Name:________________________
Block:_____
Date:___________________
CP Chemistry: Mole Problem Set #1
Directions: Convert the following mole problems. Be sure to use the same sig figs as the given.
**1 mole X = 6.02x1023 representative particles **
1. How many moles are carbon are there in a sample with 4.90x1022 atoms of Carbon?
Answer: 0.0814 moles C
2. How many molecules are there in a sample of 6.090 moles of CH4?
Answer: 3.666x1024 molecules CH4
3. How many formula units are there in a sample of NaCl that contains 4.90 moles?
Answer: 2.95x1024 formula units NaCl
4. How many moles of carbon dioxide, CO2, are present if there are 5.90x1030 molecules of
CO2?
Answer: 9.80x106 moles CO2
5. Zinc metal is used in alloys. One alloy contains 3.90 moles of zinc. How many atoms of
zinc is that?
Answer: 2.35x1024 atoms Zn
6. How many formula units of LiCl are present in 1.00 moles?
Answer: 6.02x1023 formula units LiCl
7. A sample containing 5.90x1028 molecules of NH3 is found in a cave. How many moles of
NH3 were found?
Answer: 9.80x104 moles NH3
8. How many molecules of chlorine gas, Cl2, are there in a sample containing 5.9045
moles?
Answer: 3.5545x1024 molecules Cl2
9. Calcium bromide, CaBr2, is found in a sample. The number of moles in the sample was
0.0041 moles. How many formula units are in the sample?
Answer: 2.5x1021 formula units CaBr2
10. How many total atoms are there in a sample of NaCl if the sample contains 4.9888 moles
of NaCl?
Answer: 6.0065x1024 atoms
** This problems is asking for total atoms. Atoms are not the representative particles for NaCl
(formula units would be – metal and a nonmetal). So, we need to look at one single formula unit
(NaCl). Each individual formula unit is composed of 1 chlorine atoms and 1 sodium atom. So,
we have an equality that there are two total atoms in 1 formula unit of NaCl. We can use this as
an equality to convert.**
4.9888 𝑚𝑜𝑙 𝑁𝑎𝐶𝑙 𝑥
6.02𝑥1023 𝑓𝑜𝑟𝑚𝑢𝑙𝑎 𝑢𝑛𝑖𝑡𝑠 𝑁𝑎𝐶𝑙
2 𝑡𝑜𝑡𝑎𝑙 𝑎𝑡𝑜𝑚𝑠
𝑥
= 6.0065𝑥1024 𝑎𝑡𝑜𝑚𝑠
1 𝑚𝑜𝑙 𝑁𝑎𝐶𝑙
1 𝑓𝑜𝑟𝑚𝑢𝑙𝑎 𝑢𝑛𝑖𝑡 𝑁𝑎𝐶𝑙