2na + 2h2o → 2naoh + h2 during a laboratory experiment, a certain quantity of sodium metal reacted with water to produce sodium hydroxide and hydrogen gas. what was the initial quantity of sodium metal used if 8.40 liters of h2 gas were produced at stp?

Answer : The initial quantity of sodium metal used is 17.25 grams.

Solution : Given,

Volume of gas = 8.40 L

Molar mass of Na metal = 23 g/mole

The Net balanced chemical reaction is,

At STP,  22.4 L of volume is occupied by 1 mole of gas

so,  8.40 L of volume is occupied by = = 0.375 moles of gas

Now from the above reaction, we conclude that

1 mole of gas produced by the 2 moles of Na metal

0.375 moles of gas produced = of Na metal

The quantity of Na metal used = Moles of Na metal × Molar mass of Na metal = 0.75 moles × 23 g/mole = 17.25 grams

Therefore, the initial quantity of sodium metal used is 17.25 grams.

radioactive decay occurs in unstable atomic nuclei – that is, ones that don't have enough binding energy to hold

the nucleus together due to an excess of either protons or neutrons.