Standard Grade Revision Unit 14 Q. 1 Industrially ammonia (NH 3 ) is made by reacting together nitrogen and hydrogen. (a) What is the source of the (i) nitrogen used in the process? (ii) hydrogen used in the process/ (b) What is the name given to the industrial process used to manufacture ammonia. (c) What is the name of the catalyst used in the process? (d) The yield of ammonia drops as the temperature of the reaction increases. Explain why the reaction is carried out at temperatures of about 500 o C. Standard Grade Chemistry (a) (i) Nitrogen comes from the air. (ii) Hydrogen comes from water or methane. (b) Haber Process. (c) Iron. (d) Reaction is too slow at lower temperatures.

Unit 14 Revision Q2. Fritz was investigation the properties of ammonia. (a)Why did the water rise up the test tube when the stopper was removed. (b)When the stopper was removed the reading on the pH meter changed. Suggest what the new reading would been. Standard Grade Chemistry (a) Ammonia is very soluble in water. (b) pH value greater than 7 (ammonia is an alkaline gas).

Standard Grade Chemistry Q3. Ammonium nitrate is made by the reaction of ammonia with nitric acid. Ammonia is made by passing a mixture of nitrogen and hydrogen through a catalyst chamber. Unreacted nitrogen and hydrogen are removed and returned to the catalyst chamber. The ammonia gas then enters a reaction vessel in which ammonium nitrate is produced. Copy this flow chart and use the information above to complete it. hydrogen ammonia Unreacted nitrogen and ammonia Ammonium nitrate

Unit 14 Revision. Standard Grade Chemistry Q4. (a) How are plants such as peas and clover able to convert nitrogen from the air into nitrogen compounds? (b) Nitrogen and oxygen in the air can be converted into oxides of nitrogen What provides the energy for this process? (c) Plants need phosphorus to grow. Suggest why calcium phosphate is not suitable as a fertiliser. You may wish to use page 5 of the data booklet. (c) Phosphorus is one of the essential elements supplied by fertilisers. Name the two other essential elements. (a) These plants have nitrifying bacteria in root nodules. The bacteria can convert nitrogen in the air into nitrogen compounds in the soil. (b) The energy from a lightning discharge. (c) Calcium phosphate is insoluble. Plants need fertilisers in soluble form. (d) Potassium and nitrogen.

Unit 14 Revision. Standard Grade Chemistry Q5. (a) The flow diagram shows how ammonia is converted to nitric acid. ammonia X reactor nitrogen dioxideabsorber air airnitric acid (HNO 3 ) (i) Name the industrial process used to manufacture nitric acid. (ii) Name the catalyst used in the reactor. ( iii) Name substance X. (b) Ammonia and nitric acid react to form ammonium nitrate. (i) Explain why ammonia is able to react with nitric acid. (ii) Give a use for ammonium nitrate. (c) Calculate the percentage of nitrogen in ammonium nitrate (NH 4 NO 3 ). (a)(i) Ostwald Process.(ii) Platinum(iii) water (b)(i) Ammonia is an alkaline gas. (ii) Nitrogen containing fertiliser. (c) 35%

Standard Grade Chemistry Q 6. The names of several compounds are shown in the box. potassium nitratesodium hydroxidelithium sulphate aluminium chloride ammonium chloride calcium phosphate (a) Identify the two compounds which can be used as fertilisers. (b) Identify the two compounds which react together to produce ammonia. (a)Potassium nitrate and ammonium chloride. (b)Sodium hydroxide and ammonium chloride. Q. Nitrogen forms many useful compounds. Compound Formula Y(NH 4 ) 3 PO 4 potassium nitrateKNO 3 ureaCO(NH 2 ) 2 (a) (i) Name compound Y. (ii) Compound Y can be used as a fertiliser. Why are fertilisers added to the soil? (b) Which acid is used to make potassium nitrate? (a) Ammonium phosphate. (b) To increase crop yields. (c) Nitric acid.

Unit 14 Revision. Standard Grade Chemistry Q7. ( a) The flow chart shows some processes which take place in an industrial chemical complex. water methane air ammonia plantphosphoric acid plant fertiliser plant (a) Air and water are used as raw materials because they contain the elements needed to make ammonia. Suggest one other reason why they are used as raw materials. (b) Which reactant for the ammonia plant must be produced in the reaction between methane and water? (c) Name the salt formed in the fertiliser plant. (a)They are cheap. (b)Hydrogen. (c) Ammonium phosphate.

Unit 14 Revision. Q8. The reaction for the production of ammonia in the Haber Process is shown below. N 2 + 3H 2  2 NH 3 (a) A Haber process plant converts 1400 tonnes of nitrogen into ammonia. Calculate the mass of ammonia produced. (b) How is the ammonia produced removed from the nitrogen and hydrogen? (c) Increasing the pressure gives a bigger yield of ammonia. Most Haber Process plants operate about about 150 to 200 atmospheres pressure. Suggest a reason why the do not operate at much higher pressures. (a)1700 tonnes. (b)The ammonia is liquefied to remove it from the gaseous nitrogen and hydrogen. (c)Much higher pressures are not used as this would raise the cost of the plant used to make ammonia to too high a level.