A pottery studio uses copper oxide to make a green glaze. Fig. 1 shows copper oxide powder being warmed with dilute nitric acid in a beaker. The black solid...
Question 1 Report
A pottery studio uses copper oxide to make a green glaze. Fig. 1 shows copper oxide powder being warmed with dilute nitric acid in a beaker. The black solid disappears to form a blue solution containing a copper compound.
(a) Name the type of substance copper oxide is. [1]
(b) Complete the word equation: copper oxide + nitric acid → copper nitrate + ________. [1]
(c) Explain why no gas is expected in this reaction. [2]
This cleaning product is ammonia solution, sold for removing oil from workshop floors. Fig. 1 shows a labelled spray bottle and a pH probe in a diluted sample. The warning label says that the liquid must not be mixed with bleach.
(a) Name the type of solution ammonia makes in water. [1]
(b) Use pH values to state whether ammonia solution has a pH above or below 7. [1]
(c) Explain why goggles should be worn when spraying this cleaner. [2]
Answer Details
Metal oxides and ammonia solution
For copper oxide and nitric acid: (a) Copper oxide is a base, specifically a metal oxide. [1] (b) The missing product is water. [1] (c) This is acid-base neutralisation. No carbonate or reactive metal is present, so there is no reactant that would produce a gas. [2]
For ammonia cleaner: (a) Ammonia makes an alkali, or alkaline solution, in water. [1] (b) Its pH is above 7. [1] (c) Spray droplets could enter the eyes, and alkaline solution can irritate or damage eye tissue, so goggles are needed. [2]
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