How to find moles from grams?
Understand the Problem
The question is asking how to convert grams to moles, which involves using the molar mass of a substance. This process typically requires identifying the substance and its molar mass to perform the conversion.
Answer
The number of moles = \frac{\text{mass (grams)}}{\text{molar mass (g/mol)}}
Answer for screen readers
The final answer is the number of moles obtained from the conversion.
Steps to Solve
- Determine the substance
Identify the chemical substance you are converting from grams to moles. The substance's molecular formula or name should be given.
- Find the molar mass
Calculate the molar mass of the substance. This can be done by adding the atomic masses of all the elements in the molecule. For example, for water (H₂O), the molar mass can be calculated as:
- Hydrogen: 2 atoms × 1 g/mol = 2 g/mol\
- Oxygen: 1 atom × 16 g/mol = 16 g/mol\
- Molar mass of H₂O: 2 g/mol + 16 g/mol = 18 g/mol
- Apply the conversion formula
Use the formula to convert grams to moles:
$$ ext{moles} = \frac{ ext{mass (grams)}}{ ext{molar mass (g/mol)}} $$
For example, to convert 36 grams of water (H₂O) to moles:
$$ ext{moles} = \frac{36 ext{ g}}{18 ext{ g/mol}} = 2 ext{ moles} $$
The final answer is the number of moles obtained from the conversion.
More Information
This formula is used in chemistry to relate the mass of a substance to the number of moles, which is useful for stoichiometric calculations.
Tips
A common mistake is to incorrectly calculate the molar mass of the substance. Double-check each element's atomic mass and ensure correct multiplication and addition.