Question

2. A 0.0758 gram sample of aluminum metal was reacted with dilute sulfuric acid and the hydrogen evolved was collected over mercury at a barometric pressure of 737 torr and a temperature of 23 C. What volume of dry hydrogen gas was collected? PV-nRT Co.0628)0.03 206) (296.15) 6.0758g - 6.0028 26.8 N-0.070L 273.15+23246.s (a 0,4 at 3. A 0.605 g sample of a certain metal, X, reacts with hydrochloric acid to form XCI3 and 450 mL of hydrogen gas collected over water at 25°C and 740 mm Hg pressure. What is the molar mass of X? tat .44 n C0.0) Lo.usOL) Lo.09i06 286) 0.0 18mol PT Dilute hydrochloric acid is added to a 0.500 g sample of an alloy containing zinc and copper. The gas evolved is collected over water using an apparatus like the one used in Experiment 14. The following data were obtained: 4. you 135

Answer 1

3)

V = 450 mL = 0.450 L

T =25 +273 = 298 K

P = 740 mmHg = 0.974 atm

P V = n R T

0.974 x 0.450 = n x 0.0821 x 298

n = 0.0179

moles of H2 = 0.0179

2 X      + 6 HCl ----------------------> 2 XCl3 + 3 H2

3 moles H2 --------------------> 2 moles X

0.0179 moles H2 ------------> ??

moles of X = 2 x 0.0179 / 3 = 0.01194

moles of X = 0.01194

mass of X = 0.605 g

moles = mass / molar mass

0.01194 = 0.605 / molar mass

molar mass = 50.7 g / mol

molar mass of X = 50.7 g /mol