Solved: In a certain experiment, magnesium boride (Mg3B2)

Chapter 5, Problem 5.87

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In a certain experiment, magnesium boride (Mg3B2) reacted with acid to form a mixture of four boron hydrides (BxHy), three as liquids (labeled I, II, and III) and one as a gas (IV). PVDWause R 0.08206 atm L mol K b NaHCO3(s) H (aq) H2O(l) CO2(g) Na (aq) 2NaHCO3(s) Na2CO3(s) H2O(l) CO2(g) 230 Chapter 5 Gases and the Kinetic-Molecular Theory siL48593_ch05_186-234 8:27:07 09:11pm Page 230 nishant-13 ve403:MHQY042:siL5ch05: Apago PDF Enhancer (a) When a 0.1000-g sample of each liquid was transferred to an evacuated 750.0-mL container and volatilized at 70.00 C, sample I had a pressure of 0.05951 atm; sample II, 0.07045 atm; and sample III, 0.05767 atm. What is the molar mass of each liquid? (b) Boron is 85.63% by mass in sample I, 81.10% in II, and 82.98% in III. What is the molecular formula of each sample? (c) Sample IV was found to be 78.14% boron. Its rate of effusion was compared to that of sulfur dioxide and under identical conditions, 350.0 mL of sample IV effused in 12.00 min and 250.0 mL of sulfur dioxide effused in 13.04 min. What is the molecular formula of sample IV?