Question

calculate the mass percentage of oxygen in Pb (NO3)2
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Answer 1

Answer:

Based on the molecular formula of Pb(NO3)2, there are 6 moles of O in 1 mole of Pb(NO3)2. The molar mass of Pb(NO3)2 is 207.20 g/mol Pb + 2(14.01 g/mol N) + 6(16.00 g/mol O) = 331.22 g/mol.

Answer 2

The mass percentage of oxygen in $Pb (NO_{3})_{2}$ is 29%

• First molecular mass of $Pb(NO_{3})_{2}$ need to be calculated.
• This can be done by adding the atomic mass of each atom of the compound.
• So, each atom will be separated;
• Atomic mass of lead (Pb) = 207
• Atomic mass of nitrogen (N) = 14
• Atomic mass of oxygen $(O_{2})$ = 16
• Now, adding all the atoms;

$Pb + (N)_{2} + (O)_{6}$

207 + 2 × 14 + 6 × 16 = 331

• So, $Pb(NO_{3} )_{2}$ has a molecular mass = 331 g/mol.
• The mass percentage of oxygen can be calculated by using the following formula
• = $(\frac{molecular mass of oxygen}{molecular mass of Pb(NO_{3})_{2} })$   × 100
• $(\frac{96}{331})$ × 100= 29%

Hence, the percentage of mass of oxygen in $Pb(NO_{3})2$

is 29%.