Lab 1

Question 1

What is the relationship between pH and molar ratio?

Answer 1

pH = pka+log[base]/[acid]

pH and molar ratio have a direct relationship. pH increases as [base]/[acid] increases

Question 2

What is the molar ratio of [base]/[acid] when pH=pka?

Answer 2

molar ratio [base]/[acid] = 1/1

Question 3

HCl is a strong acid. What is the pH of a 2millimolar HCl solution?

Answer 3

pH = -log[H+]
2millimole = 0.002 Molar
-log[0.002]

pH=2.70

Question 4

What is the pH of a 0.2millimolar sodium hydroxide solution?

Answer 4

sodium hydroxide = STRONG BASE

0.2 millimolar = 0.0002molar
pOH= -log[0.0002]
pOH=3.70
pH= 14-3.70
pH = 10.3

Question 5

Differentiate between dissociation and ionization

Answer 5

Differentiation is a process in which a molecule dissociates into 2 or more components. Ionization is when the products of the dissociation are charged ions

Question 6

What is pH? Does pH increase or decrease when sodium hydroxide is added to water?

Answer 6

pH defined as the negative log of the hydrogen ion concentration. pH will increase when sodium hydroxide is added to water (more basic)

Question 7

What are electrolytes?

Answer 7

Compounds that form charged ions in water and thus enable water to conduct electricity

Question 8

How are electrolytes classified?

Answer 8

Based on their degree of ionization in DILUTE solutions

Question 9

Strong electrolytes dissociate _____ in dilute solutions

Answer 9

completely

Question 10

Weak electrolytes dissociate ____ in dilute solutions

Answer 10

partially

Question 11

Non electrolytes….

Answer 11

do not ionize in water

Question 12

What are some examples of non electrolytes?

Answer 12

ethanol, glycerol, glucose, sucrose

Question 13

Water is a ____ electrolyte

Answer 13

poor

Question 14

Acetic acid is a ___ electrolyte

Answer 14

weak

Question 15

Sodium chloride is a ____ electrolyte

Answer 15

strong

Question 16

Dissociation/Ionization reactions of weak electrolytes….

Answer 16

occur in forward and backward reactions until equilibrium is reached

Question 17

Ka=

Answer 17

[H3O+] * [A-]/
[H2O] (ignored in dilute solutions)

Question 18

Ka is the..

Answer 18

acid dissociation constant

Question 19

Kb is the….

Answer 19

base dissociation constant

Question 20

Kb=

Answer 20

[BH+] * [OH-]/
[B] *[H2O] (ignored in dilute solutions)

Question 21

Bronsted lowry base theory describes an acid as….

Answer 21

A compound that donates a proton

Question 22

In LEWIS acid base theory….

Answer 22

Bases donate a pair of electrons and acids accept a pair of electrons

Question 23

[HA] + [H2O] eq [H3O+] + [A-]

What is the conjugate base of [HA]?

Answer 23

[A-].

Question 24

[B] + [H2O] eq [BH+] + [OH-]

What is the conjugate acid of [B]?

Answer 24

[BH+]

Question 25

water is ______, meaning it can behave as an acid or a base

Answer 25

amphiprotic/amphoteric

Question 26

[H2O] eq [OH-] + [H+]

What is the Keq for water?

Answer 26

[OH-] * [H+]/
[H2O]

Question 27

pKa=

Answer 27

-log[Ka]

Question 28

The lower the pka……

Answer 28

the higher the acidity

Question 29

The higher the Ka….

Answer 29

The higher the acidity

Question 30

When pH=pka, what does that say about acid-base ratio?

Answer 30

acid and base are both 50% ionized

Question 31

Phosphoric acid is a ___ acid, meaning that….

Answer 31

triprotic. it can donate 3 protons

Question 32

Compare H2PO4^-1 vs ^-2 vs ^-3

Answer 32

^-1 = very weak acid
^-2=extremely weak acid
^-3 = base

Question 33

When pH = pka, the dilution factor is..

Answer 33

10

Question 34

When molar ratio is 1, what is the log molar ratio?

Answer 34

log(1) = 0

Question 35

When molar ratio is 1/10, what is log molar ratio?

Answer 35

log(0.1) = -1