(U1) Formulae, Equations And Amounts Of Substance

Question 1

Give the formula of a sulfate ion

Answer 1

SO₄^2-

Question 2

Give the formula of a sulfite ion

Answer 2

SO₃^2-

Question 3

Give the formula of a thiosulfate ion

Answer 3

S₂O₃^2-

Question 4

Give the formula of a hydrogensulfate ion

Answer 4

HSO₄^-

Question 5

Give the formula of a hydrogencarbonate ion

Answer 5

HCO₃^-

Question 6

Give the formula of a carbonate ion

Answer 6

CO₃^2-

Question 7

Give the formula of a nitrate ion

Answer 7

NO₃^-

Question 8

Give the formula of a nitrite ion

Answer 8

NO₂^-

Question 9

Give the formula of a phosphate ion

Answer 9

PO₄^3-

Question 10

Give the formula of a chlorate ion

Answer 10

ClO₃^-

Question 11

Give the formula of a hypochlorite ion

Answer 11

ClO^-

Question 12

Give the formula of a hydroxide ion

Answer 12

OH^-

Question 13

Give the formula of a dichromate ion

Answer 13

Cr₂O₇^2-

Question 14

Give the formula of a chromate ion

Answer 14

CrO₄^2-

Question 15

Give the formula of a permanganate ion

Answer 15

MnO₄^-

Question 16

Give the formula of an ammonium ion

Answer 16

NH₄⁺

Question 17

What is avogadro’s constant?

What is its value?

Answer 17

• The number of particles (atoms or molecules) in 1 mole of a substance
• 6.02 x 10²³

Question 18

Give the equation linking number of particles and moles

Answer 18

Moles = particles / avogadro’s constant

N = parti. / L

Parti.
N | L

Question 19

Give the equation linking moles and mass

Answer 19

Moles = mass / relative formula mass

N = M / Mr

M
N | Mr

Question 20

What is water of crystalisation?

Answer 20

Water which is chemically bonded within a crystal structure

Question 21

What is an anhydrous salt?

What is a hydrated salt?

Answer 21

• Salt containing no water of crystallisation
• salt containing water of crystalisation

Question 22

State the equation for Avogadro’s Law on gases at room temp and pressure

Answer 22

Volume = number of moles x 24

V = N x 24

dm³ = mol x 24

V
N | 24

Question 23

State the equation linking concentration, moles and volume

Answer 23

Conc (C) = number of mol (N) / volume (V)

N = C (mol/dm³) x V (dm³)

N
C V