A technician prepares two reactants and then mixes them at room temperature.
| Substance | Observation |
|---|---|
| Copper sulfate | Blue crystals are stirred with water until they can no longer be seen. The mixture can be poured. |
| Sodium hydroxide | White pellets are stirred with water until they can no longer be seen. The mixture can be poured. |
| Copper hydroxide | A new blue material forms when the two mixtures are added together, and it settles at the bottom. |
| Sodium sulfate | It cannot be seen, but it is present in the clear liquid above the blue material. |
The equation for the reaction is:
CuSO4(…)+2NaOH(…)→Cu(OH)2(…)+Na2SO4(…) \mathrm{CuSO_{4}(\ldots) + 2NaOH(\ldots) \rightarrow Cu(OH)_{2}(\ldots) + Na_{2}SO_{4}(\ldots)} CuSO4(…)+2NaOH(…)→Cu(OH)2(…)+Na2SO4(…)Use the observations to give the state symbol for each substance in the equation.
A student says that copper sulfate should have the state symbol (l)\mathrm{(l)}(l) in the equation, because the copper sulfate mixture can be poured.
Explain why the student is wrong.
134 exam-style questions on OCR GCSE Chemistry 3.1 Introducing chemical reactions, covering 3.1.1 Writing formulae and balanced chemical equations, 3.1.2 Formulae of compounds from ions, and state symbols, 3.1.3 Conservation of mass and observed changes in mass, 3.1.4 Half equations and balanced ionic equations, 3.1.5 The mole and the Avogadro constant, and 3.1.6 Stoichiometry, limiting reactants and reacting masses. Each one has a worked solution and a mark scheme showing where the marks go.