Chapter 4: Acids And Redox (4.1-4.3)

Question 1

What happens when you add a base and an acid?

Answer 1

The base neutralises the acid to form a salt and water.

Question 2

What happens in neutralisation in terms of ions?

Answer 2

The H+ ions from the acid are replaced by metal or ammonium ions from the base.

Question 3

What is the ionic equation of reacting an acid with an alkali? I’m

Answer 3

H+(aq) + OH-(aq) -> H2O (l)

Question 4

What does a metal carbonate neutralise an acid to form?

Answer 4

Salt, water and carbon dioxide

Question 5

How do you make a standard solution?

Answer 5

1) Weigh solid
2) Dissolve solid in distilled water below the mark
3) Transfer solution to volumetric flash (RINSE THE BEAKER WITH DISTILLED WATER)
4) Fill flask to graduation line with distilled water (AVOID PARALLAX ERROR)
5) INVERT VOLUMETRIC FLASK SEVERAL TIMES - mixes solution

Question 6

How many decimal places does a burette reading have?

Answer 6

It is measured to the nearest 0.05, so it has to be either a 0 or 5 and has to be measured to 2 decimal places.

Question 7

Describe the procedure of an acid base titration

Answer 7

1) Add 25cm[3] (pipette) of alkali to conical flask
2) Add acid to burette and measure reading
3) Add indicator to the conical flask
4) Run the acid into the alkali until the indicator changes colour
5) Record the final burette reading
6) Quick trial titration to get approximate titre
7) Repeated accurately, adding solution dropwise we end point approaches until two accurate titres are concordant.

Question 8

When is the oxidation number 0?

Answer 8

In a pure element

Question 9

How do you work out total charge of a combined atom?

Answer 9

Sum of the oxidation numbers

Question 10

How do you know the oxidation number of the ion of an element ?

Answer 10

It is the same as the ionic charge but the sign comes before the number

Question 11

What is the oxidation number of H in metal hydrides?

Answer 11

-1

Question 12

What is the oxidation number of O in peroxides?

Answer 12

-1

Question 13

What is the oxidation number of O when bonded to F?

Answer 13

+2

Question 14

What do the Roman numerals in compounds mean?

Answer 14

The oxidation number of the element you don’t know the oxidation number of.

Question 15

Describe oxidation and reduction in terms of oxygen

Answer 15

Oxidation is the addition of oxygen and reduction is removal of oxygen

Question 16

Describe oxidation and reduction in terms of electrons

Answer 16

Oxidation is losing, reduction is gaining (OIL RIG)

Question 17

Describe oxidation and reduction in terms of oxidation numbers

Answer 17

Reduction is a decreases in oxidation number but oxidation is an increase in oxidation number

Question 18

define an acid

Answer 18

a species that releases H+ ions in solution

Question 19

define strong acid

Answer 19

An acid that dissociates completely in solution

Question 20

define weak acid

Answer 20

An acid that dissociates only partially in solution

Question 21

define base

Answer 21

A compound that neutralises an acid to form a salt

Question 22

define alkali

Answer 22

A type of base that dissolves in water forming hydroxide ions, OH- (aq) ions

Question 23

define a salt

Answer 23

The product of a reaction in which the H+ ions from the acid are replaced by either ammonium or metal ions

Question 24

define a redox reaction

Answer 24

A reaction involving both oxidation and reduction