Suppose a university teacher wants to know whether or not requiring attendance improves student learning. How could she find out? Describe an experiment that an instructor might actually use. Review the experiments posted by your classmates. Evaluate the pros and cons of their proposals, and when applicable, suggest improvements or ask follow-up questions. (175 words)

Lab: Hydrolysis of polyethylene terephthalate using KOH

1. Why do we need to keep this reaction well stirred?

2. what is the scope of this reaction?

3. IR and NMR interpretation of dimethyl terephthalate

4. What is the role of 1-pentanol and water in this experiment?

5. Explain Alkaline hydrolysis of PET using KOH (in words).

2) Solid aluminum and gaseous oxygen react in a combination reaction to produce aluminum oxide: 4Al (s) + 3O2 (g) → 2Al2O3 (s) In a particular experiment, 5.0 g of Al reacts with 4.0 g of O2.

a) What is the limiting reactant in this reaction?

b) What is the theorectical yield of Al2O3?

c) How much of the excess reactant is left?

In an experiment, 426 g of water is in a copper calorimeter cup of mass 205 g. The cup and the water are at an initial temperature of 10.9 oC. An unknown material with a mass of 361 g at a temperature of 296.1 oC is placed in the water. The system reaches thermal equilibrium at 36.1 oC. What is the specific heat of the unknown material? units = J/kg-C

Limiting reactnt experiment

• What happens, if you will not stir the reaction mixture while heating on hot plate?
• What would be the effect, if you will add tap water instead of deionized water into the salt mixture?
• How will you identify the limiting reagent?
• What technique will you use to separate the un-reacted chemical from the reaction mixture?

A) Threats to the validity of an experiment: Confounding variables/ confounds

Explain each of these three confounds, and the measures that are used to prevent them. The text does not identify #2 and #3 as confounds, but they are.

Confounding variable / Preventive measure

1. Participant bias / Blind the participants

2. Experimenter bias /Double-blind study

3. Participant characteristics /Random assignment

Python program that simulates the rolling a die until the number 5 is first obtained. Repeat the experiment 10,000 times and print out the “Average Number of Rolls to Obtain a Six on a Die”, along with the average value. Include the average number of rolls your program calculates as a comment

Please use comments to better explain what is happening

At very high temperature can following reaction occur.

2 CrSO₄(s) ↔ Cr₂O₃(s) + SO₂(g) + SO₃(g)

Rate constant (K_p) is 0,36 with some temperature. In some experiment a CrSO₄ is put in some container were partial pressure of SO₃ is 1,00 atm. What is partial pressure of SO₂ at equilibrium?

You want to study how a spinach sucrose transporter is regulated during plant development. Propose one experiments that seek to understand one regulatory mechanism that might be involved. Made sure to include the following: what your experiment seeks to specifically understand? What are your controls and why each is needed? And, what are your expected results?