Chemistry End of Year 8 Flashcards
What are the numbers in the pH scale?
0-14
What pH are the weakest acids?
6
What pH are the strongest acids?
0
What pH are neutral substances?
7
What pH is the weakest alkali?
8
What pH is the strongest alkali?
14
What is an indicator?
Something that changes colour to show whether something is an acid, an alkali or a neutral
What are the two popular indicators?
Litmus paper and universal indicator
What is the difference between litmus paper and universal indicator?
Litmus paper only indicates if something is acid or alkali but universal indicator shows how strong it is
Acid+alkali->
salt+water(neutral)
Hydrochloric acid+sodium hydroxide->
Sodium chloride+water
HCl+NaOH->
NaCl+H₂0
In chemical reactions, nothing gets…
Created or destroyed
In chemical reactions atoms BLANK themselves.
Re-arrange
What get broken in the re-arranging of atoms in chemical reactions?
Chemical bonds
No BLANK is lost in a chemical reaction.
Mass
What are 3 examples of visible changes that may occur in a chemical reaction?
Gas coming off, solid being formed, a change in colour
What are the 3 things needed for combustion?
Fuel heating and oxygen
What are hydrocarbons?
Fuel containing only hydrogen and carbon
Hydrocarbon + oxygen->
Carbon dioxide+water
Combustion is an example of a BLANK reaction.
Oxidation
What is an example of an oxidation reaction other than combustion?
Rusitng
What is thermal decomposition?
A reaction where a substance breaks down into two or more other substances while being heated.
Is thermal decomposition a chemical reaction or chemical change?
Chemical change
Copper carbonate->
Copper oxide + carbon dioxide
CuC03->
CuO+CO2
