Moles connect mass and particles

UNDERSTAND · PRACTISE · REVIEW

Use the molar mass stated in the question. Divide sample mass by molar mass to find amount in moles. Keep grams and grams per mole visible so the unit cancellation makes sense.

A worked example

Try this learning routine

1. Read the explanation and say the idea in your own words.
2. Cover the worked answer and attempt a similar question.
3. Check each step, including units or word meaning.
4. Record one mistake and retry a new example later.

Independent practice

Choose one answer for each question and write a reason. These are foundation activities, not a complete board examination.

1. A sample contains 18 g of water. Using molar mass 18 g/mol, how many moles?

   • 2
   • 4
   • 1
   • 3

2. A sample contains 36 g of water. Using molar mass 18 g/mol, how many moles?

   • 2
   • 5
   • 4
   • 3

3. A sample contains 54 g of water. Using molar mass 18 g/mol, how many moles?

   • 3
   • 4
   • 5
   • 6

4. A sample contains 72 g of water. Using molar mass 18 g/mol, how many moles?

   • 7
   • 6
   • 4
   • 5

5. A sample contains 90 g of water. Using molar mass 18 g/mol, how many moles?

   • 8
   • 5
   • 6
   • 7

6. A sample contains 108 g of water. Using molar mass 18 g/mol, how many moles?

   • 8
   • 6
   • 7
   • 9

Your next step

Use the same idea in a fresh example. Bring the method and your questions to a discussion with TRICEF, rather than relying on a score alone.

Original TRICEF Academy practice material. Not an official board paper. Open the answer section before printing if you want the answer key included.