The Mole

Question 1

What is the mole?

Answer 1

The mole is a number but it is a very large number.

Question 2

What is the gram formula mass (GFM)?

Answer 2

The GFN of a substance is known as the mass of one mole.

Question 3

How can you calculate the mass, no. Moles?

Answer 3

By using the m Triangle
n GFM

Question 4

How do you calculate no. Moles, concentration or volume?

Answer 4

Using the two formula triangles: m=n/GFM and n=c/v

Question 5

What is a standard solution?

Answer 5

A solution of accurately known concentration.

Question 6

What are the two rules when making a standard solution?

Answer 6

The correct mass of the solute must be measured accurately (preferably using a 3dp balance)
The correct glassware must be used to ensure accurate measurement of volume.

Question 7

What equipment do you need for making a standard solution?

Answer 7

Volumetric flask, Beaker, Wash bottle, 3 d.p balance, stirring rod, spatula, pipette dropper, distilled water, weighing boat, funnel

Question 8

What is the first step of making a standard solution?

Answer 8

Calculating the mass of a solute

Question 9

How do you calculate the mass of solute?

Answer 9

Work out the number of moles needed to make up the solution by using n=cxv, then work out the GFM of the substance, then work out the mass of substance needed by using m=nxGFM

Question 10

what do you need to make a standard solution?

Answer 10

volumetric flask
Wash bottle
Beaker
Three decimal place balance
Stirring rod
Spatula
Deionised water
Dropper pipette

Question 10

How to prepare a standard solution

Answer 10

1. Work out mass of solute needed (no. Moles, gfm then mass)
2. Take a clean dry beaker and place it on the balance. Take the balance and carefully weigh out the required mass of solute.
3. Add deionised water from wash bottle to dissolve it and stir with a glass rod until all of the solid is dissolved.
4. Transfer the solution into a volumetric flask. Use deionised water from the wash bottle to rinse out the beaker and rinse the glass rod. Do this at least twice.
5. Add water from the wash bottle to just below the line on the flask. Add the last few drops with a dropper Pipette to make sure that the bottom of the meniscus is on the line
6. Put the lid on the flask and invert it several times to ensure thorough mixing.