* not completed

. The value of Henry's Law constant for oxygen can be expressed as 1.3 x 10^-3 mol L^-1 atm^-1. The SI unit for the constant is mol m^-3 Pa^-1. What is the value using this SI unit?

1.3x10^-8 correct incorrect

1.3x10^-5 correct incorrect

0.77x10^-8 correct incorrect

1.3x10¹¹ correct incorrect

0.77x10⁸ correct incorrect

* not completed

. At 5^oC, the equilibrium solubility of oxygen in water is 12.4 mg L^-1. What is the value of the Henry's Law constant at this temperature? (Please select all that apply)

3.8x10^-9 mol L^-1 Pa^-1 correct incorrect

3.9x10^-4 mol L^-1 atm^-1 correct incorrect

3.8x10^-6 mol m^-3 Pa^-1 correct incorrect

1.2x10^-7 mol L^-1 Pa^-1 correct incorrect

7.6x10^-9 mol L^-1 Pa^-1 correct incorrect

* not completed

. The Henry's Law constant for many gases when they dissolve in water is greater at low temperatures than at high temperatures. This implies that: Please select all that apply.

Dissolution is an exothermic process correct incorrect

Dissolution is an endothermic process correct incorrect

Entropy changes increase solubility at low temperatures correct incorrect

Water behaves anomalously compared to other liquids correct incorrect

The Henry's Law constants are not valid when water is the solvent correct incorrect

* not completed

. A small isolated lake with average depth of 12 m and having an alkalinity of 35 μmol L^-1 is subjected to 1200 mm of yearly rainfall with average pH 4.2. Assuming no removal of the added H₃O⁺, how many years will it take to change the lake status from 'transitional' to 'acidic'?

  0.46 correct incorrect

  0.18 correct incorrect

  2.9 correct incorrect

  5.5 correct incorrect

34 correct incorrect

* not completed

. In recent history the average ocean pH has been 8.2, but within another 30 years, the average is expected to be 8.0. What would be the percentage increase in hydrogen ion?

2.0 correct incorrect

58 correct incorrect

-19 correct incorrect

-2.0 correct incorrect

72 correct incorrect

* not completed

. The following equation describes the basic chemical equilibria of CO₂ in the ocean (at pH 8.2)
CO₂(g) ←→ CO₂(aq) + H₂O ←→ H₂CO₃ ←→ H⁺ + HCO₃⁻ ←→ 2H⁺ + CO₃^2-
(Please select all that apply)

In the oceans, most of the dissolved carbon dioxide is in the HCO₃^- form correct incorrect

Acidification causes an increase in CO₃^2- concentrations in the ocean correct incorrect

Photosynthetic rates are also suppressed by increased CO₂ in the seawater correct incorrect

H⁺ will increase with increasing CO₃^2- correct incorrect

H⁺ will increase with increasing HCO₃^- correct incorrect

* not completed

. Which of the following statements about ocean acidification is/are true? (Please select all that apply)

A decrease in pH of seawater from 8.2 to 8.1 means an approximate 10% increase in acidity correct incorrect

For carbon dioxide, the K_a values are smaller in seawater than in fresh water correct incorrect

For a calcium carbonate, a value of Q_sp/K_sp that is greater than 1 means that there is a tendency for dissolution to occur correct incorrect

Carbon dioxide is the only acid causing an increase in ocean acidity correct incorrect

CO₃^2- is the principal species of the carbonate system in seawater correct incorrect

* not completed

. Which of the following statements about alkalinity is/are true? (Please select all that apply)

A lake with a pH of 9.5 always has a high alkalinity correct incorrect

Natural organic matter (NOM) is included in the measurement of alkalinity correct incorrect

The molar concentration of carbonate is multiplied by 2 in the determination of alkalinity correct incorrect

Acid neutralizing capacity (ANC) is the same as alkalinity, just using a more scientific name correct incorrect

Alkalinity is a capacity factor, allowing you to know the ability of a water sample to sustain reactions with added acids or bases correct incorrect

* not completed

. Which of the following statements about lake acid/base properties is/are true? (Please select all that apply)

A well-buffered lake has a high acid neutralizing capacity and a pH around 6.5 correct incorrect

A lake that has just fallen into the transitional range will turn acidic within a few months correct incorrect

A lake with a pH of 6.5 will still have some alkalinity in it correct incorrect

A lake with an alkalinity of 22 mg CaCO₃^2- L^-1 is considered to be a lake that is sensitive to acid input correct incorrect

The pH of a lake does not matter as long as the alkalinity is high enough correct incorrect

* not completed

. Which of the following statements about alkalinity is/are true? (Please select all that apply)

Alkalinity can be expressed using units of mg L^-1 CaCO₃ correct incorrect

Alkalinity is a measure of the ability of a water body to neutralize acidity correct incorrect

Alkalinity of 100 mg L^-1 for a lake is considered to  be a high value correct incorrect

Alkalinity can be expressed using units of μmol L^-1 of proton acceptors correct incorrect

Alkalinity is analogous to the inverse of pH correct incorrect