Question

All formula for finding mole of a substance

Answer 1

To find the number of moles of a substance, you can use the following formulas depending on the information available:

### 1. **Using Mass**
To calculate the number of moles (\( n \)) from the mass of the substance:

\[
n = \frac{m}{M}
\]

Where:
- \( n \) = number of moles
- \( m \) = mass of the substance (in grams)
- \( M \) = molar mass of the substance (in grams per mole, g/mol)

### 2. **Using Volume and Concentration**
For solutions, you can calculate moles from volume and molarity:

\[
n = C \times V
\]

Where:
- \( n \) = number of moles
- \( C \) = concentration (molarity) of the solution (in moles per liter, mol/L or M)
- \( V \) = volume of the solution (in liters)

### 3. **Using Gas Volume (Ideal Gas Law)**
For gases at standard temperature and pressure (STP), you can use:

\[
n = \frac{V}{V_m}
\]

Where:
- \( n \) = number of moles
- \( V \) = volume of the gas (in liters)
- \( V_m \) = molar volume of an ideal gas at STP (approximately 22.4 L/mol)

### 4. **Using Avogadro's Number**
When dealing with a number of particles (atoms, molecules, ions, etc.):

\[
n = \frac{N}{N_A}
\]

Where:
- \( n \) = number of moles
- \( N \) = number of particles
- \( N_A \) = Avogadro's number (approximately \( 6.022 \times 10^{23} \) particles/mol)

### Summary
Choose the appropriate formula based on the information you have:
- Use mass and molar mass for solid substances.
- Use concentration and volume for aqueous solutions.
- Use volume for gases under standard conditions.
- Use the number of particles for counting moles directly.

These formulas can help you calculate the number of moles for various substances and conditions.