The following reaction is used to generate hydrogen gas in the laboratory.If 243 mL of gas is collected at 25°C and has a total pressure of 745 mm Hg,what mass of hydrogen is produced? A possibly useful table of water vapor pressures is provided below. Mg(s) + 2 HCl(aq) → MgCl₂(aq) + H₂(g) T (°C) P (mm Hg)
20 17.55
25 23.78
30 31.86

Question

Quizplus · Accepted Answer

To find the mass of hydrogen gas, first calculate the pressure of dry hydrogen gas by subtracting the water vapor pressure at 25°C (23.78 mm Hg) from the total pressure (745 mm Hg). Then, use the ideal gas law (PV = nRT) to find the number of moles of hydrogen gas, and finally convert moles to grams using the molar mass of hydrogen (2.02 g/mol).

The Following Reaction Is Used to Generate Hydrogen Gas in the Laboratory.If