Unit 3 - Metals

Question 1

When metals react with water they produce…

Answer 1

Hydrogen (H₂) and a metal oxide

Question 2

When metals react with an acid they produce:

Answer 2

Hydrogen gas (H₂) and a metal salt

Question 3

When a metal react with oxygen it produce:

Answer 3

A metal oxide

Question 4

What is the test for Hydrogen gas?

Answer 4

Burn with a pop

Question 5

Write the balanced chemical equation for the following reaction:

Lithium with water

Answer 5

2Li + 2H₂O –> 2LiOH + H₂

or

Li + H₂O –> LiOH + 1/2 H2

Question 6

Write a balanced chemical equation for the reaction of magnesium with hydrochloric acid

Answer 6

Mg + 2HCl –> MgCl₂ + H₂

Question 7

Write a balanced chemical equation for the reaction of iron (III) with nitric acid

Answer 7

Fe + 3HNO₃ –> Fe(NO₃)₃ + 1.5 H₂

or

2Fe + 6HNO₃ –> 2Fe(NO₃)₃ + 3H₂

Question 8

Write a balanced chemical equation for the reaction of Potassium with oxygen

Answer 8

2K + 1/2O₂ –> K₂O

or

4K + O₂ –> 2K₂O

Question 9

Which metals can be found uncombined in the Eearth Crust? why?

Answer 9

Gold, silver and Platnium are found uncombined in the earth because they are so unreactive.

Question 10

How are reactive metals such as Lithium extracted from their ores?

Answer 10

Using electricity = ELECTROLYSIS

Question 11

What is an ore?

Answer 11

A naturally occurring solid material from which a metal or valuable mineral can be extracted profitably.

Examples of ores: Copper Oxide, Aliminium oxide…

Question 12

How are metals that don’t react with water but react with acids extracted?

Answer 12

Heat with carbons.

Question 13

Using page 10 of the databooklet, which element can be extracted by heating with carbon only?

Answer 13

Magnesium; Aluminium, Zinc, Iron, Nickel, Tin, Lead.

Question 14

Using page 10 of your databooklet, which element required electrolysis to be extracted?

Answer 14

Lithium, Potassium, Calcium, Sodium

Question 15

Does copper react with water?

Answer 15

Copper is not a very reactive metals, it is at the bottom of the reactivity serie, so it will not react with water neither with acid.

But if will react with Oxygen.

Question 16

Does Lithium react with Acid?

Answer 16

Lithium is very reactive, it will react with Water, Acid and oxygen.

Question 17

How can Mercury be extracted from its ore?

Answer 17

Heating alone is sufficient to extract Mercury from its ore.

Question 18

What type of power must be use in electrolysis?

Answer 18

DC : Direct Current.

One electrode need to be constantly positve and the other one constantly negative.

The opposite: Alternative current, alternate the charge of the electrode, and this cannot be use for electrolysis.

Question 19

Does the most reactive metals give or accept electron? Is that Oxidation or Reduction.

Answer 19

The most reactive metal want to get rid of their electron to become a more stable ion,

for example Lithium solid (Li) with the electron arrangement 2,1 want to lose an electron to become more stable and become Li⁺ with the electron arrangement: 2

Question 20

Take a mixture of Silver, Silver ions, Sodium and Sodium ions.

Ag(s); Ag⁺(aq); Na(s); Na⁺(aq)

Which one get oxidised, which one get reduced?

Answer 20

The most reactive metal will lose electron.

The least reactive metal will accept electrons from the most reactive one.

Silver ions (Ag⁺) will gain electron to become Ag(s)

Sodium (Na) will lose electron to become (Na⁺)

OIL / RIG : Oxidation Is Loss / Reduction is Gain

Sodium lose electron, it’s getting oxidised

Silver gain electron, it’s getting reduced.

Question 21

Write the redox equation between Magnesium and Iron (III) ions

Answer 21

Reaction of magnesium: Mg(s) –> Mg²⁺(aq) + 2e^- (Oxidation)

Reaction of Iron (III) ions: Fe³⁺(aq) + 3e^- –> Fe(s) (Reduction)

Balanced both half equation:

(x3) 3Mg(s) –> 3Mg²⁺(aq) + 6e^-
(x2) 2Fe³⁺(aq) + 6e^- –> 2Fe(s)

Add them together and cancel electrons:

3Mg(s) + 2Fe³⁺(aq) –> 3Mg²⁺(aq) + 2Fe(s)