C4 - Stoichiometry

Question 1

Valency (charge) of each group

Answer 1

• Group 1 - +1
• Group 2 - +2
• Group 3 - +3
• Group 4 - +/-
• Group 5 - -3
• Group 6 - -2
• Group 7 - -1
• Group 8 - 0

Question 2

Copper (II) charge

Answer 2

Cu 2+

Question 3

Iron charge

Answer 3

Fe 2+

Question 4

Chromium charge

Answer 4

Cr 3+

Question 5

Ammonium charge

Answer 5

NH(4) +

Question 6

Hydroxide charge

Answer 6

OH -

Question 7

Sulfate charge

Answer 7

SO(4) 2-

Question 8

Carbonate charge

Answer 8

CO(3) 2-

Question 9

Hydrogen carbonate charge

Answer 9

HCO(3) -

Question 10

Relative atomic mass

Answer 10

The relative atomic mass for each element can be found in the Periodic Table along with the atomic number
* The average mass of the isotopes of an element compared to 1/12th of the mass of an atom of 12C
* symbol is A(r)

Question 11

Relative molecular mass

Answer 11

The symbol for the relative molecular mass is Mr and it refers to the total mass of the molecule
* To calculate the Mr of a substance, you have to add up the relative atomic masses of all the atoms present in the formula

Question 12

Mole

Answer 12

One mole contains 6.02 x 1023 particles (e.g. atoms, ions, molecules); this number is known as the Avogadro Constant

Question 13

Volume of one mole of gas

Answer 13

24 dm(3) or 24,000 cm(3)

Question 14

Volume of gas formula (using moles)

Answer 14

Volume = Moles x Molar volume

Question 15

Moles formula

Answer 15

Mass (g) x Molar mass (g/mol)

Question 16

Limiting reactants

Answer 16

A reactant that determines the maximum amount of product that can be produced in a chemical reaction
* this is the one that will be used up first

Question 17

Concentration formula

Answer 17

Cc (g/dm(3)) = mass of solute (g) / volume of solutions (dm3)