Chem Ammonia AfL

1 Name:______________________________( ) Class:_________ Date:___________ Ammonia AFL Multiple-Choice Questions (10 marks) 1. When 1 mol of nitrogen is reacted with 3 mol of hydrogen at 250 atm and 450ºC in the presence of an iron catalyst, less than 2 mol of ammonia is formed. Which of the following best explains this observation? A The pressure used was too low. B The temperature used was too low. C The nitrogen and hydrogen used in the reaction contained impurities. D The reaction of nitrogen and hydrogen to form ammonia is reversible. ( ) 2. In the Haber process, gases are combined directly in a hydrogen to nitrogen ratio of ____________. A 1 : 1 B 2 : 1 C 1 : 3 D 3 : 1 ( ) 3. The catalyst used in the Haber process is ____________. A copper B iron C hydrogen chloride D nickel ( ) 4. Ammonia gas is produced when ammonium chloride is heated with ____________. A calcium carbonate B nitric acid C potassium hydroxide D water ( ) 25

2 Use the following information to answer Questions 5 and 6. The Haber process is used to manufacture ammonia gas. The reaction is exothermic and the chemical equation for the process is: N2(g) + 3H2(g) ⇌ 2NH3(g) 5. What is the effect of increasing the pressure inside the reaction vessel on the rate of production and the yield of ammonia gas? ( ) 6. What is the effect of increasing the temperature inside the reaction vessel on the rate of production and the yield of ammonia gas? ( ) 7. Which of the following statements is not true of the Haber process? A The raw material, nitrogen gas, is obtained from the cracking of petroleum. B Liquid ammonia is the product of the Haber process. C Nitrogen and hydrogen gases are compressed at 250 atm during the process. D Unreacted nitrogen and hydrogen are recycled and transferred back into the converter. ( ) 8. Which of the following statements are true of the Haber process? 1 An increase in pressure increases the speed of reaction. 2 An iron catalyst is used to increase the yield of ammonia. 3 A high temperature of 450ºC is used to increase the yield of ammonia. 4 A relatively low pressure of 250 atm is used because it is costly to maintain a high pressure. A 1 and 4 B 1, 3 and 4 C 2 and 3 D 1, 2, 3 and 4 ( ) Rate Yield A decrease decrease B increase unchanged C increase decrease D increase increase Rate Yield A decrease decrease B increase unchanged C increase decrease D increase increase

3 9. Which ion will react with ammonium sulfate to give ammonia gas? A NH 4+ B OH– C H + D Cl– ( ) 10. Which of the following will not react with ammonium salts to give ammonia gas? A Limewater B Po