Hydrogen and water

Question 1

what do metals above hydrogen form when react with dilute HCl or sulphuric acid?

Answer 1

metal salt and hydrogen

Question 2

observation of magnesium with HCl or sulphuric acid

Answer 2

• bubbles of gas
• disappears
• reaction gets hot
• colourless solution formed

Question 3

observation of aluminium with HCl or sulphuric acid

Answer 3

• slow to react when cold
• bubbles form when heated
• disappears
• colourless solution formed

Question 4

observation of zinc with HCl or sulphuric acid

Answer 4

• bubbles of gas
• disappears
• colourless solution formed

Question 5

observation of iron with HCl or sulphuric acid

Answer 5

• bubbles of gas
• disappears
• pale green solution formed

Question 6

combustion of hydrogen

Answer 6

hydrogen burns when heated in air or oxygen

Question 7

what is the product of combustion of hydrogen?

Answer 7

water (initially water vapour but when cooled it will condense to form water)

Question 8

test for hydrogen

Answer 8

hold a lighted splint to mouth of tube should make a squeaky pop

Question 9

how to test for water

Answer 9

add liquid to anhydrous copper sulfate - should turn powder from white to blue

Question 10

how to test for PURE water

Answer 10

boil liquid to measure BP or measure freezing point - should be 100c or 0c
- if liquid contains impurities it will have a BP more than 100 and freezing point less than 0c