OC userin Physics·3 Nov 201788. Calculate the number of atoms in each sample. a. 14.955 g CT b. 39.733 g S c. 12.899 g Pt d . 97.552 g Sn
OC userin Physics·2 Nov 20175.17 . A light rope is attached to a block with mass 4.00 kg that rests on a frictionless, horizontal surface. The horizontal rope passes over a frictionless, massless pulley, and a block with mass m is suspended from the other end. When the blocks are released, the tension in the rope is 15.0 N. (a) Draw two free-body diagrams: one for each block. (b) What is the acceleration of either block? (c) Find m. (d) How does the tension compare to the weight of the hanging block?
OC userin Accounting·2 Nov 20172-5 What effect does an increase in volume have on- a. Unit fixed costs? b. Unit variable costs? C. Total fixed costs? d. Total variable costs?
OC userin Physics·2 Nov 201731.3. The voltage across the terminals of an ac power supply varies with time according to Eq. (31.1). The voltage amplitude is V = 45.0 V. What are (a) the root-mean-square potential differ- ence Vrms and (b) the average potential difference Vay between the two terminals of the power supply?
OC userin Chemistry·31 Oct 2017114. The A — first-order integrated rate law for the reaction products is derived from the rate law using calculus: Rate = k[A] (first-order rate law) d[A] Ratedt [A] =- [A] The equation just given is a first-order, separable differential equation that can be solved by separating the variables and inte- grating: d[A] = -kdt TAJ PINA[A] - kat JA), [A] kat In the integral just given, [A]o is the initial concentration of A. We then evaluate the integral: [In[A]] A) = -k[t]6 In[A] - In[A]o = -kt In[A] = -kt + In[A]o (integrated rate law) a. Use a procedure similar to the one just shown to derive an in- tegrated rate law for a reaction A — products, which is one- half order in the concentration of A (that is, Rate = k[A]"). b. Use the result from part a to derive an expression for the half- life of a one-half-order reaction.
OC userin Chemistry·1 Nov 2017100. Silver can be electroplated at the cathode of an electrolysis cell by the half-reaction: Ag+ (aq) + Ag(s) What mass of silver would plate onto the cathode if a current of 6.8 A flowed through the cell for 72 min?
OC userin Physics·31 Oct 201742. Given the values of AHxn, ASxn, and T, determine ASunty and predict whether or not each reaction is spontaneous. (Assume that all reactants and products are in their standard states.) a. AHix = -95 kJ; ASix = -157J/K; T = 298 K b. AHix = -95 kJ; ASix = -157J/K; T = 855 K C. AHxn = +95 kJ; ASix = -157J/K; T = 298 K d. AHX = -95 kJ; ASXn = +157J/K; T = 398 K
OC userin Chemistry·31 Oct 201780. Consider the reaction: 2 NO(g) + O2(g) = 2 NO2(8) The following data show the equilibrium constant for this reac- tion measured at several different temperatures. Use the data to find A Hexn and ASixn for the reaction. Temperature 170 K. 3.8 x 10-3 180 K 0.34 190 K 18.4 200 K 681
OC userin Physics·31 Oct 201797. The ratio of oxygen to carbon by mass in carbon monoxide is 1.33:1.00. Find the formula of an oxide of carbon in which the ratio by mass of oxygen to carbon is 2.00:1.00.
OC userin Chemistry·1 Nov 2017105. Consider the unbalanced redox reaction: MnO4 (aq) + Zn(s) — Mn2+ (aq) + Zn2+ (aq) Balance the equation and determine the volume of a 0.500 M KMnO4 solution required to completely react with 2.85 g of Zn.
OC userin Chemistry·30 Oct 2017Q6. The Zn/Zn²+ electrode has a standard electrode potential of E = -0.76 V. How does the relative potential energy of an electron at the Zn/Zn2+ electrode compare to the potential energy of an electron at the standard hydrogen electrode? a) An electron at the Zn/Zn2+ electrode has a higher potential energy than an electron at the standard hydrogen electrode. b) An electron at the Zn/Zn2+ electrode has a lower potential energy than an electron at the standard hydrogen electrode. c) An electron at the Zn/Zn2+ electrode has the same potential energy as an electron at the standard hydrogen electrode. d) Nothing can be concluded about the relative potential energy of an electron at the standard electrode potential.
OC userin Chemistry·30 Oct 201738. Sulfur and fluorine form several different compounds including sulfur hexafluoride and sulfur tetrafluoride. Decomposition of a sample of sulfur hexafluoride produces 4.45 g of fluorine and 1.25 g of sulfur, while decomposition of a sample of sulfur tetra- fluoride produces 4.43 g of fluorine and 1.87 g of sulfur. Calcu- late the mass of fluorine per gram of sulfur for each sample and show that these results are consistent with the law of multiple proportions.
OC userin Physics·29 Oct 201711.30. A vertical, solid steel post 25 cm in diameter and 2.50 m long is required to support a load of 8000 kg. You can ignore the weight of the post. What are (a) the stress in the post; (b) the strain in the post; and (c) the change in the post's length when the load is applied?
OC userin Physics·30 Oct 2017Q1.23 Consider the vector products AX (BXC) and (AXB) Xč. Give an example that illustrates the general rule that these two vector products do not have the same magnitude or direction. Can you choose vectors A, B, and such that these two vector products are equal? If so, give an example.
OC userin Accounting·31 Oct 2017EXERCISE 12-14 Identification of Relevant Costs [L012-1] Kristen Lu purchased a used automobile for $8,000 at the beginning of last year and incurred the following operating costs: Depreciation ($8,000 = 5 years) Insurance ..... Garage rent .......... Automobile tax and license ............ Variable operating cost .......... $1,600 $1,200 $360 $40 $0.14 per mile The variable operating cost consists of gasoline, oil, tires, maintenance, and repairs. Kristen esti- mates that, at her current rate of usage, the car will have zero resale value in five years, so the annual straight-line depreciation is $1,600. The car is kept in a garage for a monthly fee. Required: 1. Kristen drove the car 10,000 miles last year. Compute the average cost per mile of owning and operating the car. 2 Kristen is unsure about whether she should use her own car or rent a car to go on an extended cross-country trip for two weeks during spring break. What costs above are relevant in this decision? Explain. 3. Kristen is thinking about buying an expensive sports car to replace the car she bought last year. She would drive the same number of miles regardless of which car she owns and would rent the same parking space. The sports car's variable operating costs would be roughly the same as the variable operating costs of her old car. However, her insurance and automobile tax and license costs would go up. What costs are relevant in estimating the incremental cost of owning the more expensive car? Explain.
