Which of the following mixtures will be a buffer when dissolved in a liter of water?

Consider three students taking an examination. Their respective probabilities of obtaining the different available grades are shown in Table 1. (a) What is the probability that each will obtain a grade of A? (b) If two students were to receive an A, what is the probability that Jim would be among them?

Table 1. Probabilities of Individual Student Exam Grades*

Student    Grade   

                 A   B     C     D      F

Terry         0.5 0.3 0.1 0.06 0.04

Jim           0.4 0.4 0.1 0.07 0.03

Sam         0.3 0.3 0.3 0.05 0.05

* Assume each examination outcome to be independent.

Question 1  

A single random sample of 16 different cereals is obtained, and the sugar content (in grams of sugar per gram of cereal) is measured for each cereal selected. Those amounts have a mean of 0.295 gram and a standard deviation of 0.168 gram. The amount of sugar in all cereals is assumed to be normally distributed.

Construct a 95% confidence interval estimate of the population mean.

Degrees of freedom =                            [ Select ]                       ["14", "15", "16", "17"]      

t-value =                            [ Select ]                       ["2.131", "2.120", "1.753", "1.746"]         (from the table)

Margin of Error =                            [ Select ]                       ["0.0357", "0.0584", "0.0895", "0.168"]      

95% Confidence Interval =                            [ Select ]                       ["0.2722 < μ < 0.3845", "0.2055 < μ < 0.3845", "0.2055 < μ < 0.3243", "0.2722 < μ < 0.3243"]      

--------------------------------------------

Question 2  

A single random sample of 16 different cereals is obtained, and the sugar content (in grams of sugar per gram of cereal) is measured for each cereal selected. Those amounts have a mean of 0.295 gram and a standard deviation of 0.168 gram. The amount of sugar in all cereals is assumed to be normally distributed.

Use a 0.05 significance level to test the claim of a cereal lobbyist that the mean of all cereals is less than 0.3 gram.

Hypotheses:                            [ Select ]                       ["Ho: μ = 0.3 vs. Ha: μ < 0.3", "Ho: μ = 0.3 vs. Ha: μ > 0.3", "Ho: μ < 0.3 vs. Ha: μ > 0.3", "Ho: μ < 0.3 vs. Ha: μ = 0.3"]      

Type of test:                            [ Select ]                       ["Left-tailed", "Right-tailed", "Two-tailed"]      

t statistic =                            [ Select ]                       ["-0.119", "0.119", "-1.753", "1.753"]         (calculated with formula)

Degrees of freedom =                            [ Select ]                       ["14", "15", "16", "17"]      

significance level =                            [ Select ]                       ["0.01", "0.05"]      

Critical t value =                            [ Select ]                       ["1.753", "-1.753", "2.131", "-2.131"]         (from table 10.1)

Decision:                            [ Select ]                       ["Reject the null hypothesis.", "Do not reject the null hypothesis."]      

Conclusion:                            [ Select ]                       ["We have sufficient evidence to support the claim that the mean for all cereals is less than 0.3 gram.", "We do not have sufficient evidence to support the claim that the mean for all cereals is less than 0.3 gram."]      

Calculate the pH of a buffer system containing 1.0 M CH3COOH and 1.0 M CH3COONa.
a) Using the Henderson-Hasselbalch equation
b) Making no assumptions about quantities (use the quadratic equation)
c) Compare and explain your results in a) and b)
d) What is the pH of a buffer system after the addition of 0.10 moles of gaseous HCl to a 1.0 L of the solution? Assume that the volume of the solution does not change when the HCl is added.
The Ka of CH3COOH is 1.8x10^-5

A 66.0 mL sample of 1.0 M NaOH is mixed with 50.0 mL of 1.0 M H2SO4 in a large Styrofoam coffee cup; the cup is fitted with a lid through which passes a calibrated thermometer. The temperature of each solution before mixing is 23.7 °C. After adding the NaOH solution to the coffee cup, the mixed solutions are stirred until reaction is complete. Assume that the density of the mixed solutions is 1.0 g/mL, that the specific heat of the mixed solutions is 4.18 J/(g •°C), and that no heat is lost to the surroundings. The ΔΗrxn for the neutralization of NaOH with H2SO4 is –114 kJ/mol H2SO4. What is the maximum measured temperature in the Styrofoam cup?

A 64.0 mL sample of 1.0 M NaOH is mixed with 47.0 mL of 1.0 M H2SO4 in a large Styrofoam coffee cup; the cup is fitted with a lid through which passes a calibrated thermometer. The temperature of each solution before mixing is 22.6 °C. After adding the NaOH solution to the coffee cup, the mixed solutions are stirred until reaction is complete. Assume that the density of the mixed solutions is 1.0 g/mL, that the specific heat of the mixed solutions is 4.18 J/(g •°C), and that no heat is lost to the surroundings. The ΔΗrxn for the neutralization of NaOH with H2SO4 is –114 kJ/mol H2SO4. What is the maximum measured temperature in the Styrofoam cup?

Solution A (1.0 M Sucrose) and solution B (1.0 M NaCl) are separated by a dialysis membrane. If the membrane is spontaneously permeable to Sucrose, NaCl, and Water, what is the INITIAL reaction of Sucrose, NaCl, and Water?

A 70.0mL sample of 1.0 M NaOH is mixed with 44.0 mL of 1.0 M H2SO4 in a large Styrofoam cup; the cup is fitted with a lid through which passes a calibrated thermometer. The temperature of each solution before mixing is 23.9 Celcius. After adding the NaOH solution to the coffee cup, the mixed solutions are stirred until reaction is complete. Assume that the density of the mixed solutions is 1.00 g/mL, that the specific heat of the mixed solutions is 4.18 J/(g celcius), and that no heat is lost to the surroundings. The deltaHrxn for the neutralization of NaOH with H2SO4 is -114 kJ/mol H2SO4. What is the maximum measured temperature in the Styrofoam cup?

A 65.0 mL sample of 1.0 M NaOH is mixed with 48.0 mL of 1.0 M H2SO4 in a large Styrofoam coffee cup; the cup is fitted with a lid through which passes a calibrated thermometer. The temperature of each solution before mixing is 24.4°C. After adding the NaOH solution to the coffee cup, the mixed solutions are stirred until reaction is complete. Assume that the density of the mixed solutions is 1.0 g/mL, that the specific heat of the mixed solutions is 4.18 J/(g •°C), and that no heat is lost to the surroundings. The ΔΗrxn for the neutralization of NaOH with H2SO4 is –114 kJ/mol H2SO4.

What is the maximum measured temperature in the Styrofoam cup? ---------

Also, 35.985 is incorrect as they mention at the site, "H₂SO₄ is not the limiting reagent. Remember to consider the stoichiometry of the balanced equation for the reaction".

Suppose that the average number of miles driven by a CSULA students is 15,000 and the standard error is 5000 miles. Find the interval of miles within which 99% of the drivers fall. Please show all your work