Chemistry - 90934

Question 1

What is formed when a metal combines with a non-metal?

Answer 1

An ionic compound

Question 2

What is formed when non-metal elements combine with non-metal elements?

Answer 2

Covalent compounds

Question 3

What is an oxidation reaction that occurs quickly and releases heat and light (flame) known as?

Answer 3

Combustion

Question 4

Oxygen reacting with an element known as?

Answer 4

Oxidation reaction

Question 5

Thermal composition reaction

Answer 5

Heat is used to chemically break down compounds into simpler compounds. E.g copper carbonate (plus heat) -> copper oxide + carbon dioxide.

Question 6

What products are formed when the following decompose? Metal carbonate; metal hydroxide; metal hydrogencarbonate.

Answer 6

Metal carbonate -> metal oxide + CO₂. Metal hydroxide -> metal oxide + water. Metal hydrogencarbonate -> metal carbonate, CO₂ + water.

Question 7

Do metal hydroxides and carbonates of less reactive metals decompose fast or slow?

Answer 7

Fast (easily). (and metals lower on the activity series decompose faster).

Question 8

Do sodium and potassium decompose?

Answer 8

No

Question 9

Do metal hydrogencarbonates decompose?

Answer 9

Yes, readily

Question 10

Most metal carbonates, hydroxides and oxides are while, however compounds of which elements can be coloured?

Answer 10

Iron and copper.

Question 11

Limestone (calcium carbonate) is heated to produce?

Answer 11

Lime. CaCO₃ (heat) -> CaO + CO₂

Question 12

How does baking soda work? (sodium hydrogencarbonate)

Answer 12

When heated, it releases CO₂ gas, causing products to rise during baking. 2NaHCO₃ (heat) -> Na₂CO₃ + CO₂ + H2O

Question 13

Catalyst

Answer 13

Substance that alters the rate of a chemical reaction without being used up itself. Reduces the amount of energy needed for the reaction to proceed.

Question 14

Explain how a catalyst speeds up the decomposition of hydrogen peroxide at room temperature

Answer 14

Without a catalyst, decomposition of hydrogen peroxide at room temp is very slow. If a catalyst such as manganese(IV) oxide, MnO2, is present, the reaction is much quicker. 2H2O2 -> O2 + 2H2O

Question 15

Solvent

Answer 15

The liquid the solute dissolves in (usually water)

Question 16

Solute

Answer 16

The substance the dissolves in the solvent

Question 17

Solution

Answer 17

The resulting mixture when a solute dissolves in a solvent

Question 18

Soluble

Answer 18

A substance that dissolves readily in water

Question 19

Insoluble

Answer 19

A substance that does not dissolves readily in water

Question 20

Precipitate

Answer 20

A solid that formed when two solutions are mixed and one of the products is an insoluble substance

Question 21

Spectator ions

Answer 21

Ions that are present but do not take part in a reaction

Question 22

Salt

Answer 22

An ionic compound that results from the neutralisation reaction of an acid and a base.

Question 23

What happens to ionic solids during the dissolving process?

Answer 23

The ions are pulled from the ionic lattice and become separately surrounded by water molecules.

Question 24

Do all solutions of ionic solids contain cations and anions?

Answer 24

Yes

Question 25

What are ions in solution known as?

Answer 25

Aqueous ions

Question 26

Exchange reaction

Answer 26

Two solutions of ionic compounds are mixed and the ions are exchanged to form two new compounds. AB + BC -> AD + CB

Question 27

What colour are precipitates?

Answer 27

Usually white, unless iron(II), iron(III) and copper ions

Question 28

By which method can a solid precipitate be removed from a solution

Answer 28

Filtration

Question 29

How to identify a precipitate

Answer 29

Look at the ions present in the original mixture of two solutions and decide which combination of these ions forms an insoluble substance

Question 30

Solubility rules for nitrates, chlorides, sulfates, hydroxides, carbonates

Answer 30

Nitrates: all soluble. Chlorides: all soluble except AgCl, PbCl₂. Sulfates: all soluble except BaSO₄, PbSO₄, CaSO₄. Hydroxides: all insoluble except KOH, NaOH. Carbonates: all insoluble except K₂CO₃, Na₂CO₃.

Question 31

How can precipitates be predicted?

Answer 31

Using the solubility rules

Question 32

In word equations, what character/symbol identifies the precipitate

Answer 32

(s)

Question 33

Ionic equation vs net ionic equation

Answer 33

Ionic equation shows all ions present in a reaction, whilst the net ionic reaction shows only those ions which are changed.

Question 34

Single-displacement reaction

Answer 34

A single-displacement reaction, also named single-replacement reaction, is a type of oxidation-reduction chemical reaction when an element or ion moves out of one compound and into another. Element A + compound BC -> element B + compound AC.

Question 35

Symbol equation and ionic equation for: iron + copper sulfate -> iron(II) sulfate + copper.

Answer 35

Fe + CuSO₄ -> FeSO₄ + Cu.

Fe + Cu²⁺ -> Fe²⁺ + Cu.

Question 36

In a displacement reaction, which metal will displace all others from solution? (the most or least reactive)

Answer 36

The most reactive.

Question 37

What is an activity series?

Answer 37

A list of substances ordered by relative reactivity.

Question 38

An an ionic equation, which ions are not shown?

Answer 38

The spectator ions.

Question 39

What are the correct formulae for these common metal cations and non-metal anions? Ca, Mg, Al, Zn, Fe, Fe, Pb, Cu, Cl, SO4, CO3, OH, O

Answer 39

Ca²⁺, Mg²⁺, Al³⁺, Zn²⁺, Fe²⁺, Fe³+, Pb²⁺, Cu²⁺, Cl^-, SO₄^2-, CO₃^2-, OH^-, O^2-