What volume of hydrogen gas is evolved from a reaction between 0.52 g of Na and water? This gas is collected at 20 C and 745mmHg

The volume of hydrogen gas that evolved is calculated as follows

by use of ideal gas equation

that is PV = nRT

P=745 mm hg

V = ?

R (gas constant) = 62.36 L. mm hg/mol. k

T = 20 + 273 = 293 k

n=number of moles which is calculated as follows

find the moles of Na used

= 0.52/23=0.023 moles

write the reacting equation

2Na + 2H2O = 2NaOH + H2

by use of reacting ratio between Na : H2 which is 2:1 therefore the mole of H2 = 0.023/2 = 0.0115 moles

by making the volume the subject of the formula

v=nRT/P

V = (0.0115 x 62.36 x 293) / 745 = 0.283 L