Question

A sample of ammonium chloride (NH4Cl) has 9.8 moles. How many atoms of hydrogen are in the sample?

Answer 1

2.360 × 10^25

Explanation:

The only issue that may arise from asking a question like this is not understanding mole ratios:

Imagine 1 mol of CO2:

You need 1 mol of the end result. In the end result, you have:

1 Carbon

2 Oxygens

When you're trying to get 1 mol of the final compound, you need to have:

1 mol Carbon

2 mol Oxygen

If this doesn't make sense, Khan Academy has insightful videos showing how this works.

So, for NH4Cl, ignore everything but the H. We don't care about them.

You need 4 hydrogens to get 1 NH4Cl, so multiply whatever mole value you're given by 4. That's how many moles of hydrogen there are.

9.8 mol × 4 = 39.2mol H

So the next question is, what is a mole? The answer to this question is the same as asking what is a dozen? Well, it's just a number of things. Instead of 12, like a dozen, it's 6.02×10²³. This is called Avogadro's Number.

So say you have two dozen. You'll do 2 × 12, right?

Say you have 39.2moles. Apply the same idea, except with Avogadro's Number instead of 12:

39.2 × 6.02×10²³ = 2.360 × 10^25

So what is this number? It's how many things are in 39.2moles. We were calculating individual hydrogens, which are atoms, so this number represents how many atoms there are in 39.2moles.