# Particles In A Mole

1. A molecular mole represents a unit of measure that is a collection of 6.022 × 1023 particles. The dictionary defines this type of mole as “the amount of a substance that has a weight in grams equal to the substance’s molecular weight.” With this activity, you’ll have some fun and use your creativity to design your own mole.
2. Explain why chemists use the mole. Chemists use the mole because it is a convenient way of knowing how many representative particles are in a sample. State the mathematical relationship between Avogadro’s number and 1 mol. One mole contains 6.02 1023 representative particles. List the conversion factors used to convert between particles.
3. Mole Conversions Mole: the amount of a substance that contains 6.02 x 1023 respective particles of that substance Avogadro’s number: 6.02 x 1023 Molar Mass: the mass of one mole of an element CONVERSION FACTORS: 1 mole = 6.02 x 1023 atoms 1 mole = atomic mass (g) Try: 1. How many atoms are in 6.5 moles of zinc?

The elementary entities that can be represented in moles can be atoms, molecules, monoatomic/polyatomic ions, and other particles (such as electrons). For example, one mole of a pure carbon-12 ( 12 C) sample will have a mass of exactly 12 grams and will contain 6.02214076.10 23 (N A ) number of 12 C atoms.

Related Topics:
More Chemistry Lessons

In these lessons, we will learn
• how to calculate the mass of a substance when we are given the number of moles (mole to mass conversion).
• how to calculate the number of moles of a substance when we are given the mass (mass to mole conversion).
The following diagram shows the conversion between Mole and Mass. Scroll down the page for more examples and solutions.
Mole-Mass Equation

mass = number of moles × molar mass

where mass is in grams and the molar mass is in grams per mole.

Moles to Mass Calculation

We can use the above equation to find the mass of a substance when we are given the number of moles of the substance.

Example:

Calculate the mass of (a) 2 moles and (b) 0.25 moles of iron. (Relative atomic mass: Fe = 56)

Solution:

a) mass of 2 moles of iron
= number of moles × molar mass
= 2 × 56
= 112 g

b) mass of 0.25 mole of iron
= number of moles × molar mass
= 0.25 × 56
= 14 g

Example:

Calculate the mass of (a) 3 moles and (b) 0.2 moles of carbon dioxide gas, CO2. (Relative atomic mass: C = 12; O = 16)

Solution:

a) mass of 1 mole of CO2
= (1 × 12) + (2 × 16)
= 44 g

mass of 3 moles of CO2
= 3 × 44
= 132g

b) mass of 0.2 mole of CO2
= 0.2 × 44
= 8.8 g

Examples of moles to mass calculation
Example:
If an experiment calls for 0.200 mol acetic acid (HC2H3O2), how many grams of glacial acetic acid do we need?

## Particles In A Molecule

Formula: m = nM
• Show Step-by-step Solutions
Example:
If an experiment calls for 0.500 mol CaCO3, how many grams of pure calcium carbonate do we need? Mass to Moles Calculation

If we are given the mass of a substance and we are asked to find the number of moles of the substance, we can rewrite the above equation as

Example:

## Number Of Particles In A Molecule

Calculate the number of moles of aluminum present in (a) 108 g and (b) 13.5 g of the element. (Relative atomic mass: Al = 27)

Solution:

b)

Example:

Calculate the number of moles of magnesium oxide, MgO in (a) 80 g and (b) 10 g of the compound. (Relative atomic mass: O = 16, Mg = 24)

Solution:

a) Mass of 1 mole of MgO

= (1 x 24) + (1 x 16)

= 40 g

b)

Examples of mass to mole calculation
Example:
How many moles of acetic acid (HC2H3O 2) are present in a 5.00 g sample of pure acetic acid?
• Show Step-by-step Solutions
How to use formula mass to convert grams to moles and moles to grams?
Examples:
1. How many moles of NAOH are represented by 80.0 grams of NAOH?
2. How many grams will 3.5 moles of NAOH weigh?

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