12.5. Identification of ions and gases
A subsection of Chemistry, 0620, through 12. Experimental techniques and chemical analysis
Listing 10 of 359 questions
Smelling salts are sometimes used to ‘wake up’ people who feel faint. The main chemical in smelling salts is ammonium carbonate. Ammonium carbonate breaks down slowly at room temperature to release ammonia gas. ammonium carbonate → ammonia + carbon dioxide + water A few crystals of ammonium carbonate were put on a bench at the front of a classroom. ammonium carbonate A B C The students in row A could smell the ammonia 10 seconds after the smelling salts had been put on the bench. The students in row C could smell the ammonia after 40 seconds. Suggest how long it took the students in row B to smell the ammonia. Explain these results using ideas about moving particles. Ammonium carbonate has the formula (NH4)2CO3. Calculate the relative formula mass of ammonium carbonate. Ammonia is used to make fertilisers such as ammonium sulfate. State the names of the three chemical elements, essential for plant growth, that are present in fertilisers. Which one of the following statements about ammonium sulfate is correct? Tick one box. When ammonium sulfate is heated with sodium hydroxide, carbon dioxide is given off. When ammonium sulfate is added to a solution of barium chloride, a blue precipitate is formed. Ammonium sulfate can be made by adding sulfuric acid to ammonia. Farmers add ammonium sulfate to the soil to make it alkaline. Ammonium carbonate is made by heating ammonium sulfate with excess calcium carbonate. ammonium sulfate + calcium carbonate → ammonium carbonate + calcium sulfate When 132 g of ammonium sulfate is reacted with calcium carbonate, 96 g of ammonium carbonate is formed. Calculate the mass of ammonium sulfate needed to make 240 g of ammonium carbonate.
0620_s11_qp_22
THEORY
2011
Paper 2, Variant 2
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Questions Discovered
359