1)A local supermarket claims that the waiting time for its customers to be served is the lowest in the area. A competitor's supermarket checks the waiting times at both supermarkets. The sample statistics are listed below. Test the local supermarket's hypothesis. Use a= 0.05.

A) Hypothises:

B) Critical Values t-critical

C) Test statistic t-stat and the decision to reject or fail to reject

D) The conclusion about the decision

21. What is the cell potential for the following cells at 25°C?

a. Pb(s) | Pb2+ (aq) (1.0 M) || Cu2+ (aq) (1.0x10-4 M) | Cu(s)

b. Pt(s) | Sn2+ (aq) (0.001 M), Sn4+(aq) (0.005 M) || Ag+(aq) (0.500 M) | Ag(s)

c. In part a, what will the concentration of Pb2+ be at equilibrium?

22. The following cell has a measured potential of 1.42 V at 25°C: Al (s) | Al3+ (aq) (0.01 M) || Co2+ (aq) (? M) | Co (s)

What is the concentration of the Co2+?

Sickle cell anemia is a recessive disorder caused by a mutation in the hemoglobin A gene. Persons with the disease have a variety of serious health issues related to fragile and sickling red blood cells including premature death, and infants sometimes die from complications. In regions of central Africa where malaria is endemic, the relative fitnesses for individuals that are homozygous for the wild type hemoglobin allele (Hb^A), heterozygous (Hb^AHb^S), and homozygous for the sickle cell allele (Hb^S) are 0.8, 1.0 and 0.1 respectively. The selection coefficient for someone of Central African ancestry who is an Hb^A/Hb^A homozygote born and raised in Chicago would be ____

A random sample of n = 15 heat pumps of a certain type yielded the following observations on lifetime (in years):

Assume that the lifetime distribution is exponential and use an argument parallel to that of this example to obtain a 95% CI for expected (true average) lifetime. (Round your answers to two decimal places.)

( ,    ) years

What is a 95% CI for the standard deviation of the lifetime distribution? [Hint: What is the standard deviation of an exponential random variable?] (Round your answers to two decimal places.)

( , ) years

A random sample of n = 15 heat pumps of a certain type yielded the following observations on lifetime (in years):
2.0 1.2 6.0 1.9 5.1 0.4 1.0 5.3 15.6 0.9 4.8 0.9 12.2 5.3 0.6

a.) Assume that the lifetime distribution is exponential and use an argument parallel to that of this example to obtain a 96% CI for expected (true average) lifetime (round answer to two decimal places)

(________, _________) years

c.) What is a 95% CI for the standard deviation of the lifetime distribution?
(_______, _______) years

*You may need to use the appropriate table in the Appendix of Tables to answer this question.

Q.26

Estimate the value of the equilibrium constant at 620 K for each of the following reactions. ΔG∘f for BrCl(g) is −1.0 kJ/mol. The standard molar entropy, S∘, for BrCl(g) is 240.0 J/mol⋅K.

Part A

2NO2(g)⇌N2O4(g). ΔH∘f for N2O4(g) is 9.16 kJ/mol.

Express your answer using three significant figures.

Part B

Br2(g)+Cl2(g)⇌2BrCl(g) .ΔH∘f for BrCl(g) is 14.6 kJ/mol.

Express your answer using three significant figures.

answer both pls

1. Consider the following half-reaction.
4H⁺(aq) + O₂(g) + 4e^- → 2H₂O(l)      E^o = 1.23 V
What is E, if the pressure of oxygen gas is 1.0 atmosphere and the pH is 2.92?
USE 2 DECIMAL PLACES. (Hint, are solids and pure liquids included in Q? Using LeChatelier's principle is E going to be larger or smaller?)

2. Mg₂C₂O₄(s) → 2Mg²⁺(aq) +C₂O₄^2-(aq) K_sp = 8.6 x 10^-5
What is Q_sp if 100 mL of 0.080 M Mg(N0₃)₂ is added to 50 mL of 0.032 M Na₂C₂O₄?

1) 20.0 mL of 0.01 M AgNO3 and 30.0 mL of 0.010 M K2CrO4 are mixed together and allowed to react. Will a precipitate form? What will be the molarities of the silver ion and chromate ion at equilibrium?

2) Tooth enamel is composed of hydroxyapatite, whose simplest formula is Ca5(PO4)3OH and whose corresponding Ksp = 6.8 x 10^-27. As discussed, fluoride in fluorinated water or in toothpaste reacts with the hydroxyapatite to form fluoroapatite, Ca5(PO4)3F whose Ksp = 1.0 x 10^-60.

a) write the expression for the solubility constant for hydroxyapatite and for fluoroapatite.

b) calculate the molarity of each of these compounds.

A 0.1002 g sample containing only CCl4 and CHCl3 was dissolved in methanol and electrolyzed at the surface of a mercury electrode at –1.0 V, which required 50.20 s at a constant current of 0.200 A. The potential of the cathode was then adjusted and held constant at –1.80 V. Completion of the titration at this potential required 382.35 s at a constant current of 0.200 A. Calculate the respective percentages of CCl4 and CHCl3 in the mixture. The electrolysis reactions are given below. 2CCl4 + 2H+ + 2e- + 2Hg(l) → 2CHCl3 + Hg2Cl2(s) [occurs at –1.0V] 2CHCl3 + 6H+ + 6e- + 6Hg(l) → 2CH4 + 3Hg2Cl2(s) [occurs at –1.80V]

A captive James Bond is strapped to a table beneath a huge pendulum made of a 2.0-m-diameter uniform circular metal blade rigidly attached, at its top edge, to a 5.5-m-long, massless rod. The pendulum is set swinging with a 10∘ amplitude when its lower edge is 3.4 m above the prisoner, then the table slowly starts ascending at 1.0 mm/s. After 25 minutes, the pendulum's amplitude has decreased to 7.0∘.Fortunately, the prisoner is freed with a mere 30 s to spare.

What was the speed of the lower edge of the blade as it passed over him for the last time?