Question

A chemist obtains 2.50 moles of sodium nitrate (`NaNO_3`). What is the mass of this sample?

The molar masses for the elements are Na = 23.0 g, N = 14.0 g, and O = 16.0 g.

Answer 1

Very simple. Follow below.

Explanation:

You are given `"2.50 moles"` of sodium nitrate, `(NaNO3)`.

Given moles, now, you are to convert back to mass (in grams).

To do this, you need to set up the problem as follows:

First, find the formula mass of the compound using the periodic table.

`Na = 23 g`
`N = 14 g`
`O = 16g * 3 = 48 g`

Total = 85 grams

So, for every `1 "mole"` of `NaNO_3`, you have 85 grams.

We will set up a conversion factor to solve for mass in grams of the sample using moles of `NaNO_3`.

`(2.50 cancel"moles")/1 * (85color(white)(.)"grams")/(1 cancel"mole") = "212.5 grams"`

Answer: 212.5 grams of `NaNO_3`