A student decides to set up an experiment that night before performing the experiment. A 0.40 g sample of sodium hydroxide in a 250 mL beaker that has a mass of 112.58 g. The beaker is allowed to stand open (exposed to air) for 24 hr. At that time, the student observes that the beaker contains a dry, white residue and the total mass of the beaker and the residue is 113.09 g. He proposes that a reaction must have occurred between the sodium hydroxide and the carbon dioxide in the air. The possible reactions are:

sodium hydroxide(s) + carbon dioxide( g) -> sodium carbonate (s)

sodium hyroxide (s) + carbon dioxide (g) -> sodium carbonate (S) + water (g)

sodium hydroxide (s) -> sodium oxide (s) + water (g)

Write the balanced chemical equations for the above reactions.

Determine the amount of solid product expected in each reaction.

Based on these calculations, which of the above reactions would you predict is correct? Show all the work including chemical equations and explain your choice. Thank you.

Experiment 8 – Air and the Ideal Gas Laws

This experiment will follow the procedure outlined in Experiment 8 in the lab manual. You may find it useful to review the Gas Laws in the lecture text before lab along with the lab manual Introduction, Theory and Procedure.

1. Define an ideal gas and how this definition is related to the Kinetic Molecular Theory of Gasses. Provide at least one citation for this question.

2. Define a real gas and how this definition is related to the Kinetic Molecular Theory of Gasses. Provide at least one citation for this question.

3. Discuss under what set of conditions a real gas is most likely to deviate from ideal behavior and why.

4. Using Equations 8.4 and 8.6, calculate the volume of 0.523 moles of water vapor at 300 K and 0.986 atm – you must show all work, including necessary unit conversions. Compare the value obtained from both equations and explain how your results compare to the theory discussed in the lab manual.

experiment: colligative properties

Water cannot be used as the solvent for this experiment. For what types of molecular substances - give specific examples - could water be used as a suitable solvent to determine a molecular weight?

Can water be used to determine the formula weights of all ionic compounds? What are the limitations, if any?

Why does the slope of the mixed solution continue to decrease rather than reaching a plateau like that observed for the pure liquid? Hint: When the solution freezes the solid is pure solvent.

Experiment 3: Charging by Contact and Induction
In this experiment, you will charge pith balls by contact and induction.

Materials
Electrostatics Kit
Masking Tape
Monofilament Line
Paperclip
Wooden Block with Slit     
*Metal Object (ex. Doorknob)

*You Must Provide  
  

Procedure
1.   Tear one small piece of masking tape from the roll (approximately 5 cm).
2.   Create a small, closed loop with the tape, leaving the sticky side on the outside of the loop.
3.   Secure the looped tape to one of a side of the wooden block adjacent to the side with the slit.
4.   Press the taped side of the wooden block onto a smooth wall (or the flat side of a counter or table top) with the slit pointing perpendicular to the wall and parallel to the floor.
5.   Unwrap the outer layer of a paperclip.
6.   Use the exposed end of the paperclip to poke a hole through the centers of two pith balls.
7.   Thread one end of the monofilament line through one of the pith balls. Tie a knot on the end that you threaded through to keep the pith ball on the thread.
Note: If the paperclip created a larger hole, three to five knots may need to be tied to secure the ball on the thread.
8.   Repeat Step 7 on the other end of the monofilament line with the other pith ball.
9.   Once the pith balls are secured on each end of the line, place the line in the slit of the wooden block. The pith balls should rest at the same height.
10.   Remove any charge from the acetate strip (wide and clear) by grabbing it with your hand or rubbing it on a metal object like a door knob. This is called grounding.
11.   Test for interactions between the acetate strip and both pith balls. Record observations of any interaction.
12.   Charge the acetate strip by rubbing it with the cotton cloth.
13.   Slowly bring the plastic strip close enough to the right pith ball so that it moves, but does not touch the plastic strip. Once movement of the pith ball is observed move the plastic strip away. Record your observations (e.g., how far away were the two objects, how fast did the pith ball move, in what direction did the pith ball move, etc.).
14.   Slowly bring the plastic strip close enough to the left pith ball so that it moves, but does not touch the plastic strip. Once movement of the pith ball is observed move the plastic strip away. Record your observations.
15.   Hold the monofilament line above the right pith ball and bring the ball into contact with the plastic strip.
16.   Let the pith ball hang again and bring the plastic rod close to, but without touching the right pith ball. What kind of interaction is observed? Record your observations in Post-Lab Question 3.
17.   Hold the line above the right pith ball and bring it close to the left pith ball. Observe what happens. Let the balls come into contact. How does that change the interaction?
18.   Grab the pith balls to ground them and take away any charge they may have.
19.   Charge the plastic rod again with the cotton.
20.   Hold the line above the right pith ball with your pointer and middle finger. Bring the right pith ball close to the plastic rod, but do not let them touch. This time touch the left side of the ball (the one opposite of the rod) with your thumb. Let the ball hang again. Bring the right pith ball close to the left pith ball. Observe what happens.
Observations

After step 10-14 we can see a movement off the balls in the direction of the plastic strip (after rubbing it with a cotton cloth). The balls moves as close as it can to the plastic strip (like 2-3 cm)
When we put the plastic strip close enough to the left pith ball it moves to the left

Step 16- they were attracted to each other (the ball and the plastic)
Step 17- the balls a little bit attracted to each other but not too much

Post-Lab Questions

1.   Explain why the pith balls were attracted to the charged plastic strip.

2.   State two observations that show the right pith ball was charged after it came into contact with the plastic rod.

3.   What did you observe as you performed Step 16? Use your results to explain what happened.

4.   Draw a diagram to show how Step 13 charged the right pith ball.

5.   What is the charge of each pith ball if they are attracted to each other? Explain your reasoning.

Experiment 2: Static Materials
In this experiment, you will investigate the phenomenon of static electricity of various materials.

Materials
Electrostatics Kit Materials
*Paper (Any Kind)
*Flat Work Surface     

  
Procedure
1.   Tear the paper into small pieces (approximately the size of a hole-punch) and scatter them in a small area on a table or flat surface.
2.   Choose one plastic strip (acetate [light blue and transparent], vinyl [no color and transparent], or polyethylene [white and translucent]) and one fabric (wool or cotton cloth) from the electrostatics kit.
3.   Quickly rub the fabric up and down the length of the plastic strip for approximately 20 seconds.
4.   Bring the plastic strip near the small, torn pieces of paper.
5.   Record observations about the amount picked up and behavior of the paper in Table 2.
6.   Repeat Steps 2 – 5 for five additional fabric and plastic combinations.

Table 2: Static Electricity Properties of Various Materials

  
    Post-Lab Questions

1.   What happens when you bring the charged plastic strip near the paper pieces? Why does this happen?

2.   Draw a free body diagram of the forces acting on the piece of paper.

3.   Why does the electric force easily overcome the force of gravity and lift the paper off the surface without even touching the paper?

4.   Which of the materials pick up positive charge and which pick up negative charge? How did you determine this?

Experiment #2: An experiment run found that the two enantiomers of Isoflurane do not act the same as anesthetics, in that it took a smaller amount of one to produce the same anesthetic effect as the other. What is a chiral receptor? What roles do chiral receptors play in biological systems? Does the fact that the two enantiomers of Isoflurane do not act the same support or disprove the hypothesis listed above? Explain your answer

Experiment 2: Hematocrit In the second experiment, you will determine hematocrit for all students in the class to answer the research question: Is there a difference in hematocrit between male and female college students?

a. What basic type of study design will you use to answer the research question?

a) descriptive b) experimental c) neither

b.  More specifically, what type of study design will you use to answer the research question?

a) case study b) cross-over c) cross-sectional d) longitudinal e) pre/post f) randomized, controlled g) retrospective h) time series

c. What type of statistical test would be most appropriate to analyze these data?

a) Chi-square test b) dependent t-test c) independent t-test d) one-way ANOVA e) repeated measures ANOVA f) None of these is appropriate. g) You cannot run statistics on these data.

d. What is(are) the control(s)? Choose ANY that apply.

a) altitude of testing site b) hydration status of subjects c) sex of subjects d) training status of subjects e) There is none.

diffusion experiment: my experiment was to cut an agar cube into 64 pieces and place it into different volumes of water. we placed it into 200 mL ( slope of 24) , 600 mL (slope of 12) , and 800 mL (slope of 8). The slope is from the graph, its rate of diffusion graph from each volume.

a. which had the largest affect on the rate of diffusion?

b) Based on your experiments, discuss at least two adaptations that affect diffusion in living organisms (physiological, structural, or behavioral features that evolved due to a selective advantage that was based on diffusion) . Do these match with the factors you identified in a?

Dumas Method Experiment:

In this experiment, we measured a flask with an aluminum foil and elastic band set up then added 4mL of methanol inside the flask and sealed with the foil covering and boiled in a water bath until all the liquid vaporized (this will drive out any air in the flask and push out all excess vapour). Then we cooled it to let the vapour condense and reweighed the flask with the vapour in it. The following questions pertain to the experiment:

For each of the following experimental conditions determine whether the calculated value for molar mass would be: A) too high B) Too low C) Unaffected. In each case, explain how this result occurs.

a) After removing he flask from the water bath, the experimenter cools the flask to room temperature but does not dry it. The calculated molar mass will be: A) too high B) Too low C) Unaffected. Explain.

b) The flask is removed from the water bath containing vapour only, the experimenter cools the flask to room temperature and some vapour condenses inside the flask. The calculated molar mass will be:  A) too high B) Too low C) Unaffected. Explain.

c) The flask volume is not measured; instead the experimenter assumes the flask volume to be exactly 125.0 mL. The calculated molar mass will be:  A) too high B) Too low C) Unaffected. Explain.

d) From the time the mass of the unused flask assembly (flask, foil and elastic band) is recorded the flask is handled several times with oily fingers. The calculated molar mass will be A) too high B) Too low C) Unaffected. Explain.

search the internet for the Stanford Experiment and see the different perspective about this experiment afer viewing the video, if you have been a guard, do you think you would have been more likely to go along with the other guards or would you have resisted or spoken up about treating the prisoners the way you would have wanted to be treated if the roles had been reversed??