Quiz | Chemical Reactivity

1

What is the net ionic equation of: MnCl2 (aq) + (NH4)2CO3 (aq) → MnCO3 (s) + 2 NH4Cl (aq)?

Cl- (aq) + NH4+ (aq) → NH4Cl (aq)

Mn2+ (aq) + CO32- (aq) → MnCO3 (s)

MnCl2 (aq) + (NH4)2CO3 (aq) → 2 NH4Cl (aq)

Mn2+ (aq) + CO32- (aq) + 2 Cl- (aq) + 2 NH4+ (aq) → MnCO3 (s) + 2 Cl- (aq) + 2 NH4+ (aq)

A net ionic equation only shows the ions that form a solid, so here MnCO3

2

What is a Bronsted base?

A H+ acceptor

A H+ donor

An electron pair acceptor

An electron pair donor

A Brönsted base is a substance that can accept a proton (H+ acceptor)

3

Which of the following compounds is not a Lewis base?

H2O

NH3

HO-

AlCl3

A Lewis base is an electron-pair donor and so must have a lone pair of electrons

4

What is the oxidation number of the carbon atom in H2CO3?

0

+2

+4

+8

Charge of H2CO3 = 0 = Oxidation Number (O.N.) of C + 2 O.N. of H + 3 O.N. of O
O.N. of H = +1    and    O.N. of O = -2
0 = O.N. of C + 2 x 1 + 3 x (-2)    ⇒    O.N. of C = +4

5

What is the reducing agent in the reaction: Fe2O3 + 3 CO → 2 Fe + 3 CO2?

CO

CO2

Fe

Fe2O3

A reducing agent is a substance that is oxidized in a redox reaction
CO (oxidation number of C: +2) becomes CO2 (oxidation number of C: +4) ⇒ CO is oxidized since the oxidation number of the carbon atom increases

6

What kind of reactions is: 2 Ag (s) + H2S (aq) → Ag2S (s) + H2 (g)?

Combination

Decomposition

Single replacement

Double replacement

A single replacement reaction is a chemical reaction in which one element is replaced by another in a compound