Given what you now know about the ideal gas law, consider an investigation to determine the identity of an unknown pure gas.

a. What would be an appropriate beginning question for this investigation?

b. What variables would you need to measure?

c. What variables, if any, would you need to control?

d. How could you measure each of the variables?

Consider Investigating Matter B.8, Phase Changes.

a. What would be an appropriate beginning question for this investigation?

b. What are the variables of interest?

Considering the identity of the criteria pollutants and the sources of air pollutants in the United States where should air-qualit y monitoring devices be located? Explain .

What pattern would you expec t to find among pH readings taken of preci pit ation in the immedia te vicinity of an acid -rain producing smokestac k and at regular intervals downwind and upwind from the site? Sketch a graph of what you would expec t to find.

Collision theor y states that molecules can break bonds and form new substances when they collide with sufficient energy and suitable orientation . What types of evidence could support each of the following aspects of collision theory?

a. Formation of new substances.

b. Requirement for sufficient energy.

c. Requirement for suitable orientation

Heat is often described as "lost energy." For instance, automobile engines release about $75 \%$ of the energy from gasoline combustion as heat. Explain this idea of energy loss in terms of your understanding of heat.

Why is the presence of ozone regar ded as a problem at ground leve l, whil e the absence of ozone is regarded as a prob lem in the stratosphere?

If air at $25^{\circ} \mathrm{C}$ has a density of $1.28 \mathrm{~g} / \mathrm{L}$ and your classroom has a volume of $2.0 \times 10^5 \mathrm{~L}$,

a. what mass of air is contained in your classroom?

b. assume that the room temperature is increased. How would that affect the total mass of air contained in the room,

i. if the room were tightly sealed?

ii. if the room were not sealed?

Consider the data you graphed in Developing Skills C.2.

a. List two scientific claims you could make based on the data or the graph.

b. For each claim, cite evidence for making that claim.

What would happen to the pressure exerted by a gas sample if both the temperature of the gas and the volume occupied by the gas were doubled , while holding the amount of gas constant?

U.S. weather reports generally express air pressure in units of inches of mercury . During a severe storm, the barometric pressure can drop as low as 27.2 inches of mercury. Convert this air-pressure value to:

a. millimeters of mercury (mmHg). (Hint: l inch = 25.4 mm)
b. atmospheres (atm).
c. kilopascals (kPa).

a. Has the atmosphere's composition changed significantly throughout human history?

b. What evidence can you cite to support your claim?

Write and balance the equation for formation of $\mathrm{SO}_3$ from $\mathrm{SO}_2$ and oxygen.

Use your own words to describe each of the following : How the relationships described in your answers.