At 75 ∘C75\,^\circ\text{C}75∘C, the pure substances X2\text{X}_2X2 and Y2\text{Y}_2Y2 react to form the pure compound XY\text{XY}XY. No water is present.
| Substance | Change-of-state temperature |
|---|---|
| X2\text{X}_2X2 | boiling point = 60 ∘C60\,^\circ\text{C}60∘C |
| Y2\text{Y}_2Y2 | melting point = 25 ∘C25\,^\circ\text{C}25∘C; boiling point = 110 ∘C110\,^\circ\text{C}110∘C |
| XY\text{XY}XY | melting point = 95 ∘C95\,^\circ\text{C}95∘C |
A student writes this equation:
X2(l)+Y2(aq)→2XY(g)\text{X}_2(\text{l}) + \text{Y}_2(\text{aq}) \rightarrow 2\text{XY}(\text{g})X2(l)+Y2(aq)→2XY(g)
Write the equation with the correct state symbols at 75 ∘C75\,^\circ\text{C}75∘C.
Use the data to explain each state symbol you give.
The reaction is repeated at exactly 95 ∘C95\,^\circ\text{C}95∘C.
Suggest the state symbol or state symbols that could be used for XY\text{XY}XY as it forms. Explain your answer.
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.