Apiece of sodium metal reacts completely with water as follows: 2na(s) + 2h2o(l) ⟶ 2naoh(aq) + h2(g) the hydrogen gas generated is collected over water at 25.0°c. the volume of the gas is 246 ml measured at 1.00 atm. calculate the number of grams of sodium used in the reaction. (vapor pressure of water at 25°c = 0.0313 atm.)

Explanation:

1. Gather all the information in one place

M_r:   22.99

           2Na + 2H₂O ⟶ 2NaOH + H₂

T = 25.0 °C

V = 246 mL

2. Moles of H₂

To find the moles of hydrogen, we can use the Ideal Gas Law:

pV = nRT

(a) Calculate the partial pressure of the hydrogen

(b) Convert the volume to litres

V = 246 mL = 0.246 L

(c) Convert the temperature to kelvins

T = (25.0 + 273.15) K = 298.15 K

(d) Calculate the moles of hydrogen

3. Moles of Na

The molar ratio is 2 mol Na: 1 mol H₂

4. Mass of Na

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