Question

How many moles of lithium metal would need to react with excess oxygen gas to produce 4 moles of lithium oxide in the following reaction?

2 Li + O2 → Li2O

Answer 1

@Demonx341

Answer 2

yes?

Answer 3

I need to know how to find the limiting reactant. I know that the limiting reactant is what ends the chemical reaction, & the excess is what's left after the reaction. I just don't know how to determine that by looking at an equation. Can you help?

Answer 4

@linn99123

Answer 5

this isn't a limiting reactant question. In a limiting reactant problem, you would be given \(known amounts\) of both starting materials and asked to predict a yield.

Here, you're given an amount of product that \(needs\) to be formed, and you need to find the amount of \(one\) reactant necessary to make it.

Look at the mole ratios from the balanced equation. That tells you everything

Answer 6

So I just find the molar mass?

Answer 7

no, you need to look at the coefficients in front of the formulas

Answer 8

If you're going to produce 4 moles of lithium oxide, how many \(moles\) of lithium metal are needed?

that's exactly what this question is asking

Answer 9

Right. How do I find that out though? Wouldn't there have to be more moles of lithium metal if it is going to react with excess oxygen gas?

Answer 10

they're telling you "excess" oxygen gas to make sure that all the lithium metal is used up. the amount of oxygen that's actually used isn't needed here

Answer 11

in order to make 4 moles of lithium oxide, how many moles of lithium are used?

Answer 12

the balanced reaction tells you that every time you USE 2 moles of lithium, you MAKE 1 mole of lithium oxide.

Answer 13

Oh. I just didn't understand how to read the equation to find the information. I guess it's actually really simple.Thank you.

Answer 14

so what do you think the answer is?

Answer 15

8

Answer 16

it is, GJ

Answer 17

Yep