A manufacturer compares pure metal X with an alloy made by mixing metal X with element Y. The same indentation test is carried out on each sample.
| Sample | Diameter of X atoms in pm | Diameter of Y atoms in pm | Force needed to make a 0.50 mm deep indentation in N |
|---|---|---|---|
| Pure metal X | 250 | — | 240 |
| Alloy of X and Y | 250 | 305 | 390 |
Calculate the percentage increase in the force needed to make the indentation when the alloy is used instead of pure metal X.
Explain why the alloy needs more force to make the indentation than pure metal X.
84 exam-style questions on AQA GCSE Chemistry 2.2 How bonding and structure are related to the properties of substances, covering 2.2.1a The three states of matter, 2.2.1b Limitations of the simple particle model, 2.2.2 State symbols in chemical equations, 2.2.3 Properties of ionic compounds, 2.2.4 Properties of small molecules, 2.2.5 Polymers, 2.2.6 Giant covalent structures, 2.2.7 Properties of metals and alloys, and 2.2.8 Metals as conductors. Each one has a worked solution and a mark scheme showing where the marks go.