# Homework Help: Limiting reagent?

1. Apr 17, 2007

### kenon

Limiting reagent???

If there are 50g of 0.5M(molarity) HCl and 50g of 0.5M(molarity) NaOH which are allowed to react, which one is the limiting reagent? How to calculate the number of mole of limiting reagent?

2. Apr 17, 2007

### Moridin

number of moles equals the mass of the substance divided by its molar mass.

Here are some questions for you:

1. What is a limiting reagent?
2. What reaction occurs?
3. In what ratio does it occur?

3. Apr 17, 2007

### kenon

It should be neutralization, where HCl + NaOH ->NaCl + water.

From the equation, the ratio of HCl:NaOH =1:1

Since what i interested in is the enthalpy change of the reaction, so i need to know the number of mole of limiting reagent(the one which is lower in quantity, either HCl or NaOH).

Now i only got the masses of HCl(0.5M) and NaOH(0.5M) in solution, how can i obtain the number of mole of these 2 solution to compare their number of moles?

4. Apr 17, 2007

### Staff: Mentor

Do you mean 50g of 0.5M solution? If so, you need solution densities to proceed. These are tabelarized.