in the experiment, a vitamin C tablet was dissolved in water and diluted to 100 ml. A student took 50 ml of solution to titrate. The titration volume of 0.025 M KIO3 (aq) was 15.8 ml. Calculate the ascorbic acid content per tablet. The molar mass of vitamin C is 176 g/mol

IO3- + 5I- + 6H+ = 3I2 + H20 C6H8O6 + I2 = C6H8O6 + 2I- + 2H+

According to the experiment, whihc of the following is correct

a) vitamin c is also called ascorbic acid

b) Iodide ion I- react with stgarch indicator to form the complex

c) Vitamin C is an ionic compound and soluble in water

d) vitamin C is used as a reducing agent

Net Primary Production (NPP) in ecosystems can be controlled either by limiting resources for photosynthetic (autotroph) organisms, such as nutrients, light, and temperature, or by the abundance of herbivores (primary consumers), which in turn may be controlled by predators (secondary consumers). The first scenario is called bottom-up control of NPP and the second top-down control.

1. Consider the saltwater ecosystem. Define the three important trophic levels. What are the most important photosynthetic organisms, herbivores, and carnivores in the saltwater ecosystem?
2. Outline an experiment to determine if NPP in the saltwater ecosystem is controlled bottom-up or top-down. What is the main variable to be measured in your experiment? What are your experimental treatments? Include controls and replication.

Problem 1:Let’s discuss some particle physics. In 1897, physicist J.J. Thomson conducted a seminalexperiment with a cathode ray tube. In the experiment, a beam of an unknown particle of chargeqandmassmis shot through the tube onto a fluorescent screen, at some speedvand in thex-direction. Uponimpact the beam leaves a bright spot on the screen. Sincevis very fast, effects of gravity are negligible andthe beam forms essentially a straight line normal to the screen.

(a) A uniform nonzero electric field−→E=Eˆzis then turned on by parallel plates of edge lengthLinsidethe tube. As the beam passes between the plates, it experiences deflection due to the electric force andemerges out of the plates by some displacement ∆z. What is ∆z?

(b) To eliminate this deflection, an external uniform magnetic field of magnitudeBis turned on as well.What should be the direction and magnitudeBof this field such that ∆z= 0?

(c) By using the results in parts (a) and (b), we can find the ratio|q|/mof the unknown particle. Whatis|q|/m?

(d) When Thomson conducted his experiment, it was still believed that the atom was the smallest unit ofmatter, making the hydrogen cation the lightest charged particle known back then. When Thomsonconducted his experiment, however, the|q|/mvalue of his mysterious beam was about 1000(!) timeslarger than the|q|/mfor the hydrogen cation. Based on this result, what conclusion can you drawabout the hypothesis that the hydrogen cation is the lightest charged particle?

This experiment was the first discovery of the existence of a subatomic particle. Just for fun, do you knowwhat Thomson’s mysterious particle was? (The chargeqof this particle was measured in a later experimentby Robert A. Millikan in 1909.)

2) I don’t like eating over-ripe bananas, and am interested in understanding the

factors that influence the ripening time of bananas after I bring them home from the store
(which I define as the time until a brown spot appears). I decide to conduct an experiment.
Every Sunday for 8 weeks, I buy a bunch of 6 green/yellow bananas, and record the time
until the first brown spot appears on each banana (so that I end up with 48 measurements on
ripening time). Each week, I try a different combination of methods of storing the bananas
(“treatment”): in a dark cupboard or in the light, with or without an ethylene absorber, and
close to or far away from other produce (fruits and vegetables). The details of my storage
plans are as follows in the below table:

(Week) (Dark/Light) (Ethylene Absorber?) (Close to Other Produce?)
1 Dark Yes Yes
2 Dark Yes No
3 Dark No Yes
4 Dark No No
5 Light Yes Yes
6 Light Yes No
7 Light No Yes
8 Light No No

a. What are the factors in this experiment, and what are the corresponding levels?

b. What are the individuals in this experiment?

c. Is this a randomized controlled experiment? Explain.

d. I find that the bananas that I stored in the dark with an ethylene absorber away from other
produce had a longer ripening time than the bananas in other bunches. Would you suspect
that this storage method causes longer ripening time, or that a confounding factor was at
play? Explain and, if the latter, provide a plausible example of such a factor.

e. Suggest an improvement to my experimental design (other than increasing my sample
size).

The dissolution of calcium hydroxide has a solubility product, Ksp of 5.5 X10^-6at 298 K. The standard enthalpy change is -985.2 kJ/mole and the standard entropy change is 83.4 J/mol.K

1. Write the balanced equation for this dissolution.

2. Write out the equilibrium expression for this process.

3. Find the pH of a saturated solution of calcium hydroxide.

4. What is the standard change in Gibbs Free energy for the dissolution process?

5. You walk into the lab where you are asked to determine the identity of two solutions of the same concentration. You know one is calcium hydroxide and the other is sodium nitrate.  All you have is a thermometer and access to a hot plate and ice.  Outline an experiment that would help you determine the identity of the two solutions. What is the expected outcome based upon what you design?

Problem 3

Hydrogen gas reduces nitrogen oxide to nitrogen gas plus gaseous water in a reaction.

1. Write the balanced equation for the reation.

2. The reaction rates of four initial mixtures of nitrogen gas and nitrogen oxide were measured at 900 ᵒC.  The results are presented in the table below.

Determine the rate law for this reaction at 900ᵒ C.

3. Determine the rate constant at 900ᵒ C.

4. After 180 seconds, what is the concentration of nitrogen oxide gas? Use data from experiment 4.

5. What is the partial pressure of nitrogen oxide gas after the 180 seconds if the volume of the container is 500 mL.  Again use data from experiment 4.

Suppose that you want to measure the causal effect of hours spent studying on the performance on a microeconomics test for a class of 30 students.

Which of the following could be an ideal randomized controlled experiment to study the desired causal​ effect?

A.

Allow the fifteen students with the highest grades in the class an extra day to study for the microeconomics test. Then measure the test score differences between students who got the extra day to study and those that did not.

B.

Allow all students an extra day to study for the microeconomics test. Then measure the test score difference between the student with the highest score and lowest score respectively.

C.

Allow fifteen​ students, chosen at​ random, an extra day to study for the microeconomics test. Then measure the test score differences between students who got the extra day to study and those that did not.

D.

All of the above could be ideal randomized controlled experiments.

Consider the following randomized controlled​ experiment:

You allow fifteen​ students, chosen at​ random, an extra day to study for the microeconomics​ test, and then measure the score differences between those who got the extra day to study and those that did not.

Which of the following could be impediments to implementing this experiment in​ practice?

A.

It could be costly to administer the same test to two different groups of students in the same class on different days.

B.

It could be considered unethical to allow some students more time to study.

C.

It could be against school policy to administer the same test to two different groups of students in the same class on different days.

D.

A and C only.

E.

All of the above could be impediments to implementing this experiment in practice.

To illustrate the effects of driving under the influence of alcohol, a police officer brought a DUI simulator to a local high school. Student reaction time in an emergency was measured with unimpaired vision and also while wearing a pair of special goggles to simulate the effects of alcohol on vision. For a random sample of nine teenagers, the time (in seconds) required to bring the vehicle to a stop from a speed of 60 miles per hour was recorded. Complete parts (a) and (b). Note: A normal probability plot and boxplot of the data indicate that the differences are appromixately normally distributed with no outliers.

(a) Whether the student had unimpaired vision or wore goggles first was randomly selected. Why is this a good idea in designing the experiment?

A)This is a good idea in designing the experiment because it controls for any "learning" that may occur in using the simulator.

B)This is a good idea in designing the experiment because reaction times are different

C) This is a good idea in designing the experiment because the sample size is not large enough

(b) Use a 95% confidence interval to test if there is a difference in braking time with impaired vision and normal vision where the differences are computed as "impaired minus normal"

The lower bound is ______

The upper bound is _______

(Round to the nearest thousandth as needed)

State the appropriate conclusion

A)There is sufficient evidence to conclude there is a difference in braking time with impaired vision and normal vision

B)There is insufficient evidence to conclude there is a difference in braking time with impaired vision and normal vision

Experiment 2

QUESTIONS:::PLEASE ANSWER ALL QUESTIONS AS THEY GO TOGETHER. Everytime questions that go together get split up and not answered i have to repost and other people dont know how to answer questions so my questions get wasted and incorrect answers from not knowing previous question or answer.

25. How would you know if your results from experiment 2 show that the traits were inherited through Mendelian genetics?

27. Determine the Χ2 value for Experiment 2 using the following equation. Record your answer for use in a later question. Show your work.

28. Use the degrees of freedom and Χ2 value from earlier questions to determine the p value for Experiment 2 using the table of critical values for Χ2. Record your answer for use in a later question.

29. Use the hypothesis, degrees of freedom, Χ2, and p value determined in earlier questions to conclude whether corn #2 is following Mendelian genetics. Explain your reasoning.

To illustrate the effects of driving under the influence​ (DUI) of​ alcohol, a police officer brought a DUI simulator to a local high school. Student reaction time in an emergency was measured with unimpaired vision and also while wearing a pair of special goggles to simulate the effects of alcohol on vision. For a random sample of nine​ teenagers, the time​ (in seconds) required to bring the vehicle to a stop from a speed of 60 miles per hour was recorded. Complete parts​ (a) and​ (b). ​Note: A normal probability plot and boxplot of the data indicate that the differences are approximately normally distributed with no outliers.

Subject   Normal, Xi   Impaired, Yi
1   4.47   5.86
2   4.24   5.67
3   4.58   5.45
4   4.56   5.32
5   4.31   5.90
6   4.83   5.49
7   4.55   5.23
8   5.00   5.61
9   4.79   5.63

​(a) Whether the student had unimpaired vision or wore goggles first was randomly selected. Why is this a good idea in designing the​ experiment?

A.

This is a good idea in designing the experiment because the sample size is not large enough.

B.

This is a good idea in designing the experiment because it controls for any​ "learning" that may occur in using the simulator.

C.

This is a good idea in designing the experiment because reaction times are different.

​(b) Use a​ 95% confidence interval to test if there is a difference in braking time with impaired vision and normal vision where the differences are computed as​ "impaired minus​ normal."

The lower bound is __?__.

The upper bound is __?__.

​(Round to the nearest thousandth as​ needed.)

State the appropriate conclusion. Choose the correct answer below.

There is insufficient evidence to conclude there is a difference in braking time with impaired vision and normal vision.

There is sufficient evidence to conclude there is a difference in braking time with impaired vision and normal vision.