Amount Of A Substance

Question 1

What is Avogadro constant

Answer 1

One mole of any substance (element or compound) contains the same number of particles- 6.02x10^23

Question 2

What is a mole (mol)

Answer 2

A measure of the number of particles (atoms, ions or molecules) contained in any substance

Question 3

How do you calculate the amount of a substance (no. of moles)

Answer 3

Mass of a substance (g)
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Atomic (or formula) mass (g/mol)

Question 4

How do you work out the mass of something needed

Answer 4

Amount (mol) x formula mass

Question 5

What is a limiting reactant

Answer 5

• sometimes when two chemicals react together, one chemical is completely used up during the reaction. when one chemical is used up, it stops the reaction going any further, this is called the LIMITING REACTANT
• the other chemical which is not used up is said to be in excess