Moles + Balance Equations

Question 1

What is Avogrados constant (number)

Answer 1

6.022 x 10^23

Question 2

what is the idea behind avogadros constant

Answer 2

6.022 x 10^23 is the number of particles in one mole of any element

Question 3

what is the equation to work out moles of a substance

Answer 3

moles = mass / Mr

Question 4

what is the equation to work out mass of a substance

Answer 4

mass = Mr* moles

Question 5

what are the units for moles

Answer 5

mol

Question 6

How do you calculate mass of x atoms of a certain molecule

Answer 6

use the x atoms and divide by avogrados constant to get the moles

moles * Mr = mass of substance

Question 7

What is the general structure to answer a question where you need to work out the mass of a substance in a balance equation
Where you already know the mass of another in the equation

Answer 7

1. use other part of equation to work out moles (mass/Mr)
2. look at equation and work out moles of substance you want mass of (i.e look at ratios etc.)
3. mass = Mr * moles to calculate desired substance

Question 8

How can we calculate the ratio of substance to how much water is trapped within it

Answer 8

1. Calculate the moles of dry crystals (mass/Mr)
2. Calculate moles of water through working out change in mass of wet and dry crystals then (mass/Mr)
3. Put into a ratio of dry: water
   and make it 1:n