1When lemon juice is stirred into milk, what change do you see between the milk before and after? Does it taste the same?
2In the reaction between a piece of zinc and dilute hydrochloric acid, which substances are the reactants?
3What substances are formed when zinc reacts with hydrochloric acid, and how is the reaction written down?
4What is a chemical reaction? Give one example of each of its three kinds.
5State the difference between a word equation and a formula equation.
6Why is \( \mathrm{Mg + O_2 \rightarrow MgO} \) an unbalanced equation? Write its balanced form.
7Count the atoms of each element in \( \mathrm{2KClO_3 \rightarrow 2KCl + 3O_2} \) to show that it is balanced.
8In \( \mathrm{2H_2(g) + O_2(g) \rightarrow 2H_2O(l)} \), what do (g) and (l) mean?