a).Find the vapor pressure of water at 29.6 oC. b) Calculate the mass of Mg need
ID: 1057321 • Letter: A
Question
a).Find the vapor pressure of water at 29.6 oC.
b) Calculate the mass of Mg needed to produce 80.0 mL of hydrogen gas at STP.
c) Why must the difference between the water level in the eudiometer tube and the water level in the beaker be measured?
Vapor Pressure (P) of Water at Various Temperatures T, oC P, mmHg T, oC P, mmHg T, oC P, mmHg T, oC P, mmHg 19.0 16.5 25.0 23.8 31.0 33.7 13.0 11.2 14.0 12.0 20.0 17.5 26.0 25.2 32.0 35.7 21.0 18.7 27.0 26.7 15.0 12.8 33.0 37.7 16.0 13.6 22.0 19.8 28.0 28.3 34.0 39.9 17.0 14.5 23.0 21.1 29.0 30.0 35.0 42.2 36.0 44.6 18.0 15.5 24.0 22.4 30.0 31.8Explanation / Answer
b) ATt STP, 1 mole of H2 gas occupies 22.4 Litres.
Mg + 2 HCl -----------> MgCl2 + H2
1 mol 1 mol
24 g 22.4 L = 22400 mL
? 80 mL
? = 24 g of Mg x ( 80 mL / 22400 mL)
= 0.086 g of Mg
Therefore,
0.086 grams of Mg is needed to produce 80.0 mL of hydrogen gas at STP.