Brass is made from copper and zinc. Brass is harder than both copper and zinc.
A student says:
"Brass must be a compound of copper and zinc, because its properties are different from the properties of both metals."
Which response to the student is correct?
The student is correct, because a new substance with different properties has been made.
The student is wrong. Brass is a mixture, and the zinc atoms, which are a different size, distort the layers of copper atoms so they slide less easily.
The student is wrong. Brass is a mixture, so its properties must be an average of the properties of copper and zinc.
The student is correct, because copper and zinc atoms share electrons to form strong covalent bonds.
61 exam-style questions on OCR GCSE Chemistry 6.1 Improving processes and products, covering 6.1.1 Extracting metals industrially and by electrolysis, 6.1.2 Life cycle assessment and recycling, 6.1.3 Biological methods of metal extraction, 6.1.4 The Haber process and the production of fertilisers, 6.1.5 Alloys and their uses, 6.1.6 Corrosion and its prevention, 6.1.7 Comparing and selecting materials, and 6.1.8 Industrial conditions, rate and position of equilibrium. Each one has a worked solution and a mark scheme showing where the marks go.