Question

Calculate the molecular (formula) mass of each compound: (a) dinitrogen pentaoxide; (b) lead(ll) nitrate; (c) calcium peroxide.

Answer 1

Answer:

a) The molecular  mass of each compound dinitrogen pentaoxide is 108 g/mol.

b) The molecular  mass of each compound  lead(ll) nitrat is 331 g/mol.

c) The molecular  mass of each compound calcium peroxide is 72 g/mol.

Explanation:

a) Molecular mass of dinitrogen pentaoxide that $N_2O_5$ be M.

Mass of nitrogen atom =  14 g/mol

Mass of oxygen atom = 16 g/mol

$M=2\times 14 g/mol+5\times 16 g/mol=108 g/mol$

b) Molecular mass of  lead(ll) nitrate that $Pb(NO_3)_2$ be M.

Mass of lead = 207 g/mol

Mass of nitrogen atom =  14 g/mol

Mass of oxygen atom = 16 g/mol

$M=1\times 207 g/mol+1\times 2\times 14 g/mol+3\times 2\times 16 g/mol=331 g/mol$

c)Molecular mass of calcium peroxide that $CaO_2$ be M.

Mass of calcium atom =  40 g/mol

Mass of oxygen atom = 16 g/mol

$M=1\times 40 g/mol+2\times 16 g/mol=72 g/mol$