Question

Calculate the percentage by mass of lead in pbco3.

Answer 1

Answer:

The correct answer is d.

Explanation:

Step 1: First we must obtain the molecular weight of $PbCO_{3}$ and Pb.

$PM_{PbCO_{3} }$ = 267,21 $\frac{g}{mol}$

$PM_{Pb}$ = 207,2 $\frac{g}{mol}$

Step 2: We can now calculate the percentage of lead in a $PbCO_{3}$ molecule by stating a simple rule of three:

$PM_{PbCO_{3} }$ -->    100%.

$PM_{Pb}$              -->    X

%Pb = $\frac{PM_{Pb}}{ PM_{PbCO_{3} }} * 100%$

%Pb = $\frac{207.2 \frac{g}{mol}}{267.21 \frac{g}{mol}} * 100%$

%Pb = 77,54 %

Have a nice day!

Answer 2

Pb/pbco3*100
207/207+12+48
207/267*100
=77.53%