7C2: Revision Questions:
Question
Answer
What is an element?
A substance made of only one type of atom
What is used to organise the elements?
The periodic table
What is a chemical symbol?
The one or two letter code for an element
What is an atom?
The smallest part of an element that can exist
Does one atom on its own have the properties
of an element?
No
What is a compound?
‘Two or more different types of atom joined together
‘What molecules?
‘Atoms joined together
‘What happens to the chemical properties
when atoms form compounds?
The chemical properties change
What is a chemical formula?
Tr shows the relative numbers of each atom ina
compound
How many elements are there?
92+
297C3: Revision Questions:
Question Answer
What is a chemical reaction? A change where atoms are rearranged to make new
substances.
What does reversible mean?
Tis quite easy to go back to the starting conditions
What are some signs of a chemical reaction?
Flames, sparks, smells, temperature change, bangs,
fizzing
‘Are all reactions fast? No, they go at different speeds
What can be used to speed up a reaction? A catalyst
What is special about a catalyst?
Tt speeds up a reaction without being used up.
What is a state change?
A physical change
What elements make up carbon dioxide?
Carbon, oxygen
What are the substances at the start of a Reactants
chemical reaction called?
What are the substances made by a chemical Products
reaction called?
Where do you put the reactants and products
ina word equation?
Reactants on the left
Products on the right
What is a fuel?
‘A material that burns to transfer energy by heating
What is amore scientific word For burning?
‘Combustion
What two products are made when a fuel
burns
Carbon dioxide and water
What is a fossil fuel?
Fuel made of dead organisms
What does non-renewable mean?
Cannot be replaced once they are used up
Why might hydrogen be a good fuel?
When it burns it only makes water
‘What does oxidation mean?
‘A reaction that adds oxygen to a substance
What is thermal decomposition?
Breaking up a compound by heating
‘What is made when a carbonate is heated?
‘An oxide and carbon dioxide are formed
What is the test for carbon dioxide?
Limewater turns cloudy
What is a discrete variable?
Can only have specific values
What does conservation of mass mean?
The total mass of the products is equal to the total
mass of the reactants
Why is Balancing equations important?
Tr makes them obey conservation of mass
What does exothermic mean?
Gives out energy and gets hotter
What does endothermic mean?
Takes in energy and gets colder
‘What is a hazard?
‘A possible source of danger
What is a risk
The chance of damage or injury from a hazard
457C4: Revision Questions:
Question
‘Answer
1 Give some examples of acids
Hydrochloric acid (stomach acid), citric acid (lemon
Juice), ethanoic acid (vinegar), sulphuric acid (battery
acid)
2, What type of chemical is contained in
liquid soap, oven cleaner and toothpaste?
They contain alkalis
3. What does corrosive mean?
Corrosive means a chemical could burn your skin and
eyes.
4. Give two ways of controlling risks from
corrosive solutions
Wear eye protection; keep the solution off your skin.
5, Describe a concentrated acid solution
‘A concentrated acid solution contains a high number
of acid particles in one litre of solution.
6. What is an indicator?
‘An indicator is a dye that turns a different colour in
acidic and alkaline solutions.
7. What colour does red litmus paper turn
when adding alkali?
Red litmus turns blue on adding alkali
8, What colour does blue litmus paper turn
when adding acid?
Blue litmus turns red on adding acid,
9. What pH is neutral? What colour does
Universal indicator turn in a neutral solution?
pH7 is neutral, turns Universal indicator green.
10. What sort of chemical gives pH 14? What
colour is this in Universal indicator?
‘A strong alkali would be pH 14, colour purple.
11, What sort of chemical gives pH 1? What
colour is this in Universal indicator?
A strong acid would be pH 1, colour red
12, Describe what neutral means.
Neutral means that the solution is neither acidic nor
alkaline, the pH is exactly 7.
13. Give a difference between a base and an
alkali
Alkalis are bases that dissolve in water.
14, Give the general word equation for an acid
reacting with a base
‘Acid + base > salt + water
15. Give the general word equation for a acid
reacting with a metal
Metal + acid salt + Hydrogen
16. Describe the test for Hydrogen
A lit splint makes a squeaky pop sound only when
Hydrogen is present.
17. Give the name of the liquid that is
collected when filtering a mixture.
Filtrate.
18. Explain how to make salt crystals from an
acid and a metal
React an acid with a metal or base to give a salt
Solution. Filter to remove excess metal or base.
Heat the filtrate in an evaporating basin to remove
the water. Leave the evaporating basin ina warm
place to allow the rest of the water to evaporate.
Crystals will remain.
5619. What type of salt is given when sulphuric
acid is used in the reaction?
‘Sulphate salt
20. What type of salt is given when Chloride salt
hydrochloric acid is used in the reaction?
21. What type of salt is given when nitric acid | Nitrate salt
is used in the reaction?
22, Give the name of the products when
calcium oxide is reacted with hydrochloric
acid
Calcium chloride + water
23, What is the pH scale?
The pH scale shows how acidic or alkaline a solution
is,
24, Describe how neutralisation reactions can
be helpful
Neutralising bee/ wasp stings, neutralising soil to
allow more plants to grow, neutralising lakes to enable
more wildlife to live there, neutralising stomach acid
25. Which element do all acids contain?
All.acids contain hydrogen.
26. Describe what a salt is.
‘A salt is a compound that forms when an acid reacts
with a metal element or compound. The hydrogen
atoms of the acid are replaced by atoms of the metal
element.
18. Explain how to make magnesium chloride
salt crystals from an acid and a metal.
React magnesium, magnesium oxide or magnesium
hydroxide with hydrochloric acid to give a magnesium,
chloride solution, Filter to remove excess reactant.
Heat the filtrate in an evaporating basin to remove
the water. Leave the evaporating basin in a warm
place to allow the rest of the water to evaporate.
Magnesium chloride salt crystals will remain,
57