Module 2

A(n) _____ is a substance that increases the rate of a reaction without being consumed. This type of substance is often used up but regenerated during the reaction.

Catalyst

A(n) _____ pollutant is produced from chemical reactions involving one or more other pollutants.

Secondary

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

Match each symbol correctly to the state of matter it represents. Gas, solid or liquid (s) (g) (I)

(s) -> Solid (g) -> Gas (l) -> Liquid

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

- Atoms are extremely small. - Compounds contain two or more different types of atoms. - An atom is the smallest unit of an element that can exist as a stable, independent entity.

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

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

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 actions are permitted in balancing a chemical equation?

- Multiplying all coefficients by a common factor - Adding coefficients to formulas of reactants and products

Ozone decomposes into oxygen and atomic oxygen. Which of the following statements correctly describe the balanced equation for this reaction? Select all that apply.

- O2 is a product of the reaction. - There are 3 toms of oxygen on the left side of the reaction and 3 atoms of oxygen on the product side of the equation.

Which of the following statements correctly describe the information gained from a balanced chemical equation? Select all that apply

- Often the physical states of reactants and products. - Identities of substances involved. - Relative quantities of substances involved

Which of the following options describe the correct format used when writing the chemical formula of a substance? Select all that apply.

- The number of atoms of a particular element is indicated by a subscript. - A chemical formula is a symbolic way to represent the composition of a substance.

The concentration of hydrogen in air is 0.000055%. What is this value in ppm?

0.55 ppm

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

Rank the pollutants from the most to the least toxic, based on the values given in the accompanying table. Be careful; note that these numbers are the concentration levels deemed unsafe. Start with the most toxic pollutant at the top of the list.

1. PM (2.5) 2. O(3) 3. CO

1 ppm is _____ times smaller than 1%.

10,000

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

100

Which of the following statements correctly defines a molecule?

A molecule is independent structure consisting of two or more atoms chemically bonded together.

Match each of the following species with the correct classification (Mixture or Pure Substance) - Air - Oxygen (O2)

Air -> Mixture Oxygen (O2) -> Pure Substance

Balance the unbalanced equation given and match each substance to the correct coefficient as indicated. Al(s) + O2(g) -> Al2O3(s)

Al -> 4 O2 -> 3 Al2O3 -> 2

Which of the following are toxic gaseous pollutants that way be found in air? Select all that apply.

CO (Carbon Monoxide) O3 (Ozone) SO2(Sulfur dioxide)

The rapid reaction of fuel with oxygen to release energy

Combustion

Consists of two or more elements, chemically bound

Compound

A chemical equation that is properly balanced obeys the law of _____.

Conservation of mass

Contains only one type of atom

Element

C2H6

Ethane

A chemical equation is a statement using chemical _____ that expresses both the identities and the relative _____ of the reactants and products involved in a chemical or physical change.

Formulas, amounts

If a compound is composed of nitrogen and hydrogen atoms in a respective one-to-three ratio, what is the correct chemical formula for this compound?

NH3

Largest component of the air

Nitrogen

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

Nitrogen Dioxide

A chemical equation must be balanced. This means that the same _____ and _____ of atoms must appear on both side of the equation.

Number; Type

Which of the following are elements? Select all that apply.

O(2) Na Cu

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

Prefix

Give the correct chemical formula for sulfur tetafluoride. Do not use any special formatting; simply enter the element symbols and the numbers associated with each one in the correct order.

SF4

Managing human consumption of natural resources so that these resources are not exhausted is called _____.

Sustainability

The intrinsic health hazard of a substance

Toxicity

The risks presented by air pollutants are a function of what thing(s)? Select all that are correct

Toxicity & Exposure

The common name for the compound H2O is _____, while the compound NH3 is commonly known as _____.

Water, ammonia

How would you express .002 molecules of CO2 per hundred molecules of air as a concentration?

20 parts per million

Combustion is an example of a type of chemical _____, where reactants are transformed into products.

Reaction

Lowest region of the atmosphere

Troposphere

Rank the three pollutants listed in the table below in order of decreasing toxicity, based on the U.S. National Ambient Air Quality Standard for a 1-hour exposure period. Start with the most toxic pollutant at the top of the list. CO - 35 NO2 - 0.100 SO2 - 0.075

1. CO2 2. NO2 3. CO

What is the correct name for the following molecular compound: CCl4?

Carbon Tetrachloride

The typical amount of water vapor at the surface of the Earth is 10,000 - 40,000 ppm. What is this value as a percent?

1 - 4%

Balance the following chemical equation: N2 + O2 ⟶ NO2 , by giving the correct coefficients for the N2, O2 and NO2 respectively.

1,2,2

The Air Quality Index (AQI) is scaled from ___ - ___ .

1-500