5.2: Unit 5 Practice Problems
- Page ID
- 260646
Question 1.
Given that the following reactions occur, rank the elements Li, K, Ca, and Ba in an activity series from highest activity to lowest.
2K + BaCl2 → 2KCl + Ba
Li + KCl → LiCl + K
Ba + CaCl2 → 2BaCl + Ca
- Answer
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Li, K, Ba, Ca
Question 2.
Write the balanced chemical equations for the following reactions and then rank the metals in an activity series from highest to lowest.
- magnesium metal reacts with zinc (II) nitrate to form magnesium nitrate and zinc metal.
- zinc metal reacts with iron (III) nitrate to form zinc (II) nitrate and iron metal.
- iron metal reacts with cobalt (II) nitrate to form iron (III) nitrate and cobalt metal.
- Answer
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Mg + Zn(NO3)2 → Mg(NO3)2 + Zn
3Zn + 2Fe(NO3)3 → 3Zn(NO3)2 + 2Fe
2Fe + 3Co(NO3)2 → 2Fe(NO3)3 + 3Co
Mg, Zn, Fe, Co
Question 3.
Write the balanced chemical equations for the following reactions and indicate which metals are more active than hydrogen.
- magnesium reacts with HCl to form magnesium chloride and H2 gas.
- gallium reacts with HCl to form gallium chloride and H2 gas.
- Sr reacts with nitric acid (HNO3) to form strontium nitrate and H2 gas.
- Hg does not react with nitric acid.
- Answer
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Mg + 2HCl → MgCl2 + H2
2Ga + 6HCl → 2GaCl3 + 3H2
Sr + 2HNO3→ Sr(NO3)2 + H2
Hg + HNO3→ No reaction
Mg, Ga, and Sr are more active than hydrogen and Hg is less active.