Acids and Bases

Question 1

Define Acid

Answer 1

substances that produce H⁺ ions

Question 2

Name 3 examples of acids

Answer 2

H₂SO₄ , HNO₃ , HCl , H₃PO₄

Question 3

Fill in the blanks:

In solutions, acids produce a pH ___ at rtp.

Answer 3

< 7

Question 4

Are Non-metal oxides acids or bases?

Answer 4

acids

Question 5

What happens when an acid dissociates?

Answer 5

it produces H⁺ ions which is what makes a solution acidic.

Question 6

What happens when a non-metal oxide reacts with water?

Answer 6

forms an acid

Question 7

Where do acids produce H⁺ ions?

Answer 7

ONLY IN WATER

Question 8

Why is HCl either an acid or neutral depending on the type of bonding it has?

Answer 8

If HCl has ionic bonding, it can dissolve in water, therefore dissociating to release H⁺ ions which is what makes a solution acidic.

If HCl has covalent bonding, it is insoluble in water so no H⁺ ions can be released because they can dissociate.

Question 9

Define bases

Answer 9

substances that react with acids to form water

Question 10

What ion do most bases produce in water?

Answer 10

OH⁻

Question 11

Define neutralisation reaction

Answer 11

when an acid and a base react to produce water

Question 12

acid + base →

Answer 12

salt + water

Question 13

NH₃ + H₂O →

Answer 13

NH₄OH (ammonia)

Question 14

NH₄OH → (dissociated)

Answer 14

NH₄ + OH⁻

Question 15

Define alkali

Answer 15

base which dissolves in water, specifically group 1 metal hydroxides / carbonates

Question 16

What does the pH >7 (if the base dissolves) measure?

Answer 16

the concentration of acids / bases

Question 17

Define Ionic equation

Answer 17

an equation that only shows the change in chemicals

Question 18

What has to happen in order for a neutralisation reaction to react a pH of 7?

Answer 18

the acid and the base have to react in equal molar quantities (H⁺ + OH⁻)

Question 19

What is the logarithmic scale for pH?

Answer 19

The scale where e.g. pH 3 is ten times more acidic than pH 4 and pH 3 is 100 times more acidic than pH 5. Likewise, pH 11 is 10 times more basic than pH 10.

Question 20

THE PH DOES NOT DIRECTLY RELATE TO THE DANGER OF AN ACID/BASE

Answer 20

ok…

Question 21

What does concentration measure?

Answer 21

the moles of a substance dissolved in a specific volume of solvent (water)

Question 22

What is the unit of concentration?

Answer 22

mol / dm³ ⤵
↓ volume
moles of
of solvent
solute

Question 23

1 dm³ =

Answer 23

1,000 cm³

Question 24

Fill in the blanks: The concentration of an acid is a measure of the _____________________ dissolved in any solvent.

Answer 24

number of moles

Question 25

What is the difference between the strength of an acid and the concentration of an acid?

Answer 25

The concentration of an acid is a measure of the number of moles dissolved in any solvent. Any acid can have any concentration. The strength of an acid is an inherent / fixed property of an acid.

Question 26

What does the strength of an acid measure?

Answer 26

the degree of dissociation

Question 27

stronger acid =

Answer 27

= higher degree of dissociation

Question 28

Pick the correct word: 1. Stronger / Weaker acids effervesce more and faster and have a higher temp. increase when reacting with a metal. 2. Stronger / Weaker acids effervesce more and faster and have a slight higher temp. increase when reacting with a metal carbonate. 3. When reacting with metal hydroxides, the temp. increases less in stronger / weaker acids . 4. a) When testing for electrical conductivity, H₂ effervesces at the cathode and Cl₂ effervesces at the anode (5 amps) in stronger / weaker acids. b) H₂ effervesces at the cathode and Cl₂ effervesces at the anode (1 amps) in stronger / weaker acids.

Answer 28

1. Stronger 2. Stronger 3. Weaker 4. a) stronger b) weaker

Question 29

Fill in the blanks: During conduction, ions are ________ and then replaced by _____________________. ask mr.bow

Answer 29

During conduction, ions are used up and then replaced by the undissociated molecules.

Question 30

Define titration

Answer 30

the method used to accurately measure the concentration of a solution

Question 31

What does a volumetric pipette do?

Answer 31

accurately measures (only) one volume (unknown chemical)

Question 32

What does a burette do?

Answer 32

less accurately measures any volume, can add chemicals in small sections (known chemical)

Question 33

What is the general method for titration?

Answer 33

1) clean pipette with water 2) clean pipette with intended solution 3) measure 25cm³ of NaOH into conical flask 4) add indicator (2 drops) 5) clean burette with water 6) clean burette with HCl 7) fill burette and write down initial reading 8) add HCl (little bit at a time) until HCl goes colorless 9) repeat until concordant results (within 0.1 cm³)