How Does Ion Concentration Interact with Physical Environments and Living Systems?

Answer each question by clicking the correct blue button. Only the first answer selected is graded.

1. Why should we use caution when operating electrical appliances around water?
A. The electricity causes the water to become nonpolar.
B. Tap water has enough dissolved ions to complete a circuit between the electrical appliance and your body.
C. Properties of water will slow down the electrical current.
D. N/A.

2.  How does MgCl2 break up into ions when dissolved in water?
A. MgCl2(aq) ____ Mg+(aq) + 2Cl- (aq)
B. MgCl2 (aq) _________ Mg+(aq) + Cl- (aq)
C.MgCl2 (aq)__________ Mg+2(aq) + 2Cl- (aq)
D. N/A.

3.  Mary's first gardening experience was a failure. The few plants that did sprout were not healthy. She took a soil sample to a lab and found the pH of her soil was too alkaline. A good gardening soil needs to have a pH around 5.5 to 7.5. She could add lime to the soil to raise the pH or sulfur to lower the pH. Should she use the lime or sulfur?
A. Mary should use sulfur.
B. Mary should use lime.
C. Mary should use a combination of both.
D. N/A.

4.  John’s dog was sprayed by a skunk and then came through the doggie door to the living room. John then blocked the dog in the corner. “Whew, I’m glad I got to him before he roamed all over the house! I’m tired now so I’ll bathe him tomorrow when I get home from school.” When John boarded the bus the next morning, everyone in unison screamed, “SKUNK!” Why did John smell like skunk even though he never touched his dog?
A. Maybe John got sprayed by the skunk and didn’t realize it.
B. The sulfur compound in skunk spray diffused through the rest of the house.
C. His buddies on the bus were just having some fun.
D. N/A.

5.  Unpolluted rain has a pH of 5.6 which is naturally acidic. This acidity results from the dissolution of carbon dioxide in the water producing carbonic acid:
CO2 (g) + H2O (l) _________ H2CO3 (aq). The eastern United States usually has a lower pH of rain than in the western states. Why?

A. The western states don’t have as many trees in the Rocky Mountains producing CO2 .
B. The eastern states have more trees in the Blue Ridge Mountain Range producing CO2.
C. The industry of eastern states has more nitrogen and sulfur oxides in the air and when mixed with rain produces acids.
D. N/A.

6. What are the relative concentrations of H+ (aq) and OH- (aq) in a neutral solution?
A. Concentration of H+ = concentration of OH-
B. Concentration of H+ > concentration of OH-
C. Concentration of OH- > concentration of H+
D. N/A.

7.  Why does a solution of CaCl2 conduct a slightly stronger electrical current than an equal concentration of NaCl solution?
A. NaCl does not ionize in solution.
B. NaCl and water form a nonpolar compound.
C. CaCl2 ionizes into 3 ions, Ca++ and 2Cl- while NaCl ionizes into only 2 ions.
D. N/A.

8.  Mary ate 5 bags of sweet tarts. Later, she noticed a sore spot on her tongue. What can she do to find relief?
A. Mary must accept that over indulgence leads to misery and do nothing.
B. Mary can apply baking soda to the sore spot to neutralize the effects of acidity from the candy.
C. Mary can buy 6 bags of chocolate candy and melt her problems away.
D. N/A.


Grade exam.