Chapter 4 acid and redox

Question 1

What is the formula for phosphoric acid?

Answer 1

H3PO4

Question 2

What is the formula for nitric acid?

Answer 2

HNO3

Question 3

What is the formula of sulfuric acid ?

Answer 3

H2SO4

Question 4

What is the formula of hydrochloric acid?

Answer 4

HCl

Question 5

What happens to acids when dissolved in water?

Answer 5

They have free moving H+ ions

Question 6

Define acids

Answer 6

A compound that releases hydrogen ions (H+ protons) in aqueous solution

Question 7

A strong acid fully …….. in aqueous solution to release ……. ions

Answer 7

Disassociates

H+

Question 8

A weak acid will ……. dissociate in aqueous solution

Answer 8

Partially

Question 9

What are bases?

Answer 9

Metal carbonate
Metal hydroxides
Metal oxides
Ammonia
Amine

A substance that accepts hydrogen ions from an acid

Question 10

What is an alkali ?

Answer 10

A soluble base. A compound that gives a solution with a pH greater than 7 when dissolved in water. It releases OH- in aqueous solutions

Question 11

A strong alkali will

Answer 11

Undergo complete dissociation

Question 12

What is the ionic equation for neutralisation?

Answer 12

H+ + OH- ——> H20

Question 13

What are spectator ions in a neutralisation reaction?

Answer 13

Any ions that are not H+ or OH-

Question 14

Acid + base——>

Answer 14

Salt and water

Question 15

Acid+alkali ——->

Answer 15

Salt + water

Question 16

Acid + metal carbonate ———>

Answer 16

Salt + water + carbon dioxide

Question 17

Acid + metal ——>

Answer 17

Salt + hydrogen

Question 18

Define concordant results

Answer 18

Results within 0.1cm3 of each other

Question 19

What is the importance of rinsing a conical flask with distilled water while using it for a titration ?

Answer 19

Ensures all acid/alkali/ reactants are in the solution as it couldve been in the sides of the flask

Question 20

Why does adding distilled water to the conical flask not change the concentration value?

Answer 20

The added water doesnt change the number of moles of acid/alkali in the solution so the concentration doesnt change

Question 21

State why it is important to fill the space below the tap in the Burrett with solution before beginning an accurate titration?

Answer 21

The space will fill during the titration so the volumes added are too low

Question 22

Suggest why a 250cm3 conical flask is preferred to a 250cm3 beaker for titrations

Answer 22

Less chance of loosing liquid on swirling

Question 23

State the calculation to work out the concentration of a solution in moldm-3

Answer 23

Moles/volume (dm3)

Question 24

What is the equation for working out the concentration of a solution in gdm-3?

Answer 24

Mass/volume (dm3)

Question 25

How do you convert from moldm-3 to gdm-3?

Answer 25

Multiply by Mr

Question 26

State the percentage uncertainty equation

Answer 26

Maximum uncertainty/value of measurement

X100

Question 27

State the method for preparing a standard solution

Answer 27

Weight the solid accurately in a weighing boat on scales and pour into a beaker.
Wash the boat with distilled water and add rhe washings to the beaker
Get a 250cm3 volumetric flask and place a funnel in it
Transfer solution to flask
Wash beaker, funnel and glass rod and add washings to flask
Fill flask with distilled water until the bottom of the miniscus reaches the graduation mark
Invert several times