Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

1) Introduction to Food Science > Chapter 5: Energy: Matter in Motion > Flashcards

Chapter 5: Energy: Matter in Motion Flashcards

You may prefer our related Brainscape-certified flashcards:
Gourmet Food flashcards Biology 101 flashcards
1
Q

Define energy.

A

The ability to do work.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are 2 things that food scientists examine relating to energy?

A
  • How heat is transferred during cooking and preservation

- How energy affects the structure of food during such processes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Define potential energy.

A

Stored energy; the work done in lifting objects to a position

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What form is Ep in food?

A

Chemical potential energy (calories)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Define kinetic energy.

A

Energy of motion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How does Ek relate to food?

A

Atoms and molecules always in motion

ex: heat water, atoms move faster, Ek increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Compare internal vs. external energy.

A

External: E applied to an object by another source
Internal: E contained in an in an object

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What kind of energy does food contain?

A

Internal potential energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Name the 5 forms of energy in the food industry.

A

1) Mechanical
2) Electrical
3) Radiant
4) Nuclear
5) Chemical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Define mechanical energy.

A

Total kinetic and potential energy of a system.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How does the body use mechanical energy?

A

When it moves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How does the food industry use mechanical energy?

A

Food processing, for its equipment

ex: mixers, blenders, and food processors convert electrical energy to mechanical energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Define chemical energy.

A

Generated when bonds are broken/formed during chemical reactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is an endothermic reaction?

A

Absorbs energy and lowers temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is an exothermic reaction?

A

Releases energy and increases temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How does metabolism allow us to utilize chemical energy?

A

Breaks down food –> release chemical energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Define electrical energy.

A

Produced by the movement of electrons.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

During food processing, what is electric energy converted to?

A

Mechanical or radiant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is electrical energy transported by?

A

Transported through materials that are good conductors (copper, silver, etc.)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Define radiant energy.

A

Energy transmitted in the form of waves through space or some medium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is another word for radiant energy?

A

Electromagnetic spectrum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Name some examples of radiant energy.

A

Radio waves, ultraviolet waves, microwaves, electric coils, charcoal grills, gas flames, induction cooktops

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What forms of energy do microwave ovens convert?

A

Electrical energy to radiant energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How do microwaves work?

A

Electron tube converts electrical E into waves of radiant energy (microwaves). Then, the interior surfaces reflects microwaves towards the food which heats it up.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Name 3 issues with microwaves.

A
  • Food-borne outbreaks (ex: raw poultry)
  • Food not cooked properly
  • Carry-over cooking (food still being cooked after microwaving)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

How does induction cooking work?

A

Alternating currents –> magnetic field excites electrons -> electric current -> causes flat pan to heat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Why do induction cooktops produce less energy waste?

A

Since they directly heat the cooking vessel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What type of vessel needs to be used for induction cooking?

A

Ferromagnetic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Define nuclear energy.

A

Result of splitting or combining atoms of certain elements, which then give off radiation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

How is nuclear energy used in medicine?

A

X-Rays

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

How is nuclear energy used in food preservation?

A

Irradiation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Is irradiation effective? Why don’t we use it often?

A

One of the most effective, but public thinks food will be radioactive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Define heat.

A

Heat is an energy transfer from one body to another caused by a temperature difference between the 2.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Define a calorie.

A

One calorie is the heat needed to raise the temp of one gram of water one oC.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Define a kilocalorie. Why do we use kilocalories?

A

One kilocalorie is the heat needed to raise the temp of one kilogram of water one oC.
It simplifies calorie count

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Define heat capacity.

A

The ability of a substance to absorb heat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What foods have high heat capacity?

A

Foods with high water content

38
Q

Define specific heat.

A

The ability of a substance to absorb or transfer heat compared to water’s ability.
The amount of energy needed to raise the temperature of 1g of that substance 1oC.

39
Q

Why is it important to know specific heat?

A

Helps predict how the food will react during processing

40
Q

Define temperature.

A

The measure of the average kinetic energy of a group of individual molecules.

41
Q

Temperature is an indirect measure of what?

A

Molecular motion

42
Q

What is temperature measured with?

A

Thermometer

43
Q

Why is it important to measure the temperature of food?

A

To ensure food safety and product quality

44
Q

How does heat flow?

A

Hot objects –> cold objects

45
Q

What does thermodynamics study?

A

Studies heat flow and T in relation to material properties

46
Q

Name the 3 types of heat transfers.

A

1) Conduction
2) Convection
3) Radiation

47
Q

Define conduction.

A

Transfer of heat through matter from particle to particle collisions

48
Q

Where does conduction occur?

A

Only in metals at the molecular level

49
Q

What happens to electrons during conduction?

A

Heated electrons skip over tens of hundreds of atoms and speed the heat transfer

50
Q

Define convection.

A

Transfer of heat by the motion of molecules within a liquid or a gas (water or air)

51
Q

Is conduction or convection faster?

A

Convection

52
Q

Give a common example of convection.

A

Cooking food in water

53
Q

Define radiation.

A

Transfer of heat by electromagnetic waves (browning).

54
Q

What doesn’t radiation need?

A

The presence of matter

55
Q

Give examples of radiation.

A

Browning of baked goods, roasted foods, broiling, rotisserie cooking, solar oven

56
Q

What do phase changes need?

A

A flow of energy

57
Q

Gas to Solid

A

Deposition

58
Q

Solid to Gas

A

Sublimation

59
Q

Liquid to Gas

A

Evaporation

60
Q

Gas to Liquid

A

Condensation

61
Q

Solid to Liquid

A

Fusion

62
Q

Liquid to Solid

A

Crystallization

63
Q

What is the energy needed to melt/freeze called?

A

Latent heat of fusion

64
Q

What is the energy needed to evaporate/condense called?

A

Latent heat of vaporization

65
Q

What is the energy needed to complete rearranging of molecules during phase change called?

A

Latent heat

66
Q

How is the temperature at the point of a phase change?

A

T remains constant

67
Q

Why is understanding phase changes important?

A

Important in processing and preserving food products

68
Q

Name the 3 factors that affect rates of reaction in food preparation.

A

1) Temperature of reactants
2) Amount of surface area
3) Thickness of food

69
Q

If a child is swinging, the fastest speed will be at the bottom of the swinging motion when maximum ____ is reached and slowest speed at the top of the swinging motion when maximum ___ is reached.

A

Ek

Ep

70
Q

If you are sitting perfectly still, your body has _____ energy.
If a friend pulls you out of your chair, your body has ____

A

External potential energy

External kinetic energy

71
Q

Where is the internal kinetic energy in your body? Internal potential energy?

A

Kinetic: molecules within body are moving and doing work
Potential: fat stored as fuel for work

72
Q

A waterwheel is a form of ____ energy

A

Kinetic mechanical energy

73
Q

Making homemade ice cream by mixing salt and ice is a ____ reaction

A

endothermic reaction, lowers temperature

74
Q

Digestion is an _____ reaction

A

exothermic

75
Q

Dissolving NaOH in water is an ____ reaction

A

exothermic

76
Q

What is visible radiant energy called?

A

Light

77
Q

How do microwaves cook food?

A

Microwaves cause polar compounds to vibrate. This causes friction which produces heat.

78
Q

What kinds of foods will cook faster in a microwave?

A

Foods with high water content, or foods that are high in fats and sugar (help conduct heat)

79
Q

What are the advantages of induction cooktops?

A
  • Can boil water in half the time of gas and electric stoves

- Surface of the cooktop stays relatively cool

80
Q

Why is grilling not seen as healthy?

A

Carcinogens are formed when meats are grilled

81
Q

Why is water a great cooking medium?

A

High heat capacity, rapidly absorb heat or transfer it

82
Q

Would a glass of water and a pitcher have the same heat? And temperature?

A

Temp: same
Heat: different because different masses
–> measure of all the kinetic energy

83
Q

When temperature is the same between two objects, how does heat flow?

A

It stops

84
Q

What type of heat transfer is a pan touching a heat source? When will the heat transfer stop?

A

Conduction

When heat source, pan, and food have the same temp

85
Q

What type of heat transfer is cooking food in water or baking? When will the heat transfer stop?

A

Convection

When the fluid is the same temperature throughout

86
Q

Frost forming on a window in a cold morning is an example of what phase change?

A

Deposition

Water vapor –> solid state

87
Q

Gas rising from dry ice is an example of what phase change?

A

Sublimation

88
Q

What phase change is used to freeze and dry foods at the same time? ex: freeze dried coffee

A

Sublimation

89
Q

If a substance is being cooled, latent heat is being ______. This occurs during ______

A

released

crystallization, condensation, deposition

90
Q

If a substance is being heated, latent heat is being ______. This occurs during ______

A

absorbed

melting, vaporization, sublimation

91
Q

T or F: The rate of a reaction approximately doubles for every 10oC increase in temperature

A

True

1) Introduction to Food Science (20 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions