## Atoms, Molecules, and Ions

#### Practice

1.

How many atoms does a sample of 2.60 moles sulfur (S) contain?

1.57 x 1024 atoms of S

2.

Calculate the molar mass of N2O4 and determine how many moles of it are in a 23.9 g sample.

0.260 moles

Solution

3.

How many Ethylene, C2H4 molecules are present in a 46.2 g sample? The molar mass of C2H4 is 28.0 g/mol.

9.93 × 1023 C2H4 molecules

Solution

4.

Isopropyl alcohol, also known as isopropanol, has found a widespread application in preparation of pharmaceutical products. Answer the following questions considering that the molecular formula of isopropanol is C3H8O.

a) How many moles of C3H8O are contained in a 12.0 g sample of the alcohol?
b) How many molecules of C3H8O are contained in a 12.0 g sample of the alcohol?
c) How many atoms of oxygen are contained in a 12.0 g sample of the isopropyl alcohol (C3H8O)?
d) How many atoms of carbon are contained in a 12.0 g sample of the isopropyl alcohol (C3H8O)?

a) 0.200 moles of C3H8O
b) 1.20 x 1023 molecules of C3H8O
c) 1.20 x 1023 oxygen atoms
d) 3.60 x 1023 carbon atoms

Solution

### 2 thoughts on “Molar Calculations”

1. Was great and the questions were composed great.

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