Can someone show me how to get this answer?

Question

How many molecules of CaCl2 are present in 6.45 g sample of CaCl2?

Answer 1

1) First, you should know the molecular mass of CaCl2:

M (CaCl2) = 111 g/mol

2) We can compute number of moles of CaCl2:

n(CaCl2) = mass(CaCl2) / M(CaCl2) =
n(CaCl2) = 6.45 g / 111 g/mol = 0.058 moles

3) Using the Avogadro number (6.02 x 10^23 molecules/mol) we can know the number of molecules in 6.45 g of CaCl2:

# of molecules CaCl2 = 6.02 x10^23 x 0.058 moles =
= 3.5 x 10^22 molecules


That´s it!

Good luck!

Answer 2

It's simple. You just have to do a few stoichiometric conversions:

6.45 g CaCl2 * (1 mol CaCl2/110.98 g) * (6.02 x 10^23 molecules / 1 mol)

= 3.50 x 10^22 molecules

Answer 3

I will show you HOW to get it...not get it FOR YOU.

1. Convert grams CaCl2 to moles CaCl2 (via molecular wt.)
2. Convert moles CaCl2 to molecules CaCl2 by Avogadro's #.

YOu need to practice the rest on your own, my friend. Or you'll flunk you exam.

Answer 4

First find the number of mols by dividing the mass by the molecular weight of calcium chloride. Then use avagadros number to convert mols to the number of molecules.

Answer 5

What is the molecular weight of Calcium chloride?
110.98 grams/mole

Divide the mass of your sample by the molecular weight, that will give you the number of moles of calcium chloride you have.

Multiply the number of moles by Avogadro's Number (6.023x10^23) to get the number of molecules.

In mathematical terms:

# molecules = (6.45 g/110.98 g/mole) * 6.023x10^23

Answer 6

Conceptually this is the same question you asked 2 hours ago and received 2 fairly detailed answers for. Apparently you are only interested in filling in the answers and not learning how to solve the problem.