Topic #4: Chemical Changes Flashcards Preview

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Flashcards in Topic #4: Chemical Changes Deck (18):
1

What happens when metals react with oxygen?

A metal oxide is produced
This is a oxidation reaction because it gains oxygen

2

State the series of reactivity.

Potassium
Sodium
Lithium
Calcium
-------------- react with cold water
Magnesium
Aluminium
-CARBON-
Zinc
Iron
------------------ react with steam
Tin
Lead
--------------reaction boundary for dilute acid
-HYDROGEN-
Copper
Silver
-------------- reaction boundary for oxygen
Gold
Platinum
------------------ No reaction

3

What will displace a metal from its compound?

A more reactive metal

4

How are metals found?

Unreactive metals (eg. gold) are found in the earth
Most metals require extraction from ores via chemicla processes

5

How are metals extracted from ores?

The oxide is reduced (loses oxygen) by bioleaching

ONLY IF IT IS ECONOMICALLY VIABLE

6

What is phytomining?

Planting a plant over an ore and letting the roots absorb ions, then burn it to get the ions off

7

What is OIL RIG in terms of electrons?

Oxidation
Is
Loss

Reduction
Is
Gain

8

List the acid reactions

Acid + metal = salt and hydrogen
Acid + metal (hydr)oxide = salt and water
Acid + metal carbonate = salt and water and carbon dioxide
Acid oxide + base = salt and water

9

What happens in neutralisation?

Acids react with alkalis/bases to form salts and water, or carbonates to add carbon dioxide

10

How are soluble salts made by acids?

By adding solid insoluble substances

11

What do all acids have in aqueous solutions?

H+ ions

12

What do all alkalis have in aqueous solutions?

OH- ions

13

How ionised are different strength acids?

Strong acids (eg nitric, sulphuric, hydrochloric) are fully ionised
Weak acids (eg citric, ethanoic) are only partially ionised

14

What factor does the H ion concentration decrease by per pH?

Ten

15

What happens at the electrodes during electrolysis?

Ions are discharged

16

What are cations, cathodes, anions and anodes?

Anode- positive, attracts cations (negative charge)
Cathode- negative, attracts anions (positive charge)

17

When are ions replaced and where?

Cathode: If they are less reactive than hydrogen (oxidation)
Anode: If they are less reactive than hydroxide (reduction)

18

What is the name of the electrolyte substance?

Cryolite