Question

Consider the following reaction: 2Na + 2HCI-+ 2NaCl +H2 How many mols of hydrogen gas (H2) can be produced if you begin with 9 .4 grams of each reactant? Record your answer in scientific notation, using 3 significant figures. Preview

> 4.7H2

Answer 1

Mass of Na = 9.4 g, Atomic mass of Na = 23 g/mol

Number of moles of Na = mass of Na in gram Atomic mass of Na = 9.4 g / 23 g/mol = 0.4087 mol

Mass of HCl = 9.4 g, Molar mass of HCl = 36.5 g/mol

Number of moles of HCl = 9.4 g / 36.5 g/mol = 0.2575 mol

From reaction, 2.0 mol of HCl reacts with 2.0 mol of Na produces 1.0 mol of H2 so 0.2575 mol of HCl will react with 0.2575 mol of Na will produce 0.2575 mol /2 = 0.12875 mol of H2.

Number of moles of H2 gas produced = 0.12875 mol = 1.2875 * 10^-1 mol ~ 1.287 * 10^-1 mol