# Question ded6c

Jun 7, 2017

18.5 grams Sodium (Na)
28.5 grams Chlorine (Cl)

#### Explanation:

Find the percentage mass of each element of salt, sodium chloride (NaCl)

Sodium = 23.0 grams ( to three significant digits)
Chlorine= 35.5 grams ( to three significant digits.)

The molar mass of Sodium Chloride is
$23.0 + 35.5 = 58.5$ grams

The mass percent of sodium is

$\frac{23.0}{58.5} = 39.3$%

 39.3% xx 47 .0 g = 18.5 g

The mass percent of Chlorine is

$\frac{35.5}{58.5} = 60.7$%

 60.7% xx 47.0g = 28.5 g#

Jun 13, 2017

You need 18.5 g of sodium and 28.5 g of chlorine.

#### Explanation:

Here's another way to do the calculation.

${M}_{\textrm{r}} : \textcolor{w h i t e}{l l} 22.99 \textcolor{w h i t e}{m} 70.91 \textcolor{w h i t e}{m l l} 58.44$
$\textcolor{w h i t e}{m m m} \text{2Na" + color(white)(l)"Cl"_2 → "2NaCl}$

Calculate the mass of $\text{Na}$

$\text{Moles of NaCl" = 47.0 color(red)(cancel(color(black)("g NaCl"))) × "1 mol NaCl"/(58.44 color(red)(cancel(color(black)("g NaCl")))) = "0.8042 mol NaCl}$

$\text{Moles of Na" = 0.8042 color(red)(cancel(color(black)("mol NaCl"))) × "2 mol Na"/(2 color(red)(cancel(color(black)("mol NaCl")))) = "0.8042 mol Na}$

$\text{Mass of Na" = 0.8042 color(red)(cancel(color(black)("mol Na"))) × "22.99 g Na"/(1 color(red)(cancel(color(black)("mol Na")))) = "18.5 g Na}$

Calculate the mass of ${\text{Cl}}_{2}$

$\text{Moles of Cl"_2 = 0.8042 color(red)(cancel(color(black)("mol NaCl"))) × "1 mol Cl"_2/(2 color(red)(cancel(color(black)("mol NaCl")))) = "0.4021 mol Na}$

$\text{Mass of Cl"_2 = 0.4021 color(red)(cancel(color(black)("mol Cl"_2))) × "70.91 g Cl"_2/(1 color(red)(cancel(color(black)("mol Cl"_2)))) = "28.5 g Na}$