Types of Changes
A change in state indicates that a ____________ (physical/chemical) change has occured.
Physical
An element consists of how many types of atoms?
1
The reactants are the substances at the _________ (start/end) of a chemical reaction.
start
A substance that releases hydroxide ions is a _________.
Base
Complete the following word equation:
Acid + base -> water + ________
salt
A chemical change can be easily reversed.
True or false?
False
A mixture can be easily separated.
True or false?
True
A substance that speeds up the rate of a reaction is called a _________________.
catalyst
Which of these is not a property of bases?
A. feel slippery
B. turn litmus paper blue
C. taste sour
D. dissolve fats and oils
C. taste sour
When an acid reacts with __________, salt and hydrogen are formed.
metal
Which is not true of a chemical change?
A. difficult to reverse
B. new product is formed
C. change in state only
C. change in state only
If 2 elements are chemically bonded together, this is called a ________________.
Compound
An ____________ reaction abosrbs heat from its surroundings.
Endothermic
Acids have a pH ____________ (above/below) 7.
below
Which of the following is not a product of an acid/carbonate reaction?
A. salt
B. hydrogen
C. carbon dioxide
D. water
B. hydrogen
What is an indication that a chemical change has ocurred?
Change in colour
Change in temp.
Gas production
Precipitate formed
Give an example of a compound
Water, carbon dioxide, salt etc.
Which of these is an endothermic reaction?
A. fuel reacts with oyxgen to release heat
B. an instant ice pack is shaken
C. magnesium burns in a flame
B. an instant ice pack is shaken
Is this chemical an acid, base or salt?
HNO3
Acid
Complete the following word equation:
Fuel + __________ -> carbon dioxide + water
oxygen
A substance that changes colour in acidic or basic solutions is called an _____________.
Indicator
What is the chemical symbol for gold?
Au
Iron reacts with oxygen to form iron oxide.
In this reaction, oxygen is:
A. a reactant
B. a product
A. a reactant
A substance has a pH of 12. What is it?
A strong base
When an acid and a base react to form salt and water, this is called a ___________________ reaction.
neutralisation