Dry air is passed over hot copper until all the oxygen has reacted.
The volume of gas at the end of the reaction is 120 cm^3
What is the starting volume of dry air?
A steel bicycle which had been left outdoors for several months was starting to rust.
What would not reduce the rate of corrosion?
Responda
A Remove the rust and paint the bicycle.
B Remove the rust and store the bicycle in a dry shed.
C Remove the rust and wipe the bicycle with a clean, damp cloth.
D Remove the rust and wipe the bicycle with an oily cloth.
Questão 3
Questão
Which statements about water are correct?
1 Household water contains dissolved salts.
2 Water for household use is filtered to remove soluble impurities.
3 Water is treated with chlorine to kill bacteria.
4 Water is used in industry for cooling.
Responda
A 1, 2, 3 and 4
B 1, 2 and 3 only
C 1, 3 and 4 only
D 2, 3 and 4 only
Questão 4
Questão
Farmers use fertilisers to replace minerals in the soil that have been removed by the crops they grow.
Which elements in the soil are replaced by adding fertilisers?
Responda
A Ca, P, O
B K, O, S
C N, K, P
D N, O, S
Questão 5
Questão
Which statement is correct?
Responda
A Atmospheric carbon dioxide is not a cause of climate change.
B Atmospheric methane is produced by respiration.
C Burning natural gas decreases the level of carbon dioxide in the atmosphere.
D Decomposition of vegetation causes an increase in atmospheric methane.
Questão 6
Questão
Which statement about sulfur and its compounds is not correct?
Responda
A Sulfur dioxide is used as a food preservative.
B Sulfur dioxide turns acidified aqueous potassium manganate(VII) from purple to colourless.
C Sulfur forms a basic oxide.
D Sulfur is used in the manufacture of sulfuric acid.
Questão 7
Questão
Ammonium nitrate is a common fertiliser used by farmers to increase the yield of their crops.
Which compound reacts with ammonium nitrate to form ammonia?
Responda
A calcium hydroxide
B potassium nitrate
C sodium chloride
D sodium phosphate
Questão 8
Questão
Which process does not release a greenhouse gas?
Responda
A digestion of food in cows
B reaction between zinc and hydrochloric acid
C respiration by animals
D thermal decomposition of calcium carbonate
Questão 9
Questão
Which row describes the uses of sulfur and sulfur dioxide?