Skip to main content
Pearson+ LogoPearson+ Logo
Ch.13 - Solutions & Their Properties
All textbooksMcMurry 8th EditionCh.13 - Solutions & Their PropertiesProblem 149a
Chapter 13, Problem 149a

Treatment of 1.385 g of an unknown metal M with an excess of aqueous HCl evolved a gas that was found to have a volume of 382.6 mL at 20.0 °C and 755 mm Hg pressure. Heating the reaction mixture to evaporate the water and remaining HCl then gave a white crystalline compound, MClx. After dissolving the compound in 25.0 g of water, the melting point of the resulting solution was - 3.53 °C. (b) What mass of MClx is formed? (a) How many moles of H2 gas are evolved?

Verified step by step guidance
1
Step 1: Use the ideal gas law to calculate the number of moles of H2 gas evolved. The ideal gas law is given by PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature in Kelvin.
Step 2: Convert the given pressure from mm Hg to atm by using the conversion factor 1 atm = 760 mm Hg. Then, convert the temperature from Celsius to Kelvin by adding 273.15 to the Celsius temperature.
Step 3: Substitute the values of P (in atm), V (in liters), R (0.0821 L·atm/mol·K), and T (in Kelvin) into the ideal gas law equation to solve for n, the number of moles of H2 gas.
Step 4: To find the mass of MClx formed, use the freezing point depression formula: ΔTf = i * Kf * m, where ΔTf is the change in freezing point, i is the van't Hoff factor, Kf is the freezing point depression constant for water (1.86 °C·kg/mol), and m is the molality of the solution.
Step 5: Calculate the molality (m) of the solution using the change in freezing point and the given mass of water. Then, use the molality to find the moles of MClx, and finally, calculate the mass of MClx using its molar mass.

Verified Solution

Video duration:
3m
This video solution was recommended by our tutors as helpful for the problem above.
Was this helpful?
Related Practice
Textbook Question
Elemental analysis of b@carotene, a dietary source of vitamin A, shows that it contains 10.51% H and 89.49% C. Dissolving 0.0250 g of b@carotene in 1.50 g of camphor gives a freezing- point depression of 1.17 °C. What are the molecular weight and formula of b@carotene? [Kf for camphor is 37.7 1°C kg2>mol.]
545
views
Open Question
The steroid hormone estradiol contains only C, H, and O; combustion analysis of a 3.47 mg sample yields 10.10 mg CO2 and 2.76 mg H2O. When dissolving 7.55 mg of estradiol in 0.500 g of camphor, the melting point of camphor is depressed by 2.10 °C. What is the molecular weight of estradiol, and what is a probable formula? [For camphor, Kf = 37.7 °C kg/mol.]
Textbook Question
Addition of 50.00 mL of 2.238 m H2SO4 1solution density = 1.1243 g>mL2 to 50.00 mL of 2.238 M BaCl2 gives a white precipitate. (b) If you filter the mixture and add more H2SO4 solution to the filtrate, would you obtain more precipitate? Explain.
365
views
Textbook Question

Treatment of 1.385 g of an unknown metal M with an excess of aqueous HCl evolved a gas that was found to have a volume of 382.6 mL at 20.0 °C and 755 mm Hg pressure. Heating the reaction mixture to evaporate the water and remaining HCl then gave a white crystalline compound, MClx. After dis- solving the compound in 25.0 g of water, the melting point of the resulting solution was - 3.53 °C. (c) What is the molality of particles (ions) in the solution of MClx?

329
views
Textbook Question

Treatment of 1.385 g of an unknown metal M with an excess of aqueous HCl evolved a gas that was found to have a volume of 382.6 mL at 20.0 °C and 755 mm Hg pressure. Heating the reaction mixture to evaporate the water and remaining HCl then gave a white crystalline compound, MClx. After dis- solving the compound in 25.0 g of water, the melting point of the resulting solution was - 3.53 °C. (e) What are the formula and molecular weight of MClx?

292
views
Textbook Question

Treatment of 1.385 g of an unknown metal M with an excess of aqueous HCl evolved a gas that was found to have a volume of 382.6 mL at 20.0 °C and 755 mm Hg pressure. Heating the reaction mixture to evaporate the water and remaining HCl then gave a white crystalline compound, MClx. After dis- solving the compound in 25.0 g of water, the melting point of the resulting solution was - 3.53 °C. (f) What is the identity of the metal M?

411
views