Consider equation 3A+B=C+D. You react 4 moles of A with 2 moles of B. Which of the following is true?

1) Limiting reactant (L.R.) is one with higher molar mass
2) A is L.R. because you need 6 moles of A and have only 4 moles
3) B is L.R. because you have fewer moles of B than A
4) B is L.R. because 3A molecules react with each B molecule
5) Neither reactant is limiting

if you have 2 moles of B

you need 6 moles of A

In other words you do not have enough A

I guess I just said 2) :)

To determine the limiting reactant in a chemical reaction, we need to compare the stoichiometric ratio of the reactants with the actual amount used. In this case, we have 4 moles of A and 2 moles of B.

To calculate the amounts of C and D, we can use the equation 3A + B = C + D. Since we have 4 moles of A, and the stoichiometric ratio is 3:1 (3 moles of A for every 1 mole of B), we would need 12 moles of A to react with all the B. Since we only have 4 moles of A, it is not enough to fully react with the 2 moles of B.

Therefore, option 2) A is L.R. because you need 6 moles of A and have only 4 moles is correct. A is the limiting reactant because it is the one that is consumed completely and limits the amount of product that can be formed.

To determine the limiting reactant in a chemical reaction, you need to compare the stoichiometry of the reactants (the coefficients in front of each compound or molecule in the balanced chemical equation) with the actual amounts of the reactants given.

In this case, you are given that you react 4 moles of A with 2 moles of B, based on the equation 3A + B = C + D.

To find the limiting reactant, let's compare the stoichiometric ratios for A and B in the balanced equation:

From the equation, it is clear that 3 moles of A react with 1 mole of B. Therefore, the stoichiometric ratio of A to B is 3:1.

Now, consider the actual amounts of A and B you have:

You have 4 moles of A and 2 moles of B.

To determine the moles of B that would be required to react with 4 moles of A, you can use the stoichiometric ratio:

4 moles of A * (1 mole of B / 3 moles of A) = 4/3 moles of B.

Since you have 2 moles of B, which is less than the required 4/3 moles, B is the limiting reactant in this case.

Therefore, the correct answer is:

3) B is the limiting reactant because you have fewer moles of B than A.

'-1 = 1