What mass of H2 gas would be formed when 2.45 g Zn reacts with excess acetic acid? Zn (s) + 2 HC2H3O2 (aq) ------> H2 (g) + Zn (C2H3O2)2(aq)
how many moles of Zn in 2.45g?
You will get that many moles of H2, according to the equation.
so, how many grams is that?
To calculate the mass of H2 gas formed, we need to use stoichiometry. The balanced equation shows that 1 mole of Zn reacts with 2 moles of acetic acid to produce 1 mole of H2 gas. From the molar masses of Zn and H2, we can convert the mass of Zn to moles and then convert moles of Zn to moles of H2 using the stoichiometric coefficients.
1. Calculate the molar mass of Zn:
The atomic mass of Zn from the periodic table is approximately 65.38 g/mol.
2. Convert the mass of Zn to moles:
The equation provides the molar ratio between Zn and H2, so we need to convert the given mass of Zn to moles. Use the equation:
moles of Zn = mass of Zn / molar mass of Zn
Given:
mass of Zn = 2.45 g
molar mass of Zn = 65.38 g/mol
moles of Zn = 2.45 g / 65.38 g/mol
3. Determine the moles of H2 gas formed:
Use the stoichiometric ratio between Zn and H2 from the balanced equation to calculate the moles of H2 produced. In this case, since the reaction goes to completion and Zn is in excess, all the acetic acid reacts and the stoichiometric ratio remains the same.
From the balanced equation, the stoichiometric ratio is 1:1 between Zn and H2:
moles of H2 = moles of Zn
4. Convert moles of H2 gas to grams:
Finally, convert the calculated moles of H2 gas to grams using the molar mass of H2:
mass of H2 = moles of H2 x molar mass of H2
The molar mass of hydrogen (H2) is approximately 2 g/mol.
mass of H2 = moles of H2 x 2 g/mol
Now you can substitute the values and calculate the mass of H2 produced.