ACID/BASE PRACTICE PROBLEMS

(a) 3 moles of sodium nitrate are placed in 1 L of water. Calculate the pH.

(b) Calculate the Ka and the % ionization of a weak acid if 0.02 moles of the acid is added to 1 L water and makes a solution with a pH of 4.75.

(c) A solution containing 0.2 moles of NaOH, 0.3 moles of HCl, and 0.1 moles of HF (Ka=7.1e-4) is added to 1 L of water. Calculate the pH and pOH.

(d) 0.2 moles of the salt acid of urea is added to 1 L of water, calculate the pH of the solution.

A.

Do you expect an echo to return to you more quickly or less quickly on a hot day, as compared to a cold day?

1. more quickly on a hot day

2. equal times on both days

3. more quickly on a cold day

B.

If you fill your lungs with helium and then try talking, you sound like Donald Duck. What conclusion can you reach about the speed of sound in helium?

1. speed of sound is less in helium

2. speed of sound is the same in helium

3. speed of sound is greater in helium

4. this effect has nothing to do with the speed in helium

C.

You hear a fire truck with a certain intensity, and you are about 1 mile away. Another person hears the same fire truck with an intensity about 10 times less. Roughly, how far is the other person from the fire truck?

1. about the same distance

2. about 3 miles

3. about 10 miles

4. about 30 miles

5. about 100 miles

D.When Minnie talks, she creates a sound level of 60 dB at your location. Mickey talks with the same volume, also giving 60 dB at your location. If both Minnie and Mickey talk simultaneously from the same spot, what would be the new sound level that you hear? (±0.1 dB)

E.Consider an idealized model with a bird emitting constant sound power, with intensity inversely proportional to the square of the distance from the bird. How many decibels does the sound level drop when you move 2.6 times as far away from the bird?

F.

You have a long pipe and a short pipe. Which one has the higher frequency?

1. the long pipe

2. the short pipe

3. both have the same frequency

You blow into an open pipe and produce a tone. What happens to the frequency of the tone if you close the end of the pipe and blow into it again?

1. depends on the speed of sound in the pipe

2. you hear a higher frequency

3. you hear the same frequency

4. you hear a lower frequency

Cincinnati Paint Company sells quality brands of paints through hardware stores throughout the United States. The company maintains a large sales force who call on existing customers and look for new business. The national sales manager is investigating the relationship between the number of sales calls made and the miles driven by the sales representative. Also, do the sales representatives who drive the most miles and make the most calls necessarily earn the most in sales commissions? To investigate, the vice president of sales selected a sample of 25 sales representatives and determined:

• The amount earned in commissions last month (y)
• The number of miles driven last month (x₁)
• The number of sales calls made last month (x₂)

The information is reported below.

  Click here for the Excel Data File

Develop a regression equation including an interaction term. (Negative amount should be indicated by a minus sign. Round your answers to 3 decimal places.)

Complete the following table. (Negative amounts should be indicated by a minus sign. Round your answers to 3 decimal places.)

Compute the value of the test statistic corresponding to the interaction term. (Negative amount should be indicated by a minus sign. Round your answer to 2 decimal places.)

At the 0.05 significance level is there a significant interaction between the number of sales calls and the miles driven?

1) Researchers wish to test the efficacy of a program intended to reduce the length of labor in childbirth. The accepted mean labor time in the birth of a first child is 15.3 hours. The mean length of the labors of 13 firsttime mothers in a pilot program was 8.8 hours with standard deviation 3.1 hours. Assuming a normal distribution of times of labor, test at the 10% level of significance test whether the mean labor time for all women following this program is less than 15.3 hours.

2) Six coins of the same type are discovered at an archaeological site. If their weights on average are significantly different from 5.25 grams then it can be assumed that their provenance is not the site itself. The coins are weighed and have mean 4.73 g with sample standard deviation 0.18 g. Perform the relevant test at the 0.1% (1/10th of 1%) level of significance, assuming a normal distribution of weights of all such coins.

3) An economist wishes to determine whether people are driving less than in the past. In one region of the country the number of miles driven per household per year in the past was 18.59 thousand miles. A sample of 15 households produced a sample mean of 16.23 thousand miles for the last year, with sample standard deviation 4.06 thousand miles. Assuming a normal distribution of household driving distances per year, perform the relevant test at the 5% level of significance.

4) The average number of days to complete recovery from a particular type of knee operation is 123.7 days. From his experience a physician suspects that use of a topical pain medication might be lengthening the recovery time. He randomly selects the records of seven knee surgery patients who used the topical medication. The times to total recovery were:

128,135,131,142,136,151,133.

a) Assuming a normal distribution of recovery times, perform the recovery test of hypotheses at the 10% level of significance.

b) Would the decision be same at the 5% level of significance? Answer either by constructing a new rejection region (critical value approach) or by estimating the p-value of the test in part(a) and comparing it.  

For the given reports, are the given values of the correlation coefficient reasonable?

1. A) A correlation of r = +0.7 between gender and height.

i) Reasonable ii) Unreasonable

1. B) A correlation of r = +1.0 between outdoor temperature and sales of ice cream.

i) Reasonable ii) Unreasonable

1. C) A correlation of r = 0 between shoe size and IQ scores in a study of adults.

i) Reasonable ii) Unreasonable

1. D) A correlation of r = +0.7 between distance from the equator for North American cities and average January temperature.

i) Reasonable ii) Unreasonable

1. E) A correlation of r = -0.8 between outside temperature and sales of hot chocolate.

i) Reasonable ii) Unreasonable

(Round all intermediate calculations to at least 4 decimal places.) It is advertised that the average braking distance for a small car traveling at 75 miles per hour equals 120 feet. A transportation researcher wants to determine if the statement made in the advertisement is false. She randomly test drives 36 small cars at 120 miles per hour and records the braking distance. The sample average braking distance is computed as 111 feet. Assume that the population standard deviation is 20 feet. Use Table 1. a. State the null and the alternative hypotheses for the test. H0: μ = 120; HA: μ ≠ 120 H0: μ ≥ 120; HA: μ < 120 H0: μ ≤ 120; HA: μ > 120 b. Calculate the value of the test statistic and the p-value. (Negative values should be indicated by a minus sign. Round "Test statistics" to 2 decimal places. Round "p-value" to 4 decimal places.) Test statistics p-value The p-value is: 0.01 Picture p-value < 0.025 0.025 Picture p-value < 0.05 0.05 Picture p-value < 0.10 p-value Picture 0.10 p-value < 0.01 c. Use α = 0.01 to determine if the average breaking distance differs from 120 feet. The average breaking distance is different from 120 miles. d. Repeat the test with the critical value approach. (Negative values should be indicated by a minus sign. Round your answers to 3 decimal places.) Critical values are and and we H0.

Statsitics question

This exercise resembles the preceding exercise. The variables in this case are: 1) the gender of automobile drivers, 2) whether they have driven "many" miles in their lives or "few" miles, and 3) whether they have had "many" accidents or "few" accidents.

You are to use the elaboration model to test fully the following hypothesis about the impact of gender on number of automobile accidents:

Hypothesis: Men have more automobile accidents than do women.

In testing this hypothesis, complete the items that follow the data table.

1. Identify the independent and dependent variables in the hypothesis. Construct the bivariate table that tests this basic hypothesis. Be sure you follow the guidelines for effective table presentation and analysis discussed in Chapter 15. Interpret the results.

2. Construct the other two bivariate tables that examine the relationship of the control variable first to the independent variable and then to the dependent variable of the original hypothesis. Interpret the results.

3. Construct the trivariate table appropriate for assessing the effect of the control variable on the original relationship. Do this by presenting two versions of the original bivariate table, one for each attribute of the control variable. Analyze the results.

4. Which form of the elaboration model best represents the pattern of your results? Why?

Martin Galloway, the sole proprietor of a consulting business, has gross receipts of $45,000. His address is: 1223 Fairfield Street, Westfield, New Jersey and his SSN is 158-68-7799. Expenses paid by his business are

During the year, Martin drives his car a total of 15,000 miles (700 business miles and 550 personal miles per month). He paid $100 for business-related parking and tolls. He paid $120 in fines for speeding tickets when he was late for appointments with clients. Martin’s office is located in his home. His office occupies 500 of the 2,000 square feet in his home. His total (unallocated) expenses for his home are

Depreciation for the business portion of his home is $1,364.

1. What is Martin’s net income (loss) from his business for 2018?
2. How much self-employment tax must Martin pay?
3. Based on this information, are there any other deductions that Martin can claim on his individual tax return other than those reported on his Schedule C?
4. How would your answers to the above items change if Martin elects to use the simplified method for home office expenses?

1. Select a car that has a traditional gas-engine model and a hybrid or electric model (i.e. Honda Civic). Make the assumption that the car will be driven for five years and the annual miles driven will be 12,000 miles. Then use ten years with the same 12,000 miles per year. Decide on an estimate for the cost per gallon of gas (i.e. truck will cost more than a compact car). 2. Research the initial cost of the traditional gas-engine and the hybrid or electric model. Be sure to include all the upfront cost including taxes. You do not need to do both hybrid or electric. You can pick one to compare against the gas-engine model. If you find a car that has all three model types and you compare all three, that will be extra credit. Then estimate the annual operating cost (fuel cost, insurance, maintenance, etc.). Calculate the present value of the cost of owning this vehicle with the gas-engine vs. the hybrid or electric model. Use a 6% discount rate. Then use a 10% discount rate. Does that make any difference? 3. Compare the cost of the two or three models. After comparing the costs, research the environmental issues associated with the two or three car models. Incorporate any sustainability issues on both sides. Formulate arguments to support your recommendation for the gas-engine or hybrid/electric model. Debate which model is more desirable for businesses to buy. Be specific in your reasons and cite your information sources.