Exploring Chemistry in Our World


Additional Material Features

Student Workbook

Teacher's Manual

Unit Review

Additional Material

PowerPoint Presentation

  • Features supplementary labs and exercises
  • Includes list of recommended websites for each unit
  • Contains Chemistry Insights and "A Closer Look" material
  • Correlated to exercises found in Labs & Worksheets
  • Included on the Teacher Component disc as Word files

Below is an excerpt from Unit H of Additional Material

Unit H - Behavior of Gases

A Closer Look: How to make a graph using a spreadsheet program

Plot Graph:
  1. Enter x-axis data into column A (e.g., time).
  2. Enter y-axis data into column B (e.g., space, velocity, etc.).
  3. Using cursor, highlight data. Click on Chart Wizard.
  4. Select x-y scatter. (Use the one showing points and a smooth curve.) Click NEXT.
  5. Click Series to make sure x-axis data is on x axis and y-axis data is on y axis. (If not, correct before going on.) Then click NEXT.
  6. Put in Title, Labels; remove Legend (adding gridlines is optional), and click NEXT.
  7. Put in as a New Sheet. Click FINISH.

Add Trendline (shows the best straight line through the data):
  1. On Toolbar, click Chart. Then click Add Trendline.
  2. We will use a linear trendline.
  3. Go to Options; in Forecast section, set Backward amount to a value equal to your lowest x-value reading; finally, click Display Equation. Then click OK. (You graph should now show connected data points, a trendline through the data points, and an equation of the line.)
  4. Right-click on Trendline on the graph itself. Cllick on Format Trendline and go to Patterns. Change Style to a dotted line and Weight to a lighter amount. Then click OK. Your graph will appear.
  5. Now Print the graph.

Insights: Chemistry and the Body—Diving and Henry’s Law
Have you ever noticed gas bubbles forming inside a glass of soda pop? These bubbles only appear because the liquid is no longer under enough pressure to hold the gas in solution. The decreased pressure reduces the amount of gas that can be dissolved. This dependence of gas solubility on pressure is called Henry’s Law.

The Bends:
Both pilots and divers can experience a condition known as the “bends.” The name for this condition probably resulted from the fact that the diver is doubled over with pain. This condition is really a sickness caused by rapid decompression.
     The bends results from the formation of bubbles of nitrogen gas in the blood and body fluids. Under high-pressure conditions, significant amounts of nitrogen from the air we breathe are dissolved in body fluids. A sudden reduction in atmospheric pressure causes the solubility of nitrogen gas to decrease. The excess nitrogen gas forms bubbles. Wherever the nitrogen bubbles form, normal circulation to that part of the body is cut off.
     If a bubble cuts off circulation in the brain, dizziness, blindness, paralysis, convulsions and unconsciousness may result. In the joints, great pain is experienced. In the lungs, choking and asphyxia result. If a bubble forms in an artery supplying blood to a vital organ, such as the heart, the victim can die of a “heart attack.”
     If a diver returns too rapidly to the surface of the ocean from a deep dive, he or she may get the bends and it may, in some cases, be fatal. A similar condition can result from a pilot climbing to high altitudes too rapidly. Having the diver breathe a special mixture of gases can reduce the danger of getting the bends. One such mixture is helium and oxygen. Helium is less soluble in the blood and in any body fluids than nitrogen. Therefore, bubbles of helium are less likely to form as the diver is brought to the surface. Another way to prevent the bends is to decompress slowly. The diver stays a period of time at each higher level. His lungs remove the nitrogen dissolved in his body fluids during normal respiration without forming bubbles.
     Another related condition is called nitrogen narcosis or “rapture of the deep.” The body experiences a drug-like stupor at higher concentrations of nitrogen. Diving only for short periods of time or using a helium-oxygen breathing mixture can eliminate this problem.

Ascending from the Depths:
One way to remove air from body cavities is for it to pass into the veins. If bubbles form from decreased pressure, they circulate through the blood until they plug small arteries and capillaries. An embolism is the name given to such a result and it can lead to unconsciousness and death. Air can also pass into the space between the lungs and the heart known as mediastinum. This produces a type of emphysema that causes severe chest pain, breathing problems and faintness. If air gets between the lungs and the rib cage, the lungs collapse. This is called pneumothorax.
     Divers must learn never to hold their breath. Scuba divers are taught to breathe normally and to exhale during ascents.

A Closer Look: How Heavy Is Your Car?

To estimate the weight of your car.

Predict the weight of your car.

  • car
  • 4 sheets of paper
  • tire gauge

Ensure the car is parked with the emergency brake engaged.

  1. Determine the area (in2) of each tire in contact with the ground. (Do this by slipping the paper under the tires in all four directions as far as they will go. Then tape the sheets together. Remove the sheets and measure the area covered by the tire.
  2. Measure the pressure of the tire (lbs/in2). (Use the tire pressure gauge.)
  3. Multiply the tire pressure by the area of the tire to obtain the weight load of the tire.
  4. Repeat for the other three tires.
  5. Calculate the total weight of the car.
  6. Compare your estimate with the owner’s manual.
  7. If the car’s tires were hot from being recently driven, how might this affect your results? Would the area measured be the same for each tire? Explain. Would the air pressure be the same? Explain.

Data and Results:
Record your data and results in the appropriate table. Calculate the percent error.

Explain what you learned by doing this experiment. What are some possible sources of error in this experiment?

Suggested Websites for Unit H: