Exam Practice 2

Question 1

What is pH ?

Answer 1

It provides information about H+ and OH- concentrations in dilute aqueous solutions

Question 2

What does acid produce when dissolved in water ?

Answer 2

It produces H+ when dissolved in water .

Question 3

A base is a substance that produces OH -

Answer 3

When dissolved in water

Question 4

What is the H+ and OH+ concentrations are equal to 0.7?

Answer 4

True

Question 5

What happens to H+ concentration when the pH decreases ?

Answer 5

It increases the H+ concentration and the pOH increases and the OH- decreases.

Question 6

What is the molarity of 0.05 moles of sodium chloride in 0.05 litres ?

Answer 6

Using the equation = moles /volume(LITRES).

0.05moles divided by 0.5 litres =10 M

Question 7

What is the molarity of 0.09 moles of sodium sulphate in 12 mL of solution ?

Answer 7

Using the equation =moles/vol

12 ml divided by 1000=0.012L

0.09 divided by 0.012 = 7.5 M

Question 8

What is the molarity of 0.75 moles of Lithium Fluoride in 65 mL of solution ?

Answer 8

Using the equation =moles/vol

65 divided by 1000= 0.065L
0.75 divided by 0.065 =11.5 M

Question 9

What is the molarity of 120 grams of calcium nitrite Ca(NO2)2 in 240 mL of solution?

Answer 9

Using the equations :
1.Mass(g)=Moles x RFM
2 .moles/vol

240 divided by 1000=0.24L
Mr=164
Moles = 120 grams divided by 164 =0.73
0.73 divided by 0.24 =3.04

Question 10

What is the molarity of 45 grams of Ammonia NH3 in 0.75 L of Solution ?

Answer 10

Using the equation
1.Mass(g)=Moles x RFM
2 .moles/vol

NH3 = 14+1 x3 =17.031
45 grams divided by 17.=2.64705882
2.64705882 divided by 0.75 L=3.52 -3.53 M

Question 11

What is the Molar Concentration of 120 grams of Ca(N02)2 in 240 mL of Solution ?

Answer 11

Using the equations :
Molarity (M)= Moles /Vol(Litres)

1. 240 divided by 1000 =0.24L
2. Cano2=132
3. 120 divided by 132=0.09 moles
4. 0.09 divided by 0.24 =3.79 M

Question 12

What is the Molar concentration of 140 grams of Nh30 in 360 ml of solution ?

Answer 12

1. Mass(g)=Moles x RFM
2. .moles/vol

1, 360 divided by 1000=0.36

2. NH30= 14 + (1X3)+16 = 14+3 +16 =33
3. 140 divided 33 = 4.24 moles
4. Moles =4.24 divided by 0.36=0.12M

Question 13

Dilutions Question

If I add 25 mL of water to 125 mL of a 0.15 M NaOH solution, what will the molarity of the diluted solution be?

Answer 13

If I add 25 mL of water to 125 mL of a 0.15 M NaOH solution, what will the molarity of the diluted solution be?

C1V1 = C2V2

(0.15 M)(0.125 L) / (0.15 L) = C2 C2 = 0.125 M
C1 x V1 / V2

C2=0.125 M

Question 14

If I add water to 100 mL of a 0.15 M NaOH solution until the final volume is 150 mL, what will the molarity of the diluted solution be?

Answer 14

C1V1 = C2V2

(0.15 M)x(0.1 L) / (0.15 L) = C2

C2 = 0.100 M

Question 15

How much 0.05 M HCl solution can be made by diluting 250 mL of 10 M HCl?

Answer 15

C1V1 = C2V2

(10 M)x(0.25 L) / (0.05 M) = V2 V2 = 50 L

Question 16

I have 345 mL of a 1.5 M NaCl solution. If I boil the water until the volume of the solution is 250 mL, what will the molarity of the solution be?

Answer 16

C1V1 = C2V2

(1.5 M)x(0.345 L) / (0.250 L) = C2

C2 = 2.07 M

Question 17

What does the Hydroxyl group contain ?

Answer 17

They contain OH or can be written as H0

Ethanol the alcohol present in alcoholic beverages .

Its polar due to electronegative oxygen forms .Hydrogen bonds with water helping dissolve compounds such as sugars .

Question 18

What does Carbonyl contain ?

Answer 18

C=0 either pointing upwards or downwards

Ketone ro Aldehydes : Compounds names

both within carbon groups
Aldehydes are at the end of the chain whilset ketones middle for example.

Acetone : Simplest ketone
Propanol is an aldehyde due to being in the carbonyl group

Question 19

What does Carbonyl group two contain ? 2

Answer 19

C00H
Acts as a acid and can donate H+ because the covalent bond between oxygen and hydrogen is polar .

Compund name : Carboxylic acid

Question 20

What is Amino acids group ?

Answer 20

• NH2 N - H =H
  Acts as a base picks up H+ from surrounding solution

Amine compound name

Question 21

Methyl Group ?

Answer 21

Affects the expression of genes when on DNA or on proteins bound to DNA affecting the shape and function of male and female sex hormones

Compound name : Methyl compound

Outside as CH3