Question

Calculate the number of grams of sodium in 9.1 g of each of the following sodium-containing food additives.​

NaCl (table salt)

Express your answer using two significant figures.

Answer 1

Molar mass of NaCl,

MM = 1*MM(Na) + 1*MM(Cl)

= 1*22.99 + 1*35.45

= 58.44 g/mol

mass(NaCl)= 9.1 g

use:

number of mol of NaCl,

n = mass of NaCl/molar mass of NaCl

=(9.1 g)/(58.44 g/mol)

= 0.1557 mol

This is number of moles of NaCl

one mole of NaCl contains 1 moles of Na

use:

number of moles of Na = 1 * number of moles of NaCl

= 1 * 0.1557

= 0.1557

Molar mass of Na = 22.99 g/mol

use:

mass of Na,

m = number of mol * molar mass

= 0.1557 mol * 22.99 g/mol

= 3.58 g

Answer: 3.6 g