Hydrochloric acid), H2SO4 (Sulfuric acid), and HNO3 (Nitirc acid) are famous acids.

Lemon juice is acidic in nature.

Acids turn blue litmus paper red.

NaOH (Sodium hydroxide) is a famous base.

The reaction of an acid with a base to produce only salt and water is called a neutralization reaction.

Solubility of a substance in a solvent usually increases with an increase in temperature.

If no more solute can be dissolved in a solvent at a given temperature then that solution is called a saturated solution.

Heat is liberated in exothermic reactions.

A substance that speeds up the rate of a chemical reaction without undergoing any physical or chemical change itself is known as a catalyst.

Chlorine gas is green in color.

Hydrogen gas is evolved when dilute Sulfuric acid is added to zinc.

A pH scale reading less than 7 indicates acidity.

A substance that absorbs moisture is called hygroscopic.

Charcoal, diamond, and graphite are allotropes of carbon. The lead of a pencil mainly contains graphite.

The two allotropes of phosphorus are Red and Yellow.

Elements An element is defined as a pure substance made up of one type of atoms and cannot be further subdivided into simpler substances by any physical or chemical means.

An element can be represented by using a symbol.

Examples of Elements

The symbols H2 and Fe represent the elements Hydrogen and Iron respectively.

Compounds A compound is defined as a pure substance made up of two or more types of elements (atoms) chemically combined in a fixed proportion, and it can be further subdivided into simpler substances by chemical means only.

A molecule is the smallest part of a compound, whose properties are the same as those of the compound.

A compound can be represented by using a chemical formula.

Examples of Compounds

The chemical formulae H2O and FeS represent the compounds water and Ferrous sulfide (Iron [I] sulfide) respectively.

Mixtures

A mixture is defined as an impure substance made up of two or more types of elements (atoms) or compounds or both mechanically mixed in any proportion, and it can be further subdivided into simpler substances by physical (mechanical) means.

The constituents of a mixture retain their original properties.

The constituents of a homogenous mixture are uniformly mixed thoroughout the mixture. The properties and composition of a homogenous mixture are the same throughout the mixture.

The constituents of a heterogenous mixture are not uniformly mixed thoroughout the mixture. The properties and composition of a heterogenous mixture are not the same throughout the mixture.

Examples of Mixtures

Stainless steel is a mixture (alloy) of iron, carbon, chromium, and nickel. Carbon gives hardness to the mixture. Chromium and nickel give a silvery look to the mixture.

Potassium sulfide solution is a homogenous mixture.

A mixture of water and oil is heterogenous in nature.

The reaction of an acid with a base to produce only salt and water is called a neutralization reaction.

Acids

Acids are sour in taste.

If hydronium ions are found in a solution, the solution is acidic in nature. Hydronium ions are the only positively-charged ions (cations) formed when an acid dissolves in water. All the properties of an acid are due to the presence of these ions. The chemical formula of an hydronium ion is H3O1+.

An acid is known as a 'proton donor'.

Examples of Acids

Aqua Regia contains concentrated Nitric acid and concentrated Hydrochloric acid in the ratio 1:3. Aqua Regia means 'Royal Water' in Latin. It is used to dissolve noble metals like gold and platinum.

Milk contains lactic acid. Lactic acid is named after the Latin word 'lac', which means milk.

Vinegar is very dilute acetic acid. The vinegar used in cooking contains approximately 4% of acetic acid. The chemical formula of acetic acid is CH3COOH.

Sulfuric acid is used in the manufacture of many car batteries. It is also known as 'Oil of Vitriol'. The chemical formula of Sulfuric acid is H2SO4.

Carbonic acid is responsible for the 'fizz' in soft drinks. The carbonic acid decomposes into Carbon dioxide bubbles. The chemical formula of Carbonic acid is H2CO3.

Ascorbic acid is the chemical name of Vitamin C. Deficiency of Vitamin C in the body may result in a disease known as scurvy. The chemical formula of ascorbic acid is C6H8O6.

Bases

Bases are bitter in taste and soapy to touch.

If hydroxyl ions are found in a solution, the solution is basic in nature. Hydroxyl ions are the only negatively-charged ions (anions) formed when a base dissolves in water. All the properties of a base are due to the presence of these ions. The chemical formula of an hydroxyl ion is OH1-.

A base is known as a 'proton acceptor'.

Examples of Bases

Antacids help to neutralize the acidity (of hydrochloric acid) in the stomach. They chiefly contain two bases, namely Magnesium hydroxide and Aluminum hydroxide. The chemical formula of Magnesium hydroxide and Aluminum hydroxide is Mg(OH)2 and Al(OH)3 respectively.

Sodium hydroxide is also known as 'Caustic Soda'. Its chemical formula is NaOH.

Potassium hydroxide is also known as 'Caustic Potash'. It is used in the manufacture of alkaline batteries. Its chemical formula is KOH.

Ammonia is a basic gas which is used in the manufacture of fertilizers such as Urea, Ammonium nitrate, and Ammonium sulfate. Ammonia is produced for commercial purposes by the Haber's Process. When dissolved in water, Ammonia forms a base known as Ammonium hydroxide. The chemical formula of Ammonia is NH3.

Salts

A salt is defined as a compound formed by the complete or incomplete replacement of the hydrogen ion of an acid by a basic radical.

A normal salt is formed by the complete replacement of the hydrogen ion of an acid by a basic radical whereas an acid salt is formed by the incomplete replacement of the hydrogen ion of an acid by a basic radical.

Examples of Salts

Sodium sulfate is a normal salt whereas Sodium bisulfate is an acid salt.

Sodium sulfide is soluble in water whereas Copper carbonate, Lead chloride, and Barium sulfate are insoluble in water.

Sodium carbonate is used in the manufacture of detergents and glass.

Zinc sulfide is insoluble in water whereas Potassium phosphate, Ammonium carbonate, and Barium chloride are soluble in water.

Ammonium nitrate is used in the manufacture of fertilizers.

Oxygen combines with iron to form rust. Therefore, the rust on iron is basically an oxide. The reaction of magnesium with oxygen produces magnesium oxide.

Metals that can be easily drawn into wires are known as ductile metals.

Metals that can be easily beaten into sheets are known as malleable metals.

Metals are usually good conductors of heat and electricity. They conduct heat and electricity through 'free electrons'.

An alloy is a solid solution of two or more metals.

Bronze is an alloy of copper and tin whereas brass is an alloy of copper and zinc.

Rocks that are rich in metals are known as ores.

Aluminum is extracted from the ore 'bauxite' whereas iron is extracted from the ore 'hematite'.

If a metal's ore is titled 'pyrites', then it most probably contains sulfur.

Iron is magnetic in nature.

Unlike most other metals, mercury is a liquid at room temperature.

Gold is often found in the pure state.

Metals are obtained from their oxides by the process of reduction.

To prevent corrosion, metals are often galvanized by covering them with a layer of zinc.

Sodium is very reactive and may burn on exposure to air. Therefore, it is kept under oil.

Indicators are chemical substances that are used to find out whether a given solution is acidic or alkaline by showing a color change.

pH Indicator

The pH indicator indicates the nature as well as the strength of the given medium (solution).

Examples of pH Scale Readings

A pH scale reading of less than 7 indicates an acidic medium.

A pH scale reading of more than 7 indicates a basic medium.

A pH scale reading equal to 7 indicates a neutral medium or solution (pure distilled water).

A pH scale reading of 2 indicates a strong acid.

A pH scale reading of 13 indicates a strong base.

A pH scale reading of 6 indicates a weak acid.

A pH scale reading of 8 indicates a weak base.

Litmus Indicator

Acids turn blue litmus paper red.

Bases turn red litmus paper blue.

Examples of Litmus Paper Color Changes

Sulfuric acid is obviously acidic in nature. It turns blue litmus paper red.

Sodium hydroxide is a base. It turns red litmus paper blue.

Other Indicators

Phenolphthalein solution is a colorless indicator.

Methyl orange solution is obviously an orange-colored indicator.

Bromothymol blue solution is an indicator.

Examples of Color Changes using Other Indicators

Phenolphthalein solution causes no color change in acids whereas it turns bases pink.

Methyl orange solution turns acids pink whereas it turns bases yellow.

Bromothymol blue solution turns acids yellow whereas it turns bases blue.

Name the following:1. The most radio active alkali metal2. An Organic liquid which bursts into flames on addition of conc. nitric acid.3. A metallic sulphide soluble in water4. An explosive formed when ammonia reacts with excess of chlorine5. A gas having a pungent choking smell, used to bleach fruit juices6. An unsaturated hydrocarbon formed by dehydration of ethyly alcohol with concentrated sulphuric acid7. A coloured metallic hydroxide insoluble in excess of sodium hydroxide but soluble in excess of ammonium hydroxide8. A salt which decomposes on heating to give a metal as residue9. An insoluble salt formed from two soluble salt solutions, one of which is sodium chloride solution10.A metalic sulphide insoluble in water.11. The colour of Xanthoproteic acid

12. A nitrate which leaves a black residue on heating13. The compound also known as chile salt petre14. The catalyst used for conversion of sulphur dioxide to sulphur trioxide15. A substance used to absorb arsenic impurityGive reasons for the following:1. Large quantities of sulphuric acid are used in iron and steel industry.2. All glass apparatus should be used in preparing nitric acid by heating conc. sulphuric acid and potassium nitrate.3. Lime juice has a sour taste but lime water is bitter.4. During electroplating, a small current current should be used for a longer time.5. Aluminium is extracted from its oxide by electrolytic reduction and not by conventional reducing agents.6. Ammonia is unionised in the gaseous state but in the aqueous solution is a weak electrolyte.7. Carbon tetrachloride is liquid but does not conduct electricity.8. Why is it necessary to add an acid to water before proceeding with electrolysis of water9. Aluminium is used in flash bulbs.10. Non metals are good oxidising agents.11. The catalyst chamber in the formation of ammonia provided with ammonia exchanger12. Ammonia is present in sewage water.13. Ammonia is used as a cleansing agent14. Commercial concentrated nitric acid is yellow, but turns colorless when diluted with water.15. In the laboratory preparation of nitric acid, the mixture of concentrated sulphuric acid and sodium nitrate should not be heated above 200 degrees centigrade.

Name a metal which:1. is a liquid at room temperature -2. is so soft that it can be cut with a knife.-3. is a bad conductor of heat4. is store in kerosene-5. is brittle-

Answers: 1. francium2. turpentine oil3. sodium sulphide4. nitrogen trichloride5. sulphur dioxide6. ethene7. copper hydroxide8. silver nitrate9. lead chloride10. zinc sulphide11. yellow12. Copper Nitrate13. Sodium Nitrate14. Vanadium Pentaoxide15. Ferric Hydroxide

1.  Large quantities of sulphuric acid are used in iron and steel industry to remove the coating of oxide from the surface of iron or steel before metal is plated, or before it is coated with an enamel.2. All glass apparatus should be used in preparing nitric acid by heating conc. sulphuric acid and potassium nitrate because nitric acid produced reacts with almost all the materials including cork and rubber. It does not react with glass.3.4.During electroplating, a small current current should be used for a longer time because the thickness of the coating depends on the time for which it the current is passed.5. This is because aluminium is a good reducing agent and has a great affinity for oxygen, and can’t be reduced by reducing agents.6. Ammonia is a covalent compound. Therefore it is unionised in the gaseous state but in the aqueous solution it gives NH4OH which dissociates slightly.7. Because it is a covalent compound and there are no free ions present.8. It is necessary to add an acid to water before proceeding with electrolysis of water because pure water is a poor conductor of electricity. Acid is added to make it a good conductor.9.Aluminium is used in flash bulbs because aluminium burns in oxygen to produce intense white light.10. because they gain electrons.11.The catalyst chamber in the formation of ammonia is provided with ammonia exchanger so that the outgoing ammonia gas and the unreacted gases exchange their heat with the incoming nitrogen and hydrogen.12. Ammonia is present in sewage water beacuse it is produced due to bacterial decomposition of urea present in urine.13. Ammonia is used as a cleansing agent. Ammonia is used for removing grease and perspiration stains from clothers, windows etc. because ammonia solution emulsifies fats and grease, i.e. breaks down the fat and grease molecules so that they can be removed without leaving any residue.14. Commercial concentrated nitric acid is yellow due to the presence of dissolved nitrogen dioxide in it, but turns colorless when diluted with water because nitrogen dioxide dissolves in water to form nitric acid which is colourless..15. In the laboratory preparation of nitric acid, the mixture of concentrated sulphuric acid and sodium nitrate should not be heated above 200 degrees centigrade because of the following reasons:

i) the sodium sulphate formed at higher temperatures forms a hard crust which sticks to the walls of the retort and is difficult to remove.ii) the glass apparatus may crack at higher temperature.iii) the decomposition of nitric acid occurs to a great extent at higher temperatures thereby imparting brown colour to nitric acid.

1.mercury2.sodium3.bismuth, lead4.sodium5.zinc