topic 3.4

Question 1

what are the main gasses in dry air? (3.4.2)

Answer 1

nitrogen - 78%
oxygen - 21%
argon - 0.9%
carbon dioxide - 0.035% (0.04%)

Question 2

How do you test for oxygen? (3.4.2)

Answer 2

the glowing splint method;
light a splint, then wait for it to be ‘glowing’, and place it in the gas. in if relights, there is oxygen present

Question 3

what is the name given to the glowing splint method type of reaction? (3.4.2)

Answer 3

a chemical reaction

Question 4

what happens when magnesium reacts with oxygen? - combustion (3.4.2)

Answer 4

bright white light is given off, white powder is formed

Question 5

what happens when sulphur reacts with oxygen? - combustion (3.4.2)

Answer 5

blue flame

Question 6

what colour would the universal indicator turn from gas produced when sulphur and oxygen react (sulphur oxide)? why? (3.4.2)

Answer 6

the universal indicator would turn red because it is acidic

Question 7

what is an acid? (3.4.3)

Answer 7

acids are H+ (proton) donors?

Question 8

what is a base? (3.4.3)

Answer 8

bases are H+ (proton) accepters/receivers

Question 9

what is an alkali (3.4.3)

Answer 9

alkalis are OH- donors

Question 10

what are the acids with the formulae HCl, H(3)PO(4)? (3.4.3)

Answer 10

hydrochloric acid, phosphoric acid

Question 11

what are the formulae for sulphuric acid and nitric acid? (3.4.3)

Answer 11

H(2)SO(4)
HNO(3)

Question 12

are all soluble metal hydroxides acids, alkalis, or bases?

Answer 12

alkali

Question 13

are all metal oxides acids, alkalis, or bases?

Answer 13

bases

Question 14

are all metal hydroxides acids, alkalis, or bases?

Answer 14

bases