C5

Question 1

What is an ore ?

Answer 1

Rocks containing enough metal that it is economical to extract the metal.

Question 2

State the reactivity series from most reactive to least reactive.

Answer 2

Potassium
Sodium
Lithium
Calcium
Magnesium
Aluminium
(carbon)
Zinc
Iron
Tin
Lead
(hydrogen)
Copper
Silver
Gold
Platinum

Question 3

How do you test for hydrogen gas ?

Answer 3

squeaky pop when lit

Question 4

Write the ionic equation and half equations: Mg + CuSO4 -> MgSO4 + Cu

Answer 4

ionic eq:
Mg + Cu(2+) –> Mg(2+) + Cu

half eqs:
Cu(2+) + 2e- –> Cu
Mg –> Mg(2+) + 2e-

Question 5

General eq for a metal + acid.

Answer 5

metal + acid –> salt + hydrogen

Question 6

What is a salt ?

Answer 6

A compound made when the hydrogen ions in an acid are partially or wholly replaced by metal or ammonia ions.

Question 7

In a reaction between a metal and acid to form a salt, which of the two is oxidised and which is reduced ?

Answer 7

• metal reduced
• acid oxidised

Question 8

General eq for acid + base.

Answer 8

acid + base –> salt + water

Question 9

General eq. for acid + metal carbonate.

Answer 9

acid + metal carbonate –> salt + water + carbon dioxide gas

Question 10

Describe how to obtain a pH curve.

Answer 10

• 20 cm^3 sodium hydroxide solution in beaker
• pH probe in beaker
• measure + record initial pH
• set up burette (rinse with distilled water then some hydrochloric acid) with hydrochloric acid in it
• add 5 cm^3 hydrochloric acid at a time whilst swirling beaker to mix
• measure + record pH between each addition
• observe when the pH suddenly jumps from alkaline to acidic; this is the pH curve
• plot on a graph

Question 11

What is the relationship between H+ ion concentration and pH ?

Answer 11

If H+ ion conc. increases by 1 order of magnitude, pH unit decreases by 1.