Two liquids were mixed together in a test tube. Which one of these would NOT show that a chemical reaction had taken place?
A The tube got warm.
B Bubbles of gas were given off.
C A brightly coloured solid formed in the tube.
D One of the liquids floated on top of the other.
Which of these changes is a chemical reaction?
A Melting some margarine in a pan
B Boiling a kettle of water
C Frying an egg
D Cooling a drink by putting an ice cube in it.
Which statement is true?
A All reactions need energy to start them off.
B Some reactions need energy to start them off.
C All reactions happen when two chemicals are mixed.
D All reactions happen very quickly.
A chemical reaction:
A always produces a gas.
B is always reversible.
C makes new substances.
D does not make new substances.
The substances that you get at the end of The substances that you get at the end of a chemical reaction are called:
A reactants.
B chemicals.
C products.
D gases.
Hydrogen gas:
A burns with a squeaky pop.
B makes a glowing splint relight and burn brightly.
C puts a glowing splint out.
D turns universal indicator solution red.
When a fuel burns there is:
A a reversible physical change.
B a reversible chemical change.
C an irreversible physical change.
D an irreversible chemical change.
Which of these candles will burn the longest?
A mixture is:
A just one substance, like pure salt.
B two or more things mixed together, like nuts and raisins.
C two things joined together, like flour and sugar in a baked cake.
D a lot of the same thing put together.
Salt seems to disappear if you stir it into water. Which statement is true?
A The salt dissolves because it is insoluble.
B The salt dissolves because it is soluble.
C The salt melts because it is soluble.
D The salt melts because it is insoluble.
When you add salt to water:
A the salt is the solvent.
B the water is the solute.
C the salt is the solute.
D the water is the solution.
Filtering cannot be used to separate:
A sand from a mixture of sand and water.
B sugar from sugar solution.
C tea leaves from a pot of tea.
D leaves from a mixture of leaves and pond water
Most water has chemicals dissolved in it because:
A it is pure.
B rain water has lots of chemicals dissolved in it.
C the water dissolves chemicals from rocks it passes through.
D the water dissolves chemicals from the pipes it flows through.
A solid dissolved in water can be obtained by:
A evaporating the liquid.
B using a sieve.
C using a filter.
D freezing the liquid.
Which sentence is not true?
A Rock salt is a mixture of rock and salt.
B Rock salt can be used to make pure salt to put on food.
C You can get salt from rock salt using a sieve.
D You can get salt from rock salt by dissolving, filtering and evaporating.
Pure water can be made from inky water by:
A filtering it.
B evaporating it.
C distilling it.
D adding more water to it.
The two steps in distillation are:
.
A filtering followed by evaporation.
B evaporation followed by condensation.
C condensation followed by filtering
D filtering followed by condensation
Distillation can not be used to separate:
A sand from sugar.
B petrol from crude oil.
C pure water from sea water.
D alcohol during the production of whisky.
Chromatography is:
A a way of separating different liquids from each other.
B a way of separating different dissolved colours from each other.
C a way to separate a liquid from a solid which doesn’t dissolve.
D a special way to draw a graph.
Chromatography will only work if:
A a lot of each chemical is used.
B the special paper has been warmed before it is used.
C the special paper is moved during the experiment.
D the chemicals to be separated dissolve in the liquid used.
The diagram shows a chromatogram. Which two chemicals are the same?
A A and B
B C and B
C D and F
D A and G
A saturated solution:
A is always cold.
B has a lot of water in it.
C will not dissolve any more solvent.
D will not dissolve any more solute.
You can tell if a solution is saturated because:
A it will be transparent.
B there will be bits of undissolved solid in it.
C it will be coloured.
D it will be hot.
Only 20 g of a salt will dissolve in 100 g of water at room temperature. If you use hot water instead:
A less than 20 g will dissolve.
B only 20 g will dissolve.
C more than 20 g will dissolve.
D no salt will dissolve.
The solubility of a substance is: .
A the mass of solute that will dissolve in 100 ml of water
B the mass of solvent that will dissolve in 100 ml of water.
C the volume of water that 100 g of solute will dissolve in.
D the volume of water that 100 g of solvent will dissolve in.
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