Silver, gold. The zinc subgroup
Answers are for parents and teachers.
1
Balance the reaction Ag + HNO₃ (conc.) → AgNO₃ + NO₂ + H₂O.
Ag + 2HNO₃ → AgNO₃ + NO₂↑ + H₂O
2
How many grams of AgNO₃ come from 324 g of Ag? (A(Ag) = 108, M(AgNO₃) = 170)
510
3
Write the equations for ZnSO₄ → Zn(OH)₂ → ZnO.
ZnSO₄ + 2NaOH → Zn(OH)₂↓ + Na₂SO₄; Zn(OH)₂ → ZnO + H₂O.
4
Why do silver objects darken with time?
Reaction with sulfur compounds in air forms black Ag₂S.
5
Name one use for each of Zn, Cd and Hg.
Zn — coating sheet iron; Cd — yellow pigment (CdS) and batteries; Hg — thermometers, amalgams.