How to convert grams to moles?
Understand the Problem
The question is asking how to convert a measurement in grams to a quantity in moles, which involves using the molar mass of the substance. This will usually require knowing the substance in question to find its molar mass, and then applying the formula: moles = grams / molar mass.
Answer
\text{moles} = \frac{\text{grams}}{\text{molar mass}}
Answer for screen readers
To convert grams to moles, you divide the mass in grams by the molar mass of the substance.
Steps to Solve
- Determine the Molar Mass of the Substance
Find the molar mass of the substance in grams per mole (g/mol) from the periodic table or other reference source. For example, consider you have water (H$_2$O); the molar mass of H$_2$O is calculated as:
$$2 (1.01 ext{ g/mol}) + 16.00 ext{ g/mol} = 18.02 ext{ g/mol}$$
- Measure the Mass in Grams
Measure the mass of the substance you have in grams.
- Use the Conversion Formula
Convert grams to moles using the formula:
$$\text{moles} = \frac{\text{grams}}{\text{molar mass}}$$
For example, if you have 36.04 grams of water (H$_2$O):
$$\text{moles} = \frac{36.04 \text{ grams}}{18.02 \text{ g/mol}} = 2 \text{ moles}$$
To convert grams to moles, you divide the mass in grams by the molar mass of the substance.
More Information
This conversion is fundamental in chemistry for relating mass to the number of particles in a substance.
Tips
A common mistake is to confuse molar mass units. Ensure you use grams per mole (g/mol).