# Converting the molarities into moles but I'm having trouble with the reaction

• shaggyace
In summary, the conversation is about finding the pH when 45.0 mL of 0.250 M NaOH(aq) is added to 35.0 mL of 0.200 M HCl(aq). The problem involves converting molarities into moles and determining the products of the reaction, which should be salt and water. The conversation also discusses using the limiting reagent to calculate the leftover H+ and determining the pH using the total volume. Another option is to calculate pOH first if there is OH- remaining.
shaggyace
Can anyone help me with this problem?

Find the pH when 45.0 mL of 0.250 M NaOH(aq) is added to 35.0 mL of 0.200 M HCl(aq).

I started by converting the molarities into moles but I'm having trouble with what the reaction should look like. Shouldn't it produce a salt (NaCl) and water? And if so, how would I calculate the [H+] and then ph from that?

shaggyace said:
Shouldn't it produce a salt (NaCl) and water?

Yes. If you've already converted to moles and you now know that the products are salt and water, you can now determine your limiting reagent and figure out how much H+ you have left over. With that and the total volume, you can determine the pH.

Alternatively, you may have to calculate pOH first, if there is OH- left.

## 1. How do I convert molarity into moles?

To convert molarity into moles, you can use the formula: moles = molarity x volume (in liters). Make sure to convert the volume from milliliters to liters before plugging it into the formula.

## 2. What if I am given the mass of the substance instead of the volume?

If you are given the mass of the substance, you can use the formula: moles = mass / molar mass. The molar mass can be found by adding up the atomic masses of each element in the substance's formula.

## 3. What if there is more than one substance involved in the reaction?

If there are multiple substances involved in the reaction, you will need to use the molar ratio between the substances to convert the molarity into moles. This can be found by looking at the coefficients in the balanced chemical equation.

## 4. Can I convert moles back into molarity?

Yes, you can convert moles back into molarity by using the formula: molarity = moles / volume (in liters). Make sure to convert the volume from milliliters to liters before plugging it into the formula.

## 5. What if I am still having trouble with the reaction?

If you are having trouble with the reaction, make sure you have the correct balanced chemical equation and are using the correct units in your calculations. It may also be helpful to double check your conversions and ask for assistance from a peer or instructor.

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