# Question #dbdd7

May 10, 2017

The relative atomic mass of the sample of lead is 208.

#### Explanation:

You have the equation

${M}_{\textrm{r}} : \textcolor{w h i t e}{m m m l} x \textcolor{w h i t e}{m l} 35.45 \textcolor{w h i t e}{m m} x \text{+70.90}$
$\textcolor{w h i t e}{m m m m m} {\text{Pb" + "2Cl" →color(white)(ml) "PbCl}}_{2}$
$\text{Mass/g:} \textcolor{w h i t e}{m l} 1 \textcolor{w h i t e}{m l l} 0.341 \textcolor{w h i t e}{m m l l} 1.341$

$\text{Mass of Cl = 1.341 g - 1 g = 0.341 g}$

We can set up the ratio

$\left(1 \textcolor{red}{\cancel{\textcolor{b l a c k}{\text{g Pb")))}/(0.341 color(red)(cancel(color(black)("g Cl")))) = (x color(red)(cancel(color(black)("g Pb"))))/(70.90 color(red)(cancel(color(black)("g Cl}}}}\right)$

$x = \frac{70.90}{0.341} = 208$

${M}_{\textrm{r}} = 208$