MGH CHEM CH. 2 HW

O3

ozone

The concentration of water vapor in air _______.

varies widely according to location

1 ppm is _____ times smaller than 1%.

10,000

pure substance

Form of matter with a definite composition

Which of the following options correctly describe the troposphere? Select all that apply.

- An inversion layer in the troposphere occurs when cooler air is trapped below warm air. - 75% of our air is found within the troposphere. - the troposphere is the region of the atmosphere in which humans live.

which are products of respiration?

- CO2 -H2O

Which of the following options correctly describe gases? (Select all that apply.)

- Gas molecules are in constant random motion. - Gas molecules are extremely small. - Gases are mostly empty space.

Which of the following statements correctly describe different forms of matter? Select all that apply.

- Mixtures can consist of any four phases of matter. - Both mixtures and pure substances are forms of matter.

Which of the following options correctly describe N2 (nitrogen gas)? Select all that apply.

- Nitrogen is the most abundant substance in air. - Nitrogen is colorless and odorless.

Which of the following options correctly describe the characteristics and role of oxygen? Select all that apply.

- O2 is a necessary reactant in burning and rusting. - Oxygen atoms are the most abundant atoms by mass in the human body. - O2 is absorbed into our blood via the lungs.

Which of the following are examples of mixtures? Select all that apply.

- tap water -soil

Place the gases that make up air in order of decreasing percent composition, starting with the most abundant gas at the top of the list.

1. Nitrogen 2. Oxygen 3. Argon

Place the layers of Earth's atmosphere in the correct order, starting with the layer that is closest to Earth at the topof the list.

1. troposphere 2. stratosphere 3. mesosphere 4. thermosphere 5. exosphere

If air is composed of 78% nitrogen this means that by volume air contains 78 parts nitrogen for every ______ parts of air.

100

di

2

penta

5

hexa

6

hepta

7

The composition of air by volume is about 21% oxygen. For every 100 molecules, how many molecules are not oxygen?

79

mixture

Physical combination of two or more species

NH3

ammonia

Which biome is likely to have the lowest concentration of water vapor in the air?

desert

Gas molecules are in constant random motion and are extremely _____ under normal atmospheric conditions. If the gas molecules in a sample of air were condensed, their actual volume would be very _____.

far apart; small

CH4

methane

For low concentrations, it is more convenient to use units of parts per ______ (ppm), instead of percent. This unit is of a concentration 10,000 times smaller than 1%.

million

Which of the following is the correct name for the compound NO2?

nitrogen dioxide

When naming a compound composed of two nonmetals, the number of atoms of each element is indicated by a Greek numerical

prefix

In the process of ______, the foods that we eat are metabolized to produce carbon dioxide, water, and energy.

respiration

Which two gases are the main components of a typical sample of air?

- oxygen - nitrogen

Equal volumes of gases contain equal numbers of atoms or molecules, as long as the samples are at the same _____ and _____.

- temperature - pressure

mono

1

The correct formula for the compound dichlorine pentoxide is Cl ___O__

2;5

What is is the correct chemical formula for sulfur tetrafluoride?

SF4

Which of the following options correctly describe how to name a compound containing two nonmetals? Select all that apply.

- A Greek numerical prefix is always used when more than one atom is present to indicate the number of atoms of each element in the compound. - The name of the first element remains unchanged, except for the addition of a prefix where appropriate. - The second element is named with its root and the suffix -ide.

H2O

water

Which of the following options correctly describe the characteristics and behavior of argon, which is a component of air? Select all that apply.

-Argon makes up less than 1% of air. - Argon is a typical component of air.

Which of the following options correctly describe air pollutants? Select all that apply.

-Some air pollutants are hazardous at levels well below 1 ppm. - Particulate matter is an example of an air pollutant.