Question

How many moles of H2O can be formed when 3.5 moles of NH3 react with 2.2 moles of O2?
Be sure to balance the equation. (1 point)

NH3 + O2 yields NO + H2O

1.8 moles
2.3 moles
2.6 moles
5.2 moles

Answer 1

\( \text{NH}_3 + \text{O}_2 \to \text{NO} + \text{H}_2\text{O}\)

Can you balance the equation first?

If you already know and you're looking to save time, may I introduce you to
https://www.webqc.org/balance.php

But if you don't know how to do it, you should learn now. It's something you really need to know. Tell me and we can go over it!

Now on to what the question is actually trying to make you learn by practicing:

Answer 2

So first step- which is the most important step
BALANCE YOUR EQUATION

Next, fortunately they gave us the reactants in moles.
If they give you a value in GRAMS, you MUST convert it to moles. You do that by calculating the molar mass of the compound and using that ratio to convert from grams to moles.

Answer 3

So figure out what your limiting reactant is

Remember that our chemical reaction gives us the molar ratios

so FOR EXAMPLE, if we had

1 A + 4 B --> 2 C + 4 D

That means for 1 moles of A and 4 moles of B, we will form 2 moles of C and 4 moles of D

if we only have 1 mole of A and 2 moles of B, then
for 1 moles of A, we need 4 moles of B. But we only have 2 moles of B.
for 2 moles of B, we need 1/2 mole of A and we have 1 mole so that means we can use up all 2 moles of B and 1/2 a mole of A and we'll be left with 1/2 a mole of A.

So B is our limiting reagent because that's going to run out first

And if they ask how much of the products we're forming:
since B is our limiting reagent, just take a look at the ratios again
1 mole of A with 4 moles of B gives us 2 moles of C and 4 moles of D

so with 2 moles of B, we can only form 1 mole of C and 2 moles of D
and that would be how many moles of product we get

Answer 4

so similarly for your question,

FIRST
find the balanced reaction

SECOND
figure out what the limiting reactant it

And then finally, you can figure out how many moles of the product you'll make because the chemical reaction is in a mole to moles ratio