Chapter 6: Ions: Charged Particles in Solution

Question 1

How are acids/bases used in food science?

Answer 1

• Food preservation

- Wine, cheese, bread making

Question 2

Define ionization.

Answer 2

Ionization is the process of forming ions.

Question 3

How does H3O+ form?

Answer 3

H atom breaks away and bonds with H2O

Question 4

How does OH- form?

Answer 4

H atom remaining in the OH group shares its electron with the O atom

Question 5

What chemical compounds are used to define acids/bases?

Answer 5

H+, H3O+, OH-

Question 6

Define acids.

Answer 6

Acids produce H+ or H3O+ in water-based solutions and have a positive charge

Question 7

Define bases.

Answer 7

Bases produce OH- in water-based solutions and have a negative charge

Question 8

Define Bronsted-Lowry’s theory.

Answer 8

• Acids/Bases separate in H2O to form ions
• Acids: proton donors
• Bases: proton acceptors
• Acids and Bases react together to produce a neutral product

Question 9

Define Lewis’s theory.

Answer 9

• Described in terms of electrons
• Bases donate electrons
• Acids accept electrons

Question 10

Name two methods to identify acids and bases.

Answer 10

1) Sensory Evaluation

2) Organic Dyes

Question 11

How do bases feel?

Answer 11

Slippery

Question 12

How do acids/bases taste?

Answer 12

Acids: sour
Bases: bitter

Question 13

What colour does Litmus paper become for bases? And acids?

Answer 13

Acids: red
Bases: blue

Question 14

How does a base affect a green vegetable?

Answer 14

Green vegetables turn brighter if a base is added

Question 15

Name the 3 ways to measure acids and bases.

Answer 15

1) pH scale
2) Titration
3) Indicators/Organic Dyes

Question 16

What does the pH scale measure?

Answer 16

The degree of (H+) or (H3O+) ions present in a solution

Question 17

What do indicators do?

Answer 17

Demonstrate the degree of acidity of a solution through colour change

Question 18

How does titration work?

Answer 18

• Adding an acid (known pH) to an unknown base or the opposite and observe for a colour change

Question 19

What do we need to calculate for a titration?

Answer 19

When the colour changes, calculate how many acid molecules it took to neutralize the base molecule

Question 20

Define the endpoint/equivalence point.

Answer 20

Where neutralization occurs (acid/base molecules are equal)

Question 21

What does titration require?

Answer 21

Knowing the volume and concentration of a solution

Question 22

What is a mole?

Answer 22

Avogadro’s number of particles of any substance

Question 23

What is molarity?

Answer 23

moles/L

Question 24

Name some roles of buffers.

Answer 24

• Maintaining blood pH

- Coating aspirin (helps digestion and prevents damage to the digestive system)

Question 25

What are Tums?

Answer 25

Antiacids -> neutralize acids for heartburn

Question 26

What can a more basic stomach lead to?

Answer 26

++ chances of contaminating substances to survive

Question 27

What is a great way to preserve food?

Answer 27

Low pH

Question 28

What is botulism?

Answer 28

Caused by a toxin that affects low-acid foods with a pH above 4.6 (dealdy)

Question 29

When does yeast grow? Mold?

Answer 29

Yeast: 4.0-7.0 Mold: 2.0 to 8.5

Question 30

How do salts work to preserve food?

Answer 30

Dehydration

Question 31

What does pH affect in baking?

Answer 31

Colour, flavour, texture

Question 32

What is a chemical leavening agent?

Answer 32

Acid and a base that neutralizes batters and doughs to lighten or aerate baked products

Question 33

How does baking soda work?

Answer 33

Salt base that needs an acidic ingredient to produce CO2 for leavening

Question 34

How does baking powder work?

Answer 34

Leavens when liquid is added and again when the mixture is heated

Question 35

What is baking powder made of?

Answer 35

Baking soda, dry acids and a filler

Question 36

Give an example of how pH affects angel food cake

Answer 36

Acids are added to angel food cake to increase the white color

Question 37

How does pH affect chocolate cake?

Answer 37

Chocolate cakes have a deeper, darker colour and smoother flavour if the batter is more basic

Question 38

What happens to the pH of eggs over time? Why?

Answer 38

Eggs become more basic in storage as CO2 escapes through the egg shell

Question 39

Mousse, soufflés and meringues need fresh eggs, why?

Answer 39

Need fresh eggs because their thicker egg whites trap more air

Question 40

What happens when fruit matures?

Answer 40

Acids develop that improve juice quality, affect colour, and increase sugar content

Question 41

Why do we need to test the pH of fruit?

Answer 41

Helps determine the ideal harvest time

Question 42

What happens to red cabbage when it is cooked in acidity? Alkalinity?

Answer 42

Acid: red Alkaline: bluish purple

Question 43

What does pH stand for?

Answer 43

power of Hydronium ions

Question 44

Are these substances acidic or basic? | Saliva, stomach, pancreatic juice, bile, blood

Answer 44

``` Saliva: acidic Stomach: acidic Pancreatic juice: basic Bile: basic Blood: basic ```

Question 45

How can low-acid foods be preserved? How will it change the food?

Answer 45

Pickling, changes texture and flavour