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Chemistry: High School: 9th and 10th Grade Quiz - Chemical Reactions (Questions)

This Chemistry quiz is called 'Chemical Reactions' and it has been written by teachers to help you if you are studying the subject at high school. Playing educational quizzes is a user-friendly way to learn if you are in the 9th or 10th grade - aged 14 to 16.

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This high school Chemistry quiz is all about one of the fundamental parts of science - chemical reactions. Chemical reactions are changes to the arrangement of atoms and the molecular structure of materials. They are all around us. We can see some reactions such as fireworks and explosions. Many are very useful, like cooking and combustion. Others are more vital but are not quite as obvious such as photosynthesis and respiration. Without these reactions there would be no life on Earth - in fact there would be no universe as we know it. Everything would be made of elements and nothing would ever change. Not very exciting!

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Chemical changes are usually irreversible, you can't get easily back to the original materials (e.g. you can't un-cook an egg). However, some are easily reversed like the reaction of nitrogen and hydrogen to form ammonia and the color changes of universal indicator.

At first, chemical reactions can appear difficult to understand but basically all that happens is that the atoms of the starting materials are rearranged to form the finishing material(s). So in other words, whatever atoms are there to start with will be there at the end but the molecular structure will be in a different arrangement. The starting materials of any chemical reaction are called the reactants and the finishing materials are called the products.

Chemical reactions are described by chemical equations. Word equations are easier than balanced symbol equations but if you just remember the basics that you need to end up with exactly the same atoms as you started with, things begin to fall into place.

In high school, you need to know about a number of chemical reactions, which can be a bit worrying as there are lots to remember. Wrong! Of course, there are some specific ones to learn like the Haber process, but on the whole, you just need to learn a few basic rules - that's what's great about science, learn a few rules and it becomes a whole lot easier. One example is the reaction of strong acids with metal carbonates - these react to form a salt, water and carbon dioxide. Armed with that rule, you can easily predict the result of adding any of the strong acids to any metal carbonate - that one simple rule saves you learning dozens of individual chemical reactions.

Take this quiz on chemical reactions and see if you know some of the rules governing the molecular structures in the resulting products.

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1. What type of reaction occurs when hydrocarbons burn in an insufficient supply of oxygen?
[ ] Combustion
[ ] Incomplete combustion
[ ] Reduction
[ ] Thermal decomposition
2. What type of reaction occurs at the positive electrode when copper sulfate is electrolysed using copper electrodes?
[ ] Oxidation
[ ] Reduction
[ ] Combustion
[ ] Decomposition
3. What type of reaction does the following word equation describe?
Magnesium + zinc chloride → magnesium chloride + zinc
[ ] Oxidation
[ ] Reduction
[ ] Thermal decomposition
[ ] Displacement
4. What type of reaction occurs when limestone (calcium carbonate) is heated and becomes calcium oxide?
[ ] Oxidation
[ ] Reduction
[ ] Thermal decomposition
[ ] Combustion
5. What type of reaction is shown by the following word equation?
Hydrochloric acid + sodium hydroxide → sodium chloride + water
[ ] Decomposition
[ ] Displacement
[ ] Neutralisation
[ ] Combustion
6. What type of reaction is shown in the symbol equation?
Fe2O3 + 3CO → 2Fe + 3CO2
[ ] Oxidation
[ ] Combustion
[ ] Reduction
[ ] Decomposition
7. What reaction is occurring when decane is split into ethene and octane?
[ ] Cracking
[ ] Polymerisation
[ ] Reduction
[ ] Neutralisation
8. What reaction is involved in the hardening of vegetable oils?
[ ] Polymerisation
[ ] Cracking
[ ] Hydrogenation
[ ] Setting
9. What reaction is involved in the production of poly(ester)?
[ ] Cracking
[ ] Polymerisation
[ ] Decomposition
[ ] Neutralisation
10. What is the only reaction that removes carbon dioxide from the atmosphere naturally?
[ ] Decomposition
[ ] Combustion
[ ] Respiration
[ ] Photosynthesis
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Chemistry: High School: 9th and 10th Grade Quiz - Chemical Reactions (Answers)
1. What type of reaction occurs when hydrocarbons burn in an insufficient supply of oxygen?
[ ] Combustion
[x] Incomplete combustion
[ ] Reduction
[ ] Thermal decomposition
As there is not enough oxygen for complete combustion, the process is incomplete
2. What type of reaction occurs at the positive electrode when copper sulfate is electrolysed using copper electrodes?
[x] Oxidation
[ ] Reduction
[ ] Combustion
[ ] Decomposition
Copper atoms lose electrons to the positive electrode to become copper ions which go into solution (remember LORG - Loss of electrons is Oxidation, Reduction is a Gain of electrons)
3. What type of reaction does the following word equation describe?
Magnesium + zinc chloride → magnesium chloride + zinc
[ ] Oxidation
[ ] Reduction
[ ] Thermal decomposition
[x] Displacement
Magnesium is more reactive than zinc and so displaces it from a compound
4. What type of reaction occurs when limestone (calcium carbonate) is heated and becomes calcium oxide?
[ ] Oxidation
[ ] Reduction
[x] Thermal decomposition
[ ] Combustion
Themal = heat, decomposition = break down
5. What type of reaction is shown by the following word equation?
Hydrochloric acid + sodium hydroxide → sodium chloride + water
[ ] Decomposition
[ ] Displacement
[x] Neutralisation
[ ] Combustion
Acid + alkali is a neutralization reaction
6. What type of reaction is shown in the symbol equation?
Fe2O3 + 3CO → 2Fe + 3CO2
[ ] Oxidation
[ ] Combustion
[x] Reduction
[ ] Decomposition
OK, technically, there is an oxidation too, but you should have recognized this as being one of the reactions in the blast furnace which has the iron as its focus so at this level, this equation shows the reduction of iron oxide to iron by the removal of oxygen
7. What reaction is occurring when decane is split into ethene and octane?
[x] Cracking
[ ] Polymerisation
[ ] Reduction
[ ] Neutralisation
Long chain hydrocarbons are split into shorter chain hydrocarbons by cracking
8. What reaction is involved in the hardening of vegetable oils?
[ ] Polymerisation
[ ] Cracking
[x] Hydrogenation
[ ] Setting
Hydrogenation involves adding hydrogen to vegetable oils to harden them
9. What reaction is involved in the production of poly(ester)?
[ ] Cracking
[x] Polymerisation
[ ] Decomposition
[ ] Neutralisation
Polymers are formed from many monomers. Monomers is a general term describing any small and reactive molecules that can be joined together to form a polymer
10. What is the only reaction that removes carbon dioxide from the atmosphere naturally?
[ ] Decomposition
[ ] Combustion
[ ] Respiration
[x] Photosynthesis
All the other reactions here put carbon dioxide into the atmosphere