Chapter 3 Practice Paper: Chemical Changes — question paper

Section A: Multiple-choice questions[10 marks]

Answer all questions. For each question, write the letter (A, B, C or D) of the correct answer in the brackets provided.

1. 1

   Rust forming on a wet iron nail is

   1. Aa chemical change.
   2. Bonly melting.
   3. Cdissolving without a new substance.
   4. Da change of state only.
   ( )
2. 2

   In the word equation magnesium + oxygen → magnesium oxide, the product is

   1. Aoxygen.
   2. Bmagnesium.
   3. Cmagnesium oxide.
   4. Dwater.
   ( )
3. 3

   A lighted splint at the mouth of a test tube gives a squeaky pop. The gas is

   1. Acarbon dioxide.
   2. Bhydrogen.
   3. Coxygen.
   4. Dnitrogen.
   ( )
4. 4

   Sodium hydroxide solution is added to hydrochloric acid until the indicator is green. The two products are

   1. Aa metal and oxygen.
   2. Bhydrogen only.
   3. Ccarbon dioxide only.
   4. Da salt and water.
   ( )
5. 5

   A student dips blue litmus into vinegar. The paper

   1. Aturns red.
   2. Bstays blue.
   3. Cturns green.
   4. Drelights.
   ( )
6. 6

   A gas turns limewater milky. The gas is

   1. Ahydrogen.
   2. Boxygen.
   3. Ccarbon dioxide.
   4. Dwater vapour.
   ( )
7. 7

   Heating calcium carbonate until it breaks down into simpler substances is

   1. Adissolving.
   2. Ba physical change only.
   3. Cneutralisation.
   4. Dthermal decomposition.
   ( )
8. 8

   Iron wool rusts inside a sealed jam jar. The mass of the sealed jar stays the same because

   1. Aatoms are destroyed.
   2. Bthe atoms are rearranged and none escape.
   3. Cmagnesium oxide has no mass.
   4. Dthe flask melts.
   ( )
9. 9

   Iron turning into rust in damp air is an example of

   1. Aoxidation.
   2. Bfiltration.
   3. Ca physical change.
   4. Dneutralisation.
   ( )
10. 10

    A gardener tests rainwater with Universal Indicator and the paper turns green. The rainwater is

    1. Astrongly acidic.
    2. Bstrongly alkaline.
    3. Cneutral.
    4. Da solid element.
    ( )

Section B: Structured questions[20 marks]

Answer all questions in the spaces provided. Show your working for calculations.

1. 1

   A student adds magnesium to hydrochloric acid. A gas is given off.

   1. (a)

      The gas pops with a lighted splint. Name the gas.

      [1]
   2. (b)

      Write the word equation for the reaction.

      [2]
   3. (c)

      State the test and the positive result for oxygen.

      [1]
   4. (d)

      State the test and the positive result for carbon dioxide.

      [1]
2. 2

   Hydrochloric acid is added to sodium hydroxide until the solution is neutral.

   1. (a)

      Write the word equation.

      [2]
   2. (b)

      State the colour of Universal Indicator in the acid before the alkali is added.

      [1]
   3. (c)

      State the colour of Universal Indicator when the solution is neutral.

      [1]
   4. (d)

      Name this type of reaction.

      [1]
3. 3

   Magnesium burns in oxygen inside a sealed flask. In a second experiment the same reaction is done in an open beaker.

   1. (a)

      Explain why the mass of the sealed flask does not change.

      [2]
   2. (b)

      Explain why the mass of the open beaker and its contents can increase.

      [2]
   3. (c)

      State why it is wrong to say the missing atoms were destroyed if a gas escapes from an open beaker in a different reaction.

      [1]
4. 4

   Iron gates and fuels both take part in chemical changes.

   1. (a)

      State two substances, other than iron, that rusting needs.

      [2]
   2. (b)

      State how a coat of paint slows rusting.

      [1]
   3. (c)

      Write a word equation for the burning of a fuel that produces carbon dioxide and water.

      [2]