Final answer:
To calculate the theoretical number of moles of hydrogen gas produced, stoichiometry is used, where the quantitative relationship between reactants and products is analyzed. The specific reaction needs to be known to carry out calculations. For example, in the reaction of zinc with hydrochloric acid, the moles of zinc react one-to-one with moles of hydrogen produced.
Step-by-step explanation:
Calculating the Theoretical Number of Moles of Hydrogen Gas Produced
To calculate the theoretical number of moles of hydrogen gas produced, we need to apply stoichiometry, the branch of chemistry looking at the quantitative relationship between reactants and products in a chemical reaction. The actual reaction that produces hydrogen gas needs to be specified to do this properly. For example, if we consider the reaction of zinc with hydrochloric acid:
Zn(s) + 2 HCl(aq) → ZnCl₂(aq) + H₂(g)
We can tell from the balanced chemical equation that one mole of Zn will produce one mole of H₂. If we begin with 5.98 grams of Zn, the number of moles of Zn can be calculated using the molar mass of Zn. Then, using stoichiometry, we can calculate the number of moles of H2 produced.
Another example is if we have a certain amount of hydrogen and nitrogen reacting to form ammonia, as shown below:
3 H₂(g) + N₂(g) → 2 NH₃(g)
From this, we understand that 4.20 moles of hydrogen will react with an excess of nitrogen to form a certain number of moles of ammonia. The mole ratio between H₂ and NH₃ is 3:2, meaning 4.20 moles of H₂ will produce 2.80 moles of NH₃.
To calculate the pressure of hydrogen gas in a storage tank, we can use the ideal gas law, which is PV=nRT. We need to know the number of moles of gas, the volume of the container, and the temperature (in Kelvin) to use this law. For instance, if we have 2520 moles of hydrogen gas at 27°C in an 180-L tank, we can calculate the pressure in bar.