A. A 13.98 gram sample of an organic compound containing C, H and O is analyzed by combustion analysis and 20.85 grams of CO₂ and 6.402 grams of H₂O are produced.

In a separate experiment, the molar mass is found to be 118.1 g/mol. Determine the empirical formula and the molecular formula of the organic compound.

• Enter the elements in the order C, H, O
  

  empirical formula =

  molecular formula =

B. When 2.543 grams of a hydrocarbon, C_xH_y, were burned in a combustion analysis apparatus, 7.979 grams of CO₂ and 3.267 grams of H₂O were produced.

In a separate experiment, the molar mass of the compound was found to be 28.05 g/mol. Determine the empirical formula and the molecular formula of the hydrocarbon.

• Enter the elements in the order presented in the question.
  

  empirical formula =

  molecular formula =

1. A marketing expert working for Macey’s grocery store wishes to know the average number of times wallmart customers visit the store each week. In order to address this question, she chooses three different hours on Saturdays during which she stands outside the grocery store and talks to customers as they enter to do their shopping.

1. State the population(s) of interest.

2. Identify the parameter(s) of interest.

3. Why is the parameter not ‘the number of times each person visits Macey’s in a week’?

4. Is this an observational study or a controlled experiment? Explain.

5. What type of analysis does this anticipate?

6. If applicable, identify one problem with the sampling scheme and explain how this would bias the results of the experiment. Otherwise, explain why you think the sampling is well done.

ANSWER WITH A GENERAL IDEA/MECHANISM RATIONALE

Huntingtin is a disease gene linked to Huntington's disease, a neurodegenerative disorder characterized by loss of striatal neurons. How would you design a peptide that could prohibit the loss of the neurons? Describe your rational for the design of the peptide. In detail:

1. What target sequences would you need to target the peptide to the correct location in the cell. Explain your choice.

2. What other sequences would you need for the peptide to be effective in Huntington’s disease? Explain your choices.

3. How would you express the peptide in the cells? Design your experiment.

4. How would you prove that your peptide is functioning? Design a basic experiment to test the effectiveness of your peptide.

Q1) why did you have two different indicators in this expriment rather than just phenolphthalein or just methyl orange?

Q2) Was it necessary to use a dry Erlenmeyer flask to prepare the unknown sample for titration or was it okay if the flask was left slightly wet with distilled water after you washed it and before you placed your sample in it? Explain.

Q3) Using your textbook as a resource, suggest two alternative pH indicators that could be used for this experiment instead of phenolphthalein and methyl orange. Explain your choice.

Q4) If the pH indicator used for the titration in step 1 changed color at a lower pH than phenolphthalein what effect would it have on the mass and what percent of the sodium carbonate determined in this experiment? Explain.

1.

Suppose you perform an experiment that consists of rolling two dice and

recording their sum.

a. What is the sample space of this experiment?

b. Find the probability that the sum is either even or more than 9.

c. Find the probability that the sum is odd and a multiple of 3.

d. Find the expected sum.

2.

When Fernando took MAT 257 last semester, he got the same exact score, 85%, in both Test 1 and Test 2. If the class mean and standard deviation for Test 1 were 86% and 4%, respectively, while the class means to score and standard deviation for Test 2 were 86% and 5%, respectively, in which test did Fernando perform relatively better? Explain.

Q1) why did you have two different indicators in this expriment rather than just phenolphthalein or just methyl orange?

Q2) Was it necessary to use a dry Erlenmeyer flask to prepare the unknown sample for titration or was it okay if the flask was left slightly wet with distilled water after you washed it and before you placed your sample in it? Explain.

Q3) Using your textbook as a resource, suggest two alternative pH indicators that could be used for this experiment instead of phenolphthalein and methyl orange. Explain your choice.

Q4) If the pH indicator used for the titration in step 1 changed color at a lower pH than phenolphthalein what effect would it have on the mass and what percent of the sodium carbonate determined in this experiment? Explain.

1. An ad for Crest Whitestrips Premium claims that the strips will whiten teeth in 7 days and the results will last for 12 months. A researcher who wishes to test this claim studies 20 sets of identical twins. Within each set of twins, one is randomly selected to use Crest Whitestrips Premium in addition to regular brushing and flossing, while the other just brushes and flosses. Whiteness of the teeth is measured at the beginning of the study, after 7 days, and every month thereafter for 12 months.
2. 1. What type of experimental design is this?
3. 1. What is the response variable in this experiment?
4. 1. What are the treatments?
5. 1. What are other factors (controlled or uncontrolled) that could affect the response variable?
6. 1. What might be an advantage of using identical twins as subjects in this experiment?

The purpose of this Question is to investigate some of the properties of the binomial probability distribution using Microsoft Excel. a. Suppose that for a binomial experiment with n = 15 trials, the probability of success is p = 0.10, and x is the number of successes. Obtain the probability distribution of x. Make a histogram for the probability distribution and comment on its shape. Find the mean and standard deviation of x. b. Suppose that for a binomial experiment with n = 15 trials, the probability of success is p = 0.50, and x is the number of successes. Obtain the probability distribution of x. Make a histogram for the probability distribution and comment on its shape. Find the mean and standard deviation of x. c. Which of the distributions in parts a–b had the greatest variability in the number of successes? Why does this make sense?

List the criteria for a binomial experiment. (Select all that apply.)

-The probability of success on each trial is constant.

-The trials may have two or more outcomes.

-The trials have exactly three outcomes.

-The trials are mutually exclusive.

-The probability of success can change from trial to trial.

-The trials are independent. The trials have exactly two outcomes.

-A fixed number of trials repeated under identical conditions.

What does the random variable of a binomial experiment measure?

-The random variable measures the number of failures in n trials.

-The random variable measures the number of successes in n trials.

-The random variable measures the number of trials until the 1st success.

-The random variable measures the number of trials until the nth success.