Scientists are interested in investigating how limestone can be used to remediate the effects of acid rain. They collect water from a lake that has recently been exposed to acid rain. They divide the water into 10 different tanks and add different amounts of limestone to nine of the tanks. No limestone is added to one of the tanks. The pH of the water in the tanks is measured before the limestone is added and once every hour for 24 hours. (f) Identify the independent variable in this investigation. (g) Identify the dependent variable in this investigation. (h) Identify the control group in this investigation. (i) Describe one additional variable that has not been mentioned that could affect the results of the investigation. (G) Describe a modification that could be made to the investigation that would affect the results.

A team of investigators is out on a boat on a lake on a marvelous,sunny summer day, and they are taking water samples fromvarious depths in the lake so as to construct a plot of dissolvedO2 concentration versus depth, similar to the plot in Figure 1.16.When the investigators bring up a water sample from a depthof 20 m, why is it imperative that they measure its dissolved O2concentration immediately, rather than letting it sit on the deckfor 5 minutes? (Hint: Look at Figure 22.2A.

define : a. isotonic slution b. hypertonic solution c. hypotonic solution

For the questions below be sure to show your work as well as the answer to the question. In this week's lab you made 100ml of 10x PBS by dissolving 8 g NaCl, 1.2g Na₂HPO4 and 0.2 g KH₂PO4 in water. You then adjusted the pH to 7.0. A) How many mg of KH₂PO4 did you weigh out? B) How many liters of 10x PBS did you make? C) What is the final concentration of NaCl in your solution? (The molecular weight of NaCl is 58.44 g/mol) D) What is the final concentration of Na₂HPO4 in your solution? (The molecular weight of Na₂HPO4 is 141.96 g/mol) E) What is the final concentration of KH₂PO4 in your solution? (The molecular weight of KH₂PO4 is 136.1 g/mol) F) What is the hydrogen ion concentration of your solution (pH=7.0)? G) If the initial pH of your solution was 6.29 would you need to add an acid or a base to adjust the pH of a solution to pH 7.0? 10x PBS is a concentrated stock solution that is used to make more dilute solutions of PBS. Starting with your 10xPBS stock solution, how would you…

Examples of nitrogenous wastes are:A fatty acids and glycerolB water and carbon dioxideC urea and uric acid