Question

1.) Define standard temperature and pressure(STP). What is the value of the molar volume of any ideal gas at STP?

2.) What type of reaction is used to determine the yield of hydrogen gas in this experiment? Explain choice.

3.) How many grams of hydrogen can be expected from complete reaction of 1.0 g of Mg? Show work!

Answer 1

Dear Student,

1) Standard temperature and pressure (STP) is defined as exactly 100 kPa of pressure (0.986 atm) and 273 K (0°C).

The molar volume is the volume of 1 mol of a gas. At STP, the molar volume of a gas can be easily determined by using the ideal gas law:

All the units cancel except for L, the unit of volume. So

V = 22.4 L

any gas at STP has a volume of 22.4 L per mole of gas; that is, the molar volume at STP is 22.4 L/mol

2)It is a single replacement reaction where Mg displaces the hydrogen to form hydrogen gas and Magnesiumchloride, a salt.

Magnesium reacts with hydrochloric acid according to the equation:

Mg(s) + 2 HCl(aq) --> MgCl ₂(aq) + H ₂(g)

3)we need to find the number of moles of H₂ produced.

Then we can use the ideal gas law, with the given temperature and pressure, to determine the volume of gas produced.

the number of moles of H₂ is: (1g Mg)*(1mol Mg/24.305 g of Mg)*(1 mol H2/1mol Mg)*(2.02g H2/1 mol H2)

=2.02*24.305=0.083 g H2

Thanks & Bes Wishes