Question

If 0.071g of magnesium is used in this experiment, what volume of dry H2 gas would theoretically be produced if it is measured at 20°C and 785 mm Hg?

a) 0.224 L
b) 0.448 L
c) 0.672 L
d) 0.896 L

Answer 1

Option (A), To determine the volume of dry H2 gas produced, we need to use the ideal gas law equation PV = nRT. Convert the mass of magnesium to moles using the molar mass, convert the temperature to Kelvin, convert the pressure to atmospheres, and substitute the values into the equation to solve for V.

Step-by-step explanation:

To determine the volume of dry H2 gas produced, we need to use the ideal gas law equation:

PV = nRT

1. Convert the mass of magnesium to moles using the molar mass: 24.305 g/mol.
2. Convert the temperature to Kelvin by adding 273.15: 20+273.15 = 293.15 K.
3. Convert the pressure to atmospheres: 785 mmHg * (1 atm/760 mmHg) = 1.034 atm.
4. Substitute the values into the equation: (1.034 atm) * V = (0.071 g / 24.305 g/mol) * (0.0821 L*atm/mol*K) * (293.15 K).
5. Solve for V: V = (0.071 g / 24.305 g/mol) * (0.0821 L*atm/mol*K) * (293.15 K) / 1.034 atm.

Calculating the answer gives us V = 0.224 L.