JK / L = Group 7 and group 1 trends / Contact process

Question 1

What are group 7 and group 1 elements called?

Answer 1

Group 7 = Halogens

Group 1 = Alkali metals

Question 2

Reactivity trend in group 7 and group 1?

Answer 2

• More reactive as you go down group 1

- More reactive as you go up in group 7

Question 3

Steps of the contact process + all the equations

Answer 3

1 - Make sulphur dioxide gas. Roasting suphide ores or burning sulphur in air
S(l) + O2(g) —-> SO2(g)

2 - Make sulphur trioxide. React with more oxygen from the air. Add Vanadium five oxide (V2O5) as a catalyst
2SO2(g) + O2(g) 2SO3(g)

3 - Sulphur trioxide is dissolved in concerntrated sulphuric acid to make liquid Oleum
SO3(g) + H2SO4(l) —-> H2S2O7(l)

4 - Liquid oleum is diluted with measured amounts of water to create the correct concerntration of H2SO4
H2S2O7(l) + H2O(l) —-> 2H2SO4(l)

Question 4

Uses of sulphur (4)

Answer 4

• Cosmetics
• Shampoos
• Making pesticides
• Added to rubber e.g. it’s added to car tyres to toughen them up. It’s called vulcanizing

Question 5

Uses of sulphur dioxide (3)

Answer 5

• Sterilizing agent e.g. dried fruit
• Bleach for wool, silk and wood pulp to make paper
• Prevents moulds

Question 6

Disadvantage of sulphur dioxide

Why? (4)

Answer 6

ACID RAIN

• Sulphur dioxide that escapes to the air reacts with the water droplets in clouds to form dilute sulphuric acid
• Affects pH of water (kill fish) and affects species that are pH sensitive
• Ruin infrastructure
• Destroys habitats

Question 7

Describe an experiment where you make a fertilizer

Answer 7

AMMONIUM SULPHATE FERTILIZER

1 - Put a measured amount of sulphuric acid into an evaporating basin

2-Add ammonia solution a little at a time, with stirring until a distinct smell of ammonia is obtained

3-Check the pH using indicator paper. Continue with step 2 until the pH showing up as 7

4-Evaporate the solution to about 1/5 of its original volume

5-Filter off the crystals and leave to dry