How many grams of hydrogen are needed to produce 30.0 grams of water?
Paras B’s answers are correct. However, if you need to know how to get the answers, I suggest using dimensional analysis. I don’t know if it will show up correctly on here. To do this problem you need the formula as Para B listed and information from a periodic table. Formula: 2H2 + O2 => 2H2O Weights from periodic table: H = 1g/mol O = 16g/mol Weight of substances: H2 = 2g/mol O2 = 32g/mol H2O = 18g/mol The first problem, you need to understand from the formula is that to form 2 moles of water (H2O) you need 2 moles of hydrogen (H2): 2 H2O to 2 H2 (or 1 to 1 if you prefer). Start out with what you have and end up with what you need. In the equations, mol = moles 30.0g H2O x 1mol H2O / 18.0g H2O x 2mol H2 / 2mol H2O x 2g H2 / 1mol H2 = 3.33g H2 For the second problem using the same formula you need to understand that 1 mole of oxygen (O2) will react with 2 moles of hydrogen (H2). 1 O2 to 2H2 2.50g O2 x 1 mol O2 / 32.0g O2 x 2 mol H2 / 1 mol O2 x 2.0g H2 / 1 mol H2 = 3.125 g H2 Hopfully
