Download Week 12 - Day 1 | Day 2 | Day 3 | Lab | Skills Test

The Mole Concept:
A mole is:



6.02 x 1023 of anything.
The molar mass in grams of a substance contains one mole of particles.
Avogadro’s Number = 6.02 x 1023
The mole is important because:


The mole concept allows us to weigh atoms in the lab.
The mole concept allows us to compare amounts of atoms in chemical
reactions.
Basic mole calculations: convert mass to moles, and moles to molecules or atoms.
The following factor-label equalities are used in mole calculations
These equalities are used in mole calculations:
1 mole = 6.02 x 1023atoms or molecules = formula mass in grams
The examples below are set up correctly.
1. Given 25.2 grams of carbon, how many atoms do you have?
25.2
2. Given 2.5 grams of water, how many molecules do you have?
2.5
3. Given 3.5 moles of sodium chloride, how many grams do you have?
4. What is the mass of 9.99 x 1015 molecules of silver nitrate?
9.99 x 1015
Factor-label tips:
Setting up the factor-label problem is just as important as the answer
Form the habit of working neatly, canceling units, and circling the answer
Remember, units are just as important as numbers in the answer
Notebook Assignment #1:
Work the following mole calculation practice problems.
Show the factor-label calculation used to work each problem.
1. A raindrop contains about 0.05 grams of water.
a. How many molecules of water are in a raindrop?
2. What is the mass in grams of 0.452 mole of C6H12O6?
3. Calculate the mass in kilograms of 0.681 mole of ammonia gas, NH3.
4. Determine the number of potassium atoms in 3.05 moles of K.
5. How many molecules are in 39.0 grams of Fe2S3?
6. Calculate the mass in grams of 2.23 moles of nitrogen molecules (HINT –
careful – this is diatomic, remember?).
7. How many atoms are in 6.4 grams of copper?
Check your answers below **some answers are rounded – so don’t worry if you
are off slightly in the hundredths place.
Research Links:

More About Moles - Diamond Bar High School ChemTeam
Practice problem answers:
1.
2.
3.
4.
5.
6.
7.
you are on your own for this one – check with Mrs. Summerlin
81.44 grams C6H12O6
0.01 kg NH3
1.84 x 10 24 K+
1.13 x 10 23 molecules Fe2S3
62.48 g N2
6.06 x 10 22 copper atoms