Air

Front 1

Define the following term:

Humidity

Back 1

The moisture content of air

Front 2

Define the following term:

Absolute humidity

Back 2

The mass of water vapor contained in a certain volume of air

Front 3

Define the following term:

Relative humidity

Back 3

The ration of the mass of water vapor in the air at a given temperature to the maximum mass of water vapor the air could hold at that temperature, expressed as a percentage.

Front 4

Define the following term:

Greenhouse effect

Back 4

The process by which certain gases (principally water vapor, carbon dioxide and methane) trap heat that radiates from earth.

Front 5

Define the following term:

Parts per million

Back 5

The number of molecules (or atoms) of a substance in a mixture for every 1 million molecules (or atoms) in that mixture.

Front 6

The temperature is the same at 1P.M. on two consecutive days. For a person who is outside working, however, the second day feels cooler than the first day. On which day was the relative humidity higher?

Back 6

The humidity is higher on the first day. Since the person felt cooler on the second day (despite the same temperature), his sweat must have evaporated more quickly than on the first day. Thus, the first day was more humid.

Front 7

A child decides to keep his goldfish outside in a small bowl. He has to add water every day to keep the bowl full. On two consecutive days, the temperatures are very similar, but on the first day the relative humidity is 90%, while on the second day it is 60%. On which day will the child add more water to the goldfish bowl.

Back 7

The child will add more water on the second day. Since the humidity was lower on the second day, the water in the bowl will evaporate more quickly on that day.

Front 8

If you put a glass of water outside when the relative humidity is 100%, how quickly will the water evaporate?

Back 8

The water will not evaporate. Since the relative humidity is 100%, the air cannot hold any more water vapor. As a result, no net evaporation will occur.

Front 9

Why does sweating cool people down?

Back 9

Sweat cools you down because when it evaporates, it takes energy from your skin. When energy leaves you skin, it gets cooler.

Front 10

What is the percentage of nitrogen in dry air? What about oxygen?

Back 10

Dry air is 78% nitrogen and 21 % oxygen

Front 11

What would be the consequence of removing all the carbon dioxide in earth's air supply?

Back 11

If the air had no carbon dioxide in it, the earth would be colder. Since carbon dioxide is a greenhouse gas, the greenhouse effect would be weaker, leaving a cool earth. You could also answer this question by saying that plants would die of starvation.

Front 12

What would be the consequence of removing all the ozone in earth's air supply?

Back 12

If there were no ozone in the air, ultraviolet light would kill a lot of living things.

Front 13

What would be the consequence of a sudden increase the concentration of oxygen in the earth's air supply?

Back 13

If more oxygen were in the air, living things would not be as healthy and forest fires would increase in frequency and ferocity.

Front 14

Suppose astronomers found another solar system in which there was a sun just like our sun. Suppose further that a planet in this new solar system was just as far from its sun as is earth from our sun. Since the vast majority of energy that planets get comes from their suns, is it reasonable to assume that the new planet would have roughly the same average temperature as that of earth? Why or why not?

Back 14

There is no reason to expect that the new planet will have the same temperature as earth. If it does not have essentially the same air, with all the same levels of all the greenhouse gases, it will not have the same temperature! Mercury, for example, is much closer to the earth than Venus. Venus, however, is warmer than Mercury, because the greenhouse effect on Venus is very strong.

Front 15

What makes up the majority of the air we exhale?

Back 15

Nitrogen makes up the majority of the air we exhale.

Front 16

Do we exhale more carbon dioxide or more oxygen?

Back 16

We exhale more oxygen.

Front 17

Do the data indicate any significant global warming?

Back 17

No. Figure 2.6 shows that the average global temperature has been reasonably constant for the past 80 years.

Front 18

The current concentration of ground-level ozone in the air is about 0.110 ppm. What is that in percent?

Back 18

Remember, we know the relationship between ppm and percent. We can therefore just use the factor-label method to figure out the answer:

0.0000110%

Front 19

Suppose you had a sample of air in which the concentration of nitrogen oxides is 0.023%. What would the concentration of nitrogen oxides be if you expressed it in ppm?

Back 19

Remember, we know the relationship between percent and ppm, so we can convert using the factor-label method:

The concentration of nitrogen oxides in this sample of air is 230 ppm

Front 20

Suppose you left a glass of water outside on two different days. On the first day, it is warm and humid. On the second day, it is the same temperature, but the humidity is low. Each day, you measure how long it takes the water to completely evaporate from the glass. On which day will the time it takes the water to evaporate be the smallest?

Back 20

The water will take the least time to evaporate on the second day.

Hint 20

Remember, when humidity is high, there is already a lot of water vapor in the air. Thus,, water does not evaporate very quickly. On low humidity days, however, there is little water vapour in the air, so water evaporates quickly

Front 21

Suppose you did the same experiment that was described in the previous problem, when the relative humidity was 100%. How quickly would the water evaporate from the glass?

Back 21

You will not see any evaporation from the glass of water.

Hint 21

When the relative humidity is 100%, no more water can go into the air, so no net evaporation can occur! Now it turns out that water will evaporate from the glass, but water will also condense back into the glass from the air. The rate at which the water evaporates will equal the rate at which it condenses, however, so no net evaporation will occur.

Front 22

If a scientist were to measure the percentages of nitrogen and oxygen in a sample of air that was not dry, would they be greater than, less than, or essentially the same as the percentages shown in Figure 2.1?

Back 22

The percentages of nitrogen would be less.

Hint 22

Think about this one. If there is water in the air, then the total amount of molecules in the air is greater. Well, the percentage of a substance is equal to the amount of that substance divided by the total amount in the mixture times 100. if you just add water vapor to the mixture of gases, you have not increased the amount of nitrogen, for example. Thus, the amount of nitrogen stays the same. However, the total amount of molecules in the mixture increase, because you added water molecules. As a result, when you calculate the percentage, you take the same number for the amount of nitrogen, but you divide by a larger number for the amount of molecules in the mixture). As a result, the percentage of nitrogen goes down.

Front 23

At high altitudes, there is less air around you as compared to lower altitudes. Would a candle at high altitudes burn dimmer, brighter, or essentially the same as the same candle at low altitudes?

Back 23

The candle would burn dimmer.

Hint 23

If there is less air around you, there is also less oxygen around you. With less oxygen, the fire will burn more slowly, making the candle dimmer.

Front 24

We know that if the carbon dioxide concentration were too low, plants would starve. Conversely, experiments indicate that many plants actually flourish when the concentration of carbon dioxide in their vicinity increases. How can this fact help explain why some experiments indicate that houseplants tend to grow better when their caretakers talk to them?

Back 24

Plants may grow better when their caretakers talk to them because when someone talks to a plant he exhales some carbon dioxide on it.

Hint 24

This increases the concentration of carbon dioxide in the plant’s vicinity, which might make some plants grow better.

Front 25

We know that our bodies do not use the nitrogen we inhale. Nevertheless in Figure 2.5, notice that the percentage of nitrogen in exhaled airs is lower than the percentage of nitrogen in inhaled air. If our bodies do not use nitrogen in any way, why does the percentage decrease?

Back 25

You use the same reasoning here that you used in question 2.3. Since exhaled air has more molecules in it (water vapor and carbon dioxide, for example), the percentage of nitrogen decreases not because the amount of nitrogen decreases, but because the total amount in the mixture increases.

Hint 25

Once again, the amount of nitrogen is the same in both inhaled and exhaled air. However, since there are more molecules in exhaled air, when you calculate the percentage of nitrogen in exhaled air, you take the same number and divide it by a larger number. This makes a smaller percentage.

Front 26

One popular thing to do in American politics is to note that many of the past few years have been some of the warmest ever recorded. This is then used to support the idea that global warming is happening. What is wrong with this kind of argument?

Back 26

There are at least two problems with this argument. First studies indicate that average global temperatures in the Middle Ages were warmer than they are now.

Hint 26

Thus, even though the recorded temperatures are greater now than they have been before, we know it is not warmer now than in earth’s past. If the warmer temperatures of the Middle Ages were not due to global warming, how can the current warm period that is actually cooler than the Middle Ages be a result of global warming?

The second problem is even more important. Global warming is a long term effect, and you must therefore use long-term trends in the data to support it.

Notice from the lower portion of Figure 2.6 that in the late 1930’s and the early 1950’s, the temperatures were the warmest ever on record up to that point. However, the next 30 years experienced a long-term cooling trend. As a result, the “hot” years were offset by a number of “cool” years, so there was no long-term temperature change. As a result, the “hot” years were offset by a number of “cool” years, so there was no long-term temperature change. As a result, the fact that we are experiencing a few years of extra warmth notice the data from the late 1990’s on) means nothing when it comes to global warming. If history is any indication, the earth will experience a cooling trend that will offset these slightly warmer temperatures

Front 27

One evolutionary theory of how life originated on the planet requires that, at one point, there was oxygen in the atmosphere. This theory, of course, assumes that the first life form did not breathe oxygen. Since there are organisms today that can exist without breathing oxygen, this is not as fantastic as it may first sound. Based on what you learned in this section, however, what serious objection can you raise against the theory that life originated on an earth with no oxygen in its air?

Back 27

No oxygen means no ozone. With no ozone layer, no life form would be able to exist on the surface of the earth.

Hint 27

Remember, the earth replenishes its ozone supply from its oxygen supply. With no oxygen, there would be no ozone.

Front 28

Suppose you could institute regulations that would be targeted at one specific air pollutant. Based on the data in Figure 2.9, which air pollutant would be best to target from a cost/benefit point of view?

Back 28

Nitrogen oxides would be the best pollutant to target,

Hint 28

because the concentration of nitrogen oxides is still rather high. Thus, we could probable derive a lot of benefit from reducing nitrogen oxides, It turns out this is rather hard to do, however, because nitrogen oxides are produced whenever there is a lot of heat and air, and most industries, automobiles, etc, need a lot of heat.

Front 29

Define Humidity

Back 29

The moisture content of air

Front 30

Define absolute humidity

Back 30

The mass of water vapor contained in a certain volume of air

Front 31

Define relative humidity

Back 31

The ratio of the mass of water vapor in the air at a given temperature to the minimum mass of water vapor the air could hold at that temperature, expressed as a percentage.

Front 32

Define greenhouse effect

Back 32

The process by which certain gases (principally water vapor, carbon dioxide, methane) trap heat that radiates from earth.

Front 33

Define parts per million

Back 33

The number of molecules (or atoms) of a substance in a mixture for every 1 million molecules )or atoms) in that mixture.

Front 34

When does water evaporate more slowly – under conditions of high humidity or low humidity?

Back 34

Water evaporates slowly under conditions of high humidity

Hint 34

Remember, the higher the humidity, the more water vapor that is already in the air. This makes it harder to put more water vapor in the air, which is what evaporation does

Front 35

Will sweating help cool you down when the humidity is 100%?

Back 35

No sweating will not cool you down

Hint 35

When humidity is 100%, water will not evaporate, and this is what gives sweat its cooling effect.

Front 36

What gas makes up the majority of the air we inhale?

Back 36

Nitrogen makes up the majority of the air we inhale. (See figure 2.5)

Front 37

What gas makes up the majority of the air we exhale?

Back 37

Nitrogen makes up the majority of the air we exhale.

Front 38

A chemist is monitoring the rate at which a certain substance burns. The chemist burns the substance in a fireplace4 that uses the room’s air supply. The chemist then repeats the experiment, this time in a chamber whose air mixture is 50% nitrogen. In which trial will the substance burn the fastest?

Back 38

The substance will burn the fastest in the second trial.

Front 39

Why is it important to have ozone in earth’s air?

Back 39

Ozone blocks the ultraviolet light from the sun. Without it, life could not exist on the planet.

Front 40

For good health, should we increase or decrease the concentration of ground-level ozone in the air?
Ground-level ozone concentrations should be decreased.

Remember, ozone is a poison. We do not want to breathe it. We want it all up in the ozone layer.

Back 40

Ground-level ozone concentrations should be decreased.

Hint 40

Remember, ozone is a poison. We do not want to breathe it. We want it all up in the ozone layer.

Front 41

Has the average temperature of the earth increased significantly in the past 80 years?

Back 41

No.

The average temperature of the earth has remained rather steady since 1925. See figure 2.6.

Front 42

What pollutant concentration was decreased by the mandate of catalytic converters?

Back 42

Catalytic converters reduced the concentration of carbon monoxide.

Front 43

The moisture content of air is called _______.

Back 43

humidity

Front 44

God has designed you to ________ when you are too warm.

This releases water onto your skin, which then evaporates.

Back 44

sweat

Front 45

The process of evaporation requires ________ which is supplied by your skin. As a result, when your sweat evaporates, the net effect is that your skin__________

Back 45

energy

cools down

Front 46

When the humidity is high, your sweat does not _________as quickly, and as a result, you do not cool down as well.

For this reason, many weather reports include a ______ ______ which is a combination of temperature and humidity.

Back 46

evaporate

heat index

Front 47

There are two ways of reporting humidity: ________ and __________. If you report the mass of water vapor contained in a certain volume of air, you are reporting the __________.

Back 47

relative humidity

absolute humidity

absolute humidity

Front 48

If you report the ratio of the mass of water vapor in the air at a given temperature to the maximum mass of water vapor the air could hold at that temperature, you are reporting the __________.

Back 48

relative humidity

Front 49

On a day when the relative humidity is high, water evaporates ______.

On a day when the relative humidity is low, water evaporates more _______. If the relative humidity is ______we say that the air is saturated with water.

Back 49

slowly

quickly

100%

Front 50

Dry air (air that has all of the ______ _______ removed) is 78% _____, _______ oxygen, and 1% _______. This is an _____mixture of gases to support life. The oxygen is necessary in order to allow our bodies to run _______reactions.

Back 50

water vapor
nitrogen
21 %
other gases
ideal
combustion

Front 51

Without enough oxygen, our bodies would run out of the ______necessary for life. Too much oxygen in the atmosphere, however can cause ______problems in people and significantly increase the number of natural _______.

Back 51

energy
health
forest fires

Front 52

The majority of the air we breathe in is nitrogen, and the majority of the air that we breathe out is ______.

In addition to nitrogen the other major gases we exhale are ___,____, and_____. Of those three gases, we exhale significantly more____ than he other two. _____ enters the atmosphere as a result of organisms breathing and as the result of fires.

Back 52

Nitrogen
Oxygen
Water vapor
Carbon dioxide
Oxygen
Carbon dioxide

Front 53

Through a process called photosynthesis, plants convert _______ and water into glucose, which they use for food. A byproduct of this process is ______ is______. In addition to allowing plants to manufacture their own food, ____ helps regulate the temperature of the earth. Through a process referred to as the ____, this gas traps heat that radiates from the earth. Without such gases, the average temperature of the earth would be far too _____ to support life.

Back 53

Carbon dioxide
Oxygen
Carbon dioxide
Greenhouse effect
Low

Front 54

If the greenhouse effect ran out of control, we would have ____, a situation in which the average temperature of the earth increased over time. Although this would be bad, the greenhouse effect is ___, as it makes life on earth possible. Since carbon dioxide is a gas that participates in the greenhouse effect, the fact that the concentration of carbon dioxide in the atmosphere is __makes some people fear that____ may already be happening.

Back 54

Global warming
Good
Rising
Global warming

Front 55

The average temperature of the earth has changed ____ in the past 100 years. There was a small ____ in the average global temperature from the late 1800’s to the early 1900’s, but that was before carbon dioxide levels in the atmosphere ___ significantly. Thus, there is ____evidence that increasing carbon dioxide concentration causes_____. In addition, the earth was significantly ____between the ninth and fourteenth centuries than it is today.
Little

Back 55

Increase
Increased
Little
Global warming
Warmer

Front 56

Ultraviolet light is ___ to living organisms, because it has enough energy to __ living tissue.

Back 56

Harmful
Kill

Front 57

Although the sun produces a significant amount of ultraviolet light, most of it is blocked by ___ in the ____layer. This gas is ___, but the ____layer is high above sea level, where no one is breathing.

Back 57

Ozone
Ozone
Poisonous
Ozone

Front 58

Even though most ultraviolet light from the sun is blocked, some gets through, and if your skin is exposed to too much of it, you can get a ___.

Back 58

Sunburn

Front 59

When we report concentration in parts per million, we are reporting the number of molecules (or atoms ) of a substance in a mixture for every 1____ molecules (or atoms) in that mixture. The concentration of many pollutants is often expressed in parts per million, as their concentrations are very ___. Despite what many people think, the concentrations of pollutants in earth’s atmosphere have been ___ for some time. Thus, the air we are breathing today is ___than it was 30 years ago.

Back 59

Million
Low
Decreasing
Cleaner

Front 60

Sulfur oxides are put in the atmosphere when sulphur___. Sulfur is a _____ in all ____we burn. The sulphur content of coal can be ____in a process called “cleaning” Many industries have devices in their ___ that help clean the sulphur oxides out of the mixture of gases that result from burning fuel. These devices are commonly called _____. Although human activity puts sulphur oxides in the atmosphere, there are natural sources as well, one of the most important being _____.

Back 60

Burns
Contaminent
Fuels
Reduced
Smokestacks
Scrubbers
Volcanoes

Front 61

Nitrogen oxides are formed when _____burns. This happens at very high _____, so engines and power plants are major human-made sources of nitrogen oxides. There are, however, many natural sources of nitrogen oxides as well, such as ____, _____, and _____.
Nitrogen

Back 61

Temperatures
Volcanoes
Lightning
Biological

Front 62

While ozone in the ozone layer protects living organisms, ozone is a _____. Thus, _______-level ozone is a pollutant, because people breathe it.

Back 62

Poison
Ground

Front 63

________ is a toxic byproduct of incomplete combustion. Unlike carbon dioxide, gas can be ____, even at concentrations as low as a few hundred parts per million. Automobiles used to be a major source of this gas, but the introduction of ____ significantly reduced the amount produced in automobiles by converting the gas into____.

Back 63

Carbon monoxide
Deadly
Catalytic converters
Carbon dioxide

Front 64

The U.S. government began issuing standards called ___, which regulate the average number of miles an automobile can travel on a single gallon of gasoline. Although these standards do ___automobile-related pollution, they also _____ the number of traffic facilities.

Back 64

CAFÉ standards
Reduce
Increase

Front 65

When one compares the positive result of an action to the negative result and decides whether or not the positive result was worth the accompanying negative result, we say that the person has done a ______.

Back 65

Cost/benefit analysis

Front 66

Any reasonable discussion of air pollution ___ must include such an analysis in order to ensure that the reduced pollution is worth whatever accompanying costs exist.

Back 66

Regulations