Author: Anonymous

  At the start of this experiment each of these tubes contained an acidic solution and a buffer. An equal amount of sodium hydroxide (NaOH) was then added to each solution. The results are shown here. Which tube (A, B or C) contained the best buffer? Explain your answer.

A civil engineer wanted the water to drain away from his completed construction project, so the design of the project needed to include the creation of a slope/angle away from the project.  The engineer was also concerned that with a slope significant soil erosion that might occur.  Soil erosion is the washing away of soil caused by water flow over its surface.   He designed an experiment in which he set up 5 trays with equal amounts of the same type of dry soil at different slopes.  He poured an equal amount of water over each tray, simulating rainfall that would be normal for the area.  He then collected, dried and weighed the amount of soil that ran off of each tray.  He repeated the experiment several times. The following is a data table showing the average of the results of his experiment. Tray Slope/Angle Soil Runoff (g) 1 0o 0 g 2 10o 8 g 3 20o 12 g 4 30o 50 g 5 40o 65 g   Write a hypothesis for this experiment.  

Convert the following:        643.5 cm = [number1] m      905.2 ml = [number2] liters      0.564 kg = [number3] g      8.72 m = [number4] mm      56789 m = [number5] km      3.499 g = [number6] mg    

Based on the data collected in the above experiment, what grade of incline would you recommend? Why?

A sample of urease enzyme was heated to 100oC and then cooled. This sample of enzyme was then used to catalyze a reaction at 40o   This reaction did not produce any carbon dioxide product.  Why?  Explain what has happened to give this result.

Which sample(s) contain simple sugars? TEST SAMPLE A SAMPLE B SAMPLE C SAMPLE D Biuret + – – – Potassium iodide – – + – Benedict’s – – + + Translucence + + – –

Which sample is most likely to be fruit juice? TEST SAMPLE A SAMPLE B SAMPLE C SAMPLE D Biuret + – – – Potassium iodide – – + – Benedict’s – – + + Translucence + + – –

Nitrogen in animal wastes is often in the form of urea.  Plants cannot absorb and use the nitrogen as a nutrient in this form; it must be broken down by a series of reactions.   In the presence of water, the enzyme urease converts urea into ammonia and carbon dioxide.                                                       urease (NH2)2       +      H2O      ——–>           2NH3           +      CO2   urea               water                             ammonia           carbon dioxide   What are the substrates/reactants in this reaction?

At the beginning of this experiment a bag containing a yellow solution (water + yellow solute) was placed in a beaker containing a blue solution (water + blue solute). The results of the experiment are displayed here. Which color of solute was able to cross the membrane? [solute] What is the specific name of the process by which the solute crossed the membrane? [process]

Identify the cell structure labeled A. [a] Identify the cell structure labeled B. [b] Identify the cell structure labeled C. [c]