Question

Write equations for the following:

a. solid nitrogen sublimes.

b. a piece of magnesium is dropped into phosphoric acid.

c. a piece of copper is dropped into hydrochloric acid.

Answer 1

A)

Recall that nitrogen is present in the atmosphere as a diatomic moleucule --> N(triple)N or simply N2

solid nitrogen = N2(s)

then, sublimation implies solid --> gas formation so

gas nitrogen = N2(g)

the equation

N2(s) --> N2(g)

b)

magnesium is mtalic solid so Mg(s)

phosphoric acid is likely to be in aqueous solution so

H3PO4(aq)

the equation

Mg(s) + H3PO4(aq) --> Mg+2(aq) + H2(g) + HPO4-(aq)

The molecular formula:

Mg(s) + H3PO4(aq) --> Mg3(PO4)2(aq) + H2(g)

the balanced equation

3Mg(s) + 2H3PO4(aq) --> Mg3(PO4)2(aq) + 3H2(g)

c)

copper is present as solid copper -- >Cu(s)

will typically form Cu2+ ions in solution, the acid will force this

so

hydrochloric acid. = HCl

Cu(s) + HCl(aq) --> H2(g) + CuCl2(aq)

balance

Cu(s) + 2H2Cl(aq) --> 2H2(g) + CuCl2(aq)