Reactions of metals
Metals can react with water, acid and oxygen. The reactivity of the metal determines which reactions the metal participates in.
Watch this video to see a practical investigation into the reactivity of iron.
Investigating the corrosion of iron
Reactions with water
Metals can react with water, acid and oxygen. The reactivity of the metal determines which reactions the metal participates in.
When metals react with water, metal hydroxides and hydrogen gas are formed. This can be represented in different ways as shown:
Word equation
\(Calcium + water \to calcium\,hydroxide + hydrogen\)
Chemical equation
\(Ca + 2{H_2}O \to Ca(OH)_2^{} + H_2^{}\)
Ionic equation
\(Ca(s) + 2{H_2}O(l) \to Ca^{+2}(aq)+2OH^{-}(aq)\)
Reactions with acid
Metals above hydrogen on the electrochemical series react with acids
When metals react with acids, a salt of the metal and hydrogen gas are formed. The salt of the metal is named following the rules you learned in Unit 1 of the course.
Word equation
\(Magnesium + hydrochloric\,acid \to magnesium\,chloride + hydrogen\)
Chemical equation
\(Mg + 2HCl \to MgCl_2^{} + H_2^{}\)
Ionic equation
\(Mg(s) + 2H^{+}(aq)+2Cl^{-}(aq) \to Mg^{2+} (aq) +2Cl^{-}(aq)+H_{2}(g)\)
Watch this video for a practical demonstration of reacting different metals with acid.
Using a metal and an acid to produce hydrogen and a salt
Watch the video below to see the correct procedure for reacting zinc and surfuric acid. This produces hydrogen and zinc sulfate, both of which can be tested for.
Reactions with oxygen
When metals react with oxygen, metal oxides are formed.
Word equation
\(Zinc + oxygen \to zinc(II)\,oxide\)
Chemical equation
\(2Zn + {O_2} \to 2ZnO\)
Ionic equation
\(2Zn(s) + {O_2}(g) \to 2Zn_{}^{2 + }O_{}^{2 - }(s)\)
Watch this video for a practical demonstration of reacting metals with oyxgen.
Reacting metals with oxygen
Summary
The reactions of metals can be summed in the diagram below.