Questions I Got Wrong P3

Question 1

Observations with magnesium reacting with steam

Answer 1

Bright white light & white solid formed.

Question 2

Observations of calcium reacting with oxygen

Answer 2

Yellow flame & white solid forms

Question 3

Why is the entropy of lattice dissociation of barium oxide less endothermic than the enthalpy of lattice dissociation of magnesium oxide

Answer 3

Bariumion is larger than magnesium ion, meaning it has a weaker attraction to the oxide ion

Question 4

Why do ka expressions not include water

Answer 4

The concentration of water is effectively constant

Question 5

What are the observations of magnesium & steam

Answer 5

White light & white solid formed

Question 6

Observation in the reaction phosphorus (V) oxide & water

Answer 6

Violent reaction& colourless solution formed

Question 7

Why is Cu+ not coloured?

Answer 7

Cu+ has a full d subshell so no d-d transitions are possible

Question 8

What about vanadium ions makes them good for use as a catalyst

Answer 8

Have variable oxidation states

Question 9

Give a reason why a support medium is used in catalysts

Answer 9

To increase surface area

Question 10

Phosphorus burning in air

Answer 10

P4 + 5O2 -> P4O10

Question 11

PH of H2SO3 and H2SO4

Answer 11

2-5
0-1

Question 12

Al2O3 acting as an acid:

Answer 12

Al2O3 + 2NaOH + 3H2O -> 2NaAl(OH)4

Question 13

Al2O3 acting as a base:

Answer 13

Al2O3 + 3H2SO4 -> Al2(SO4)3 + 3H2O

Question 14

Why is carbon monoxide toxic

Answer 14

Takes the place of O2 in haemoglobin

Question 15

When using coloured compounds, how can you use a colorimeter to determine the conc. of a solution

Answer 15

1) Find absorbance of known concentrations
2) Read conc. of unknown from calibration graph

Question 16

What is a buffer solution

Answer 16

A solution that has a pH that remains approximately constant when a small amount of acid or base/alkali is added to it