1. How many moles of water are produced when 2 moles of hydrogen gas react with excess oxygen gas?

The balanced chemical equation for the reaction is:

2H2 + O2 -> 2H2O

From the equation, we can see that 2 moles of hydrogen gas react to produce 2 moles of water. Therefore, when 2 moles of hydrogen gas react, 2 moles of water are produced.

1. If 25 grams of methane (CH4) react with excess oxygen gas, what mass of carbon dioxide (CO2) will be produced?

The balanced chemical equation for the reaction is:

CH4 + 2O2 -> CO2 + 2H2O

From the equation, we can see that 1 mole of methane reacts to produce 1 mole of carbon dioxide. The molar mass of methane (CH4) is 16 g/mol, and the molar mass of carbon dioxide (CO2) is 44 g/mol.

First, we need to calculate the number of moles of methane:

Moles of CH4 = Mass of CH4 / Molar mass of CH4 Moles of CH4 = 25 g / 16 g/mol Moles of CH4 = 1.5625 mol

Since the stoichiometry of the reaction is 1:1 between methane and carbon dioxide, the number of moles of carbon dioxide produced will also be 1.5625 mol.

Now, we can calculate the mass of carbon dioxide produced:

Mass of CO2 = Moles of CO2 * Molar mass of CO2 Mass of CO2 = 1.5625 mol * 44 g/mol Mass of CO2 = 68.75 g

Therefore, 68.75 grams of carbon dioxide will be produced.

1. If the theoretical yield of a reaction is 50 grams and the actual yield is 40 grams, what is the percentage yield?

Percentage yield = (Actual yield / Theoretical yield) * 100 Percentage yield = (40 g / 50 g) * 100 Percentage yield = 80%

The percentage yield of the reaction is 80%.

1. Calculate the atom economy of a reaction if the molar mass of the desired product is 100 g/mol and the molar mass of the reactant is 200 g/mol.

Atom economy = (Molar mass of desired product / Molar mass of reactant) * 100 Atom economy = (100 g/mol / 200 g/mol) * 100 Atom economy = 50%

The atom economy of the reaction is 50%.