(Ch.3) Matter and Energy Flashcards

1
Q

What is the definition of energy?

A

Energy: Besides matter, energy is the other major component of our universe. Like matter, energy is con- served—it can be neither created nor destroyed. Ener- gy exists in various different types, and these can be converted from one to another. Some common units of energy are the joule (J), the calorie (cal), the nutritional Calorie (Cal), and the kilowatt-hour (kWh). Chemical reactions that emit energy are said to be exothermic; those that absorb energy are said to be endothermic.
**(Capacity to do work)

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2
Q

What are three common units for energy?

A

Joules, calories, Kilowatt-hour

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3
Q

What is an endothermic reaction? Which has greater en-
ergy in an endothermic reaction, the reactants or the
products?

A

An endothermic reaction is one that absorbs energy from the surroundings. The products have more energy than the reactants in an endothermic reaction.

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4
Q

List three common units for measuring temperature.

A

Celsius, Fahrenheit, Kelvin

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5
Q

Explain the difference between heat and temperature.

A

Heat is the transfer of thermal energy caused by a temper- ature difference, whereas temperature is a measure of the thermal energy of matter.

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6
Q

What is heat capacity?

A

Heat capacity is the quantity of heat energy required to change the temperature of a given amount of the sub- stance by 1 °C.

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7
Q

Why are coastal geographic regions normally cooler

in the summer than inland geographic regions?

A

the high heat capacity of the seawater keeps the temperature in the city from dropping. In the winter, the ocean actual- ly helps to keep the city warmer, compared to an inland cities.

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8
Q

Formula for Celsius temperature to Kelvin temperature.

A

K = °C + 273

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9
Q

Classify each mixture as homogeneous or heteroge- neous.

(a) coffee
(b) chocolate sundae
(c) apple juice
(d) gasoline

A

a. homogeneous c. homogeneous

b. heterogeneous d. homogeneous

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10
Q

Classify each property as physical or chemical.

(a) the tendency of silver to tarnish
(b) the shine of chrome
(c) the color of gold
(d) the flammability of propane gas

A

a. chemical c. physical

b. physical d. chemical

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11
Q

Determine whether each change is physical or chemical.

(a) A balloon filled with hydrogen gas explodes upon contact with a spark.
(b) The liquid propane in a barbecue evaporates away because the user left the valve open.
(c) The liquid propane in a barbecue ignites upon contact with a spark.
(d) Copper metal turns green on exposure to air and water.

A

a. chemical c. chemical

b. physical d. chemical

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12
Q

Define matter

A

Matter is defined as anything that occupies space and possesses mass. It can be thought of as the physical mate- rial that makes up the universe.

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13
Q

What is matter composed of?

A

Atoms or molecules

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14
Q

What is the difference between a crystalline solid and an amorphous solid?

A

In a crystalline solid, the atoms/molecules are arranged

in geometric patterns with repeating order. In amorphous solids, the atoms/molecules do not have long-range order.

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15
Q

What is a mixture?

A

A mixture is two or more pure substances combined in variable proportions.

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16
Q

What is a pure substance?

A

Pure substances are those composed of only one type of atom or molecule.

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17
Q

What is an element? A compound?

A
  • An element is a substance that cannot be broken down into simpler substances.
  • A compound is a substance composed of two or more elements in fixed definite proportions.
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18
Q

What is the difference between a mixture and a com-

pound?

A

A mixture is formed when two or more pure substances are mixed together; however, a new substance is not formed. A compound is formed when two or more ele- ments are bonded together and form a new substance.

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19
Q

What is the definition of energy?

A

Energy is defined as the capacity to do work.

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20
Q

Expain the difference between kinetic energy and

potential energy.

A

Kinetic energy is the energy associated with the motion of an object. Potential energy is the energy associated with the position or composition of an object.

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21
Q

What are three common units for energy?

A

Three common units for energy are joules, calories, and kilowatt-hour.

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22
Q

What is an endothermic reaction? Which has greater en-
ergy in an endothermic reaction, the reactants or the
products?

A

An endothermic reaction is one that absorbs energy from the surroundings. The products have more energy than the reactants in an endothermic reaction.

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23
Q

Explain the difference between heat and temperature.

A

Heat is the transfer of thermal energy caused by a temper- ature difference, whereas temperature is a measure of the thermal energy of matter.
Heat capacity is the quantity of h

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24
Q

What is heat capacity?

A

Heat Capacity: The temperature change that a sample of matter undergoes upon absorption of a given amount of heat is related to the heat capacity of the substance composing the matter. Water has one of the highest heat capacities, meaning that it is most resistant to rapid temperature changes.

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25
Q

[THE CONSERVATION OF MASS]
An automobile gasoline tank holds 42 kg of gasoline. When the gasoline burns, 168 kg of oxygen are con- sumed and carbon dioxide and water are produced. What is the total combined mass of carbon dioxide and water that is produced?

A

2.10 * 102 kg

26
Q
[CONVERSION OF ENERGY UNITS]
 Perform each conversion. 
(a) 588 cal to joules
(b) 17.4 J to Calories
(c) 134 kJ to Calories
(d) 56.2 Cal to joules
A

a. 2.46 * 10^3 J b. 4.16 * 10^-3 Cal

c. 32.0 Cal d.2.35*10^5 J

27
Q

Perform each conversion.

(a) 25 kWh to joules
(b) 249 cal to Calories
(c) 113 cal to kilowatt-hours (d) 44 kJ to calories

A

a. 9.0 * 107J b. 0.249 Cal

c. 1.31 * 10-4 kWh d. 1.1 * 104 cal

28
Q

An adult eats food whose nutritional energy totals approximately 2.2 * 103 Cal per day. The adult burns 2.0 * 103 Cal per day. How much excess nutri- tional energy, in kilojoules, does the adult consume per day? If 1 lb of fat is stored by the body for each 14.6 * 103 kJ of excess nutritional energy consumed, how long will it take this person to gain 1 lb?

A

8 x 10^2kJ; 17 days

29
Q

Determine whether each process is exothermic or endothermic.

(a) gasoline burning in a car
(b) isopropyl alcohol evaporating from skin
(c) water condensing as dew during the night

A

a. exothermic, - (Change in) H

b. endothermic, + (Change in) Hc. exothermic, - (Change in) H

30
Q

[CONVERTING BETWEEN TEMPERATURE SCALES]
Perform each temperature conversion.
(a) 212 °F to Celsius (temperature of boiling water)

A

a. 1.00 x 10^2 °C

31
Q

Perform temperature conversion.

b) 77 K to Fahrenheit (temperature of liquid nitrogen)

A

b. -3.2 x 10^2 °F

32
Q

[ENERGY, HEAT CAPACITY, AND TEMPERATURE CHANGES]

Calculate the amount of heat required to raise the temperature of a 65-g sample of water from 32 °C to 65 °C.

A

9.0 x 10^3 J

33
Q

When 56Joules of heat are added to 11 g of a liquid, its temperature rises from 10.4 °C to 12.7 °C. What is the heat capacity of the liquid?

A

2.2 J/g celsius

34
Q

Calculate the final temperature of 245 mL of water initially at 32 °C upon absorption of 17 kJ of heat.

A

49 °C

35
Q

What is the temperature change in Celsius when 29.5 L of water absorbs 2.3 kWh of heat?

A

67 °C

36
Q

A water heater contains 55 gal of water. How many kilowatt-hours of energy are necessary to heat the water in the water heater by 25 °C?

A

6.0 kWh

37
Q

A backpacker wants to carry enough fuel to heat 2.5 kg of water from 25 °C to 100.0 °C. If the fuel he carries produces 36 kJ of heat per gram when it burns, how much fuel should he carry? (For the sake of simplicity, assume that the transfer of heat is 100% efficient.)

A

22 g of fuel

38
Q

The wattage of an appliance indicates the average power consumption in watts (W), where 1 W = 1 J/s. What is the difference in the number of kJ of energy consumed per month between a refrigeration unit that consumes 625 W and one that consumes 855 W? If elec- tricity costs $0.15 per kWh, what is the monthly cost difference to operate the two refrigerators? (Assume 30.0 days in one month and 24.0 hours per day.)

A

5.96 x 10^5 kJ; $25

39
Q

What temperature is the same whether it is ex- pressed in the Celsius or Fahrenheit scale?

A

-40°

40
Q

What is matter?

A

Matter: Matter is anything that occupies space and has mass. It is composed of atoms, which are often bonded together as molecules. Matter can exist as a solid, a liquid, or a gas. Solid matter can be either amorphous or crystalline.

41
Q

What does the law of conservation of mass state?

A

Conservation of Mass: Whether the changes in matter are chemical or physical, matter is always conserved. Ina chemical change, the masses of the matter undergoing the chemical change must equal the sum of the masses of matter resulting from the chemical change.

42
Q

What is temperature?

A

Temperature: The temperature of matter is related to the random motions of the molecules and atoms that compose it—the greater the motion, the higher the tem- perature. Temperature is commonly measured on three scales: Fahrenheit (°F), Celsius (°C), and Kelvin (K).

43
Q

Formula to Convert Celsius to Fahrenheit

A

F=9/5(°C) + 32

44
Q

What is the difference between a homogeneous mixture and a heterogeneous mixture?

A

In a heterogeneous mixture: composition varies from region to region, in a homogeneous mixture: composition is uniform throughout entire mixture.

45
Q

Matter may be a ______ or a _______.

A

Pure substance or a Mixture

46
Q

A Pure Substance may be a ______ or a _______.

A

Element or a Compound

47
Q

A Mixture may be a ______ or ______

A

Heterogeneous or Homogeneous

48
Q

What is a Physical Property?

A

A property that a substance displays without changing its composition.

49
Q

What is a Chemical Property?

A

A property that a substance can display only by changing its original make up (composition).

50
Q

What are two types of changes that can occur in matter? What is the definition of each?

A

Physical Change: matter changes its appearance but not its composition.
Chemical Change: matter does change its composition.

51
Q

What is a state change?

A

Transformation from one state of matter to another ( such as solid to liquid)

52
Q

Name the two parts of chemical reactions.

A

Reactants and Products

53
Q

Burning (combustion) is what kind of change?

A

Chemical reaction

54
Q

What is an exothermic reaction? Which has greater energy in an exothermic reaction, the reactants or the
products?

A

An exothermic reaction releases energy from the system to its surroundings.
In this type of reaction, the reactants have more energy than the products because energy is released because of the reaction between the reactants.

55
Q

What is an endothermic reaction? Which has greater energy in an endothermic reaction, the reactants or the
products?

A
  • An Endothermic reaction absorbs energy from its surroundings into the system.
  • In an Endothermic reaction, the products contain more energy than the reactants because energy is absorbed as the reaction occurs.
56
Q

What is the law of conservation of energy?

A

Energy cannot be created nor destroyed.

Can change from one form to another or transferred.

57
Q

What is Work?

A

Result of a force acting on a distance

58
Q

1 calorie (cal) is = to how many joules

A

1 calorie = 4.184 joules (J)

59
Q

1 Calorie(Cal) is equal to how many calories(cal)?

A

1 Cal = 1000cal

60
Q

1 kilowatt- hour(kWh) = how many joules?

A

3.60 x 10^6 joules (J)

61
Q

Define Electrical, Thermal, and Chemical Energy:

A

Electrical : Energy associated with electrical charge.

Thermal: Energy associated with random motion of atoms and molecules. The hotter the object, the more thermal energy it has.

Chemical: Energy from chemical reactions that is associated with the position of the particles that make up the reaction

62
Q

Formulas to convert from:
> Celsius to Kelvin
> Fahrenheit to Celsius

A
K = C + 273.15
C = (F-32)/1.8