Chemical reactions, formulae and equations

Question 1

In chemical reactions, how are new substances formed?

Answer 1

• The atoms in the reactants are rearranged
• No atoms/ nuclei are created or destroyed
• This means the total mass of all the reactants will equal the total mass of all the products

Question 2

What is the formulae for ammonia?

Answer 2

NH3

Question 3

What is the formulae for carbon dioxide?

Answer 3

CO2

Question 4

What is the formulae for carbon monoxide?

Answer 4

C0

Question 5

What is the formulae for Methane?

Answer 5

CH4

Question 6

What is the formulae for nitrogen dioxide?

Answer 6

NO2

Question 7

What is the formulae for nitrogen monoxide?

Answer 7

NO

Question 8

What is the formulae for sulfur dioxide?

Answer 8

SO2

Question 9

What is the formulae for sulfur trioxide?

Answer 9

SO3

Question 10

What is the formulae for water?

Answer 10

H2O

Question 11

What are the formulas for the ions Lithium, Sodium and Potassium?

Answer 11

Li+
Na+
K+

Question 12

What are the formulas for the ions Magnesium, Calcium and Barium?

Answer 12

Mg2+
Ca2+
Ba2+

Question 13

What is the formula for an aluminium ion?

Answer 13

Al3+

Question 14

What is the formula for an ammonium ion?

Answer 14

NH4+

Question 15

What is the formula for a Copper ion

Answer 15

Cu2+

Question 16

What is the formula for a silver ion?

Answer 16

Ag+

Question 17

What is the formula for a zinc ion?

Answer 17

Zn2+

Question 18

What is the formula for an ion oxide?

Answer 18

O2-

Question 19

What is the formula for an ion sulfide?

Answer 19

S2-

Question 20

What is the formula for a fluoride ion?

Answer 20

F-

Question 21

What is the formula for a chloride ion?

Answer 21

Cl-

Question 22

What is the formula for a bromide ion?

Answer 22

Br-

Question 23

What is the formula for an iodide ion?

Answer 23

I-

Question 24

What is the formula for a carbonate ion?

Answer 24

CO32-

Question 25

What is the formula for a Nitrate ion?

Answer 25

NO3-

Question 26

What is the formula for a Sulfate ion?

Answer 26

SO42-

Question 27

What is the formula for nitric acid?

Answer 27

HNO3

Question 28

What is the formula for sulfuric acid?

Answer 28

H2SO4

Question 29

What is the formula for ethanoic acid?

Answer 29

CH3COOH

Question 30

What is the formula for buckminsterfullerene?

Answer 30

C60

Question 31

Which ions always make their compound aqueous?

Answer 31

Li+
Na+
K+
NH4+
C2H2O2-
CH3COO-
HCO3-
ClO3-
ClO4-
Cl- (except if bonded to Ag/ Pb)
Br-(except if bonded to Ag/ Pb)
I-(except if bonded to Ag/ Pb)
F-(except if bonded to Ag/ Pb)
SO42-(except if bonded to Ag/ Pb/Ca/Sr/Ba)

Question 32

How do you write ionic equations?

Answer 32

• Work out the balanced symbol equation
• Add state symbols
• Split any aq species into ions
• Cancel out any ions that appear on both sides
• Write out the IONIC equation

Question 33

Can water be aqueous?

Answer 33

NO: aqueous means “dissolved in water”

Question 34

What is oxidation and reduction in terms of electrons?

Answer 34

oxidation is a LOSE of electrons

reduction is a GAIN of electrons

Question 35

Write the half equations for the electrolysis of molten aluminium oxide. What was reduced/ oxidised?

Answer 35

Al203:
Al3+ to Al:

Al3+ + 3e- —> Al
Al3+ gains electrons;
it was REDUCED

O2- to O2

202- —> O2 + 4e-
O2- loses electrons;
it was OXIDISED