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

Answer 2

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

Question 3

How do you make a standard solution?

Answer 3

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 4

How many decimal places does a burette reading have?

Answer 4

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 5

Describe the procedure of an acid base titration

Answer 5

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 6

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

Answer 6

Sum of the oxidation numbers

Question 7

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

Answer 7

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

Question 8

What is the oxidation number of H in metal hydrides?

Answer 8

-1

Question 9

What is the oxidation number of O in peroxides?

Answer 9

-1

Question 10

What do the Roman numerals in compounds mean?

Answer 10

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

Question 11

Describe oxidation and reduction in terms of oxygen

Answer 11

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

Question 12

Describe oxidation and reduction in terms of electrons

Answer 12

Oxidation is losing, reduction is gaining (OIL RIG)

Question 13

Describe oxidation and reduction in terms of oxidation numbers

Answer 13

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

Question 14

define an acid

Answer 14

a species that releases H+ ions in solution

Question 15

define strong acid

Answer 15

An acid that dissociates completely in solution

Question 16

define weak acid

Answer 16

An acid that dissociates only partially in solution

Question 17

define base

Answer 17

A compound that neutralises an acid to form a salt

Question 18

define alkali

Answer 18

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

Question 19

define a salt

Answer 19

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

Question 20

define a redox reaction

Answer 20

A reaction involving both oxidation and reduction

Question 21

Not reactive metal + steam

Reactive metal + water

Answer 21

1) Metal oxide + hydrogen

2) Metal hydroxide + hydrogen