Q2.

A 3.82-g sample of magnesium nitride is reacted with 7.73 g of water. \mathrm{Mg}_{3} \mathrm{~N}_{2}+3 \mathrm{H}_{2} \mathrm{O} \rightarrow 2 \mathrm{NH}_{3}+3 \mathrm{MgO} The yield of MgO is 3.60 g. What is the percent yield in the reaction? А. 99.9 В. 46.6 С. 49.4 D. 78.7 Е. 94.5

For the system methane(1)/ethane(2)/propane(3) as a gas, estimate f, f» fx ¢1. Þ2.and 43 at t = 100°C. P 35 bar, y1 =0.21, and y2 = 0.43: (a) Through application of Eq. (10.64). (b) Assuming that the mixture is an ideal solution.

At 25°C, an aqueous solution containing 35.0 wt% H,SO, has a specific gravity of 1.2563. A quantity of the 35% solution is needed that contains 195.5 kg of H2SO4 a. Calculate the required volume (L) of the solution using the given specific gravity. b. Estimate the percentage error that would have resulted if pure-component specific gravities of H SO4(SG = 1.8255) and water had been used for the calculation instead of the given specific gravity of the mixture.

Three different liquidsare used in the manometer shown here. \text { a. Derive an expression for } P_{1}-P_{2} \text { in terms of } \rho_{\mathrm{A}}, \rho_{\mathrm{B}}, \rho_{\mathrm{C}}, h_{1}, \text { and } h_{2} . D. Suppose fluid A is methanol, B is water, and C is a manometer fluid with a specific gravity of 1.37; pressureP = 121.0 kPa; h= 30.0 cm ; and h2 = 24.0 cm. Calculate P (kPa).

3.25. WP A mixture is 10.0 mole% methyl alcohol, 75-0 mole% methyl acetate (C,H60,), and 15.0 mole%acetic acid. Calculate the mass fractions of each compound. What is the average molecular weight of the mixture? What would be the mass (kg) of a sample containing 25.0 kmol of methyl acetate?

An experiment is planned to record the change in pH as a powdered base is added to 50 cm3 dilute hydrochloric acid. The method suggested is step 1add dilute hydrochloric acid up to the 50 cm³ mark on a beaker; step 2 add one spatula of the base and stir; step 3measure the pH of the mixture; step 4 repeat steps 2 and 3 until the pH stops changing. (i) State how you could change the method so that the amounts of dilute hydrochloric acid and of the base can be measured more accurately. dilute hydrochloric acid base (ii) During the experiment the pH changes from 2 to 10. If phenolphthalein indicator is added at the beginning of the experiment, a colour change occurs as the base is added. State the colour change that occurs. colour at start ... colour at end .. (iii) Explain, in terms of the particles present, why the pH increases during the experiment.

1. A student has 100. mL of 0.400 CUSO4(aq) and is asked to make 100. mL of 0.150 M CUSO4(aq) for a spectrophotometry experiment. a. Calculate the volume of 0.400 M CuSO4(aq) required for the preparation. b. The spectrophotometer available to the student has a wavelength range of 400 nm to 700 nm. Whatwavelength should the student use to minimize the interference from the presence of the Co 2+Tions?(aq) The student plans to conduct a spectrophotometric analysis to determine the concentration of Cu2+(aq) ina solution. The solution has a small amount of Co(NO3)2(aq) present as a contaminant. The student is given the diagram below, which shows the absorbance curves for aqueous solution of Co2+(aq) and Cu2+(aq).

. Suppose a similar experiment had been done using 1.0 M H;PO4solution as the acid. What would be the stoichiometric ratio of moles of NaOH: moles of H;PO4 at the intersection of the ascending and descending portions of the graph of such an experiment?

Calculate the mass of lead(II) chloride precipitate produced when 2.57 g of sodium chloride in solutionin a double replacement reaction with excess aqueous lead (II) nitrate. (ans: 6.11 2)

3-8C A househusband is cooking beef stew for his family in a pan that is (a) uncovered, (b) covered with a light lid, and (c) covered with a heavy lid. For which case will the cooking time be the shortest? Why?