How many grams of hydrogen are produced from the decomposition of 100 grams of hydrogen peroxide?
H2O2(l) → H2(g) + O2(g)
a. 100 g H2
b. 50 g H2
c. 6 g H2
d. 1 g H2
To find out how many grams of hydrogen are produced from the decomposition of hydrogen peroxide, we need to use stoichiometry and the molar mass of hydrogen.
First, we need to determine the molar mass of hydrogen peroxide (H2O2). The molar mass of H2O2 can be calculated by adding up the atomic masses of the elements in one molecule of H2O2. The atomic mass of hydrogen (H) is approximately 1 g/mol, and oxygen (O) is approximately 16 g/mol.
So, molar mass of H2O2 = 2(1 g/mol) + 2(16 g/mol) = 2 g/mol + 32 g/mol = 34 g/mol.
According to the balanced chemical equation, 2 moles of hydrogen gas (H2) are produced for every 1 mole of hydrogen peroxide (H2O2) that decomposes.
Now, let's calculate the number of moles of H2O2 in 100 grams using the molar mass:
Number of moles of H2O2 = mass of H2O2 / molar mass of H2O2 = 100 g / 34 g/mol ≈ 2.94 mol.
According to the stoichiometry of the reaction, for every 1 mole of H2O2, we get 2 moles of H2. Therefore, the number of moles of H2 gas produced is:
Number of moles of H2 = 2.94 mol H2O2 x (2 mol H2 / 1 mol H2O2) = 5.88 mol H2.
Finally, we can calculate the mass of H2 gas using the molar mass of hydrogen (H):
Mass of H2 = number of moles of H2 x molar mass of H2 = 5.88 mol H2 x 2 g/mol H2 = 11.76 g H2.
So, the correct answer is (b) 50 g H2.