Question

How to find the mass of an acid and a base

Answer 1

To find the mass of an acid and a base, you typically need to follow a few steps involving calculations based on concentration, volume, and molar mass. Here's how to do it:

### 1. Determine the Concentration and Volume

First, you need to know:
- The concentration of the acid and base solutions (usually in moles per liter, molarity, M).
- The volume of solutions you are using (in liters or milliliters).

### 2. Calculate Moles of Acid and Base

You can calculate the number of moles (n) of the substance using the formula:

\[
n = C \times V
\]

Where:
- \( n \) = number of moles
- \( C \) = concentration (in moles per liter, M)
- \( V \) = volume (in liters, L)

**Note:** If your volume is in milliliters, you need to convert it to liters by dividing by 1000 (1 L = 1000 mL).

### 3. Convert Moles to Mass

Once you have the number of moles, you can convert it to mass (m) using the formula:

\[
m = n \times M
\]

Where:
- \( m \) = mass (in grams)
- \( n \) = number of moles (calculated from the previous step)
- \( M \) = molar mass of the acid or base (in grams per mole, g/mol)

### 4. Find Molar Masses

To perform the calculations, you will need the molar masses of the specific acid and base you're working with. You can find molar masses from periodic tables or reliable chemical databases.

### Example Calculation

**Example 1: Calculating mass of hydrochloric acid (HCl)**

- Concentration of HCl = 0.5 M
- Volume = 50 mL = 0.050 L

1. Calculate moles of HCl:
\[
n = C \times V = 0.5 \, \text{mol/L} \times 0.050 \, \text{L} = 0.025 \, \text{mol}
\]

2. Molar mass of HCl = 36.46 g/mol

3. Calculate mass:
\[
m = n \times M = 0.025 \, \text{mol} \times 36.46 \, \text{g/mol} = 0.9115 \, \text{g}
\]

**Example 2: Calculating mass of sodium hydroxide (NaOH)**

- Concentration of NaOH = 0.1 M
- Volume = 100 mL = 0.100 L

1. Calculate moles of NaOH:
\[
n = C \times V = 0.1 \, \text{mol/L} \times 0.100 \, \text{L} = 0.010 \, \text{mol}
\]

2. Molar mass of NaOH = 40.00 g/mol

3. Calculate mass:
\[
m = n \times M = 0.010 \, \text{mol} \times 40.00 \, \text{g/mol} = 0.400 \, \text{g}
\]

### Summary

With the above steps, you can determine the mass of an acid and a base given their concentration and volume. Just remember to use the correct units and convert where necessary.