<p>Based on this equation: 2AL + 3CuCl2 -> 2AlCl3 + Cu ... how many grams of copper(II) chloride dihydrate would be required to react completely with 1.20g of aluminum metal?</p><p>You are given a chemical equation. The coefficients in front of chemicals in this equation indicate the relative molar amounts needed for this reaction.</p><p>The term molar above is in bold and highlighted because it is VERY important. You can NOT compare the masses of differing compounds. If you are doing any type of comparison, always always always convert to mols.</p><p>That being said, you can now think about what you need to do to solve the problem</p><p>What you have: 1. Relative molar amounts of each compound from the chemical equation 2. Mass of Aluminum metal</p><p> First determine the number of mol of Al you have. In order to do this, you need the molar mass of Aluminum. This may be found on the periodic table</p><p>MAl = 26.98 g/mol (molar mass of Al)</p><p>Perform dimensional analysis:</p><p> Find number of mol CuCl2 needed by using mol to mol ratio from chemical equation</p><p>The two coefficients highlighted above are the ones of interest. The 2 in front of the Al and 3 in front</p><p> of CuCl2 indicate that that for every 2 mol of Al, 3 mol of CuCl2 are needed. So, the number of mol of </p><p>CuCl2 needed is</p><p> Now the only thing left to do is to find the mass. Don’t be tricked here, they don’t ask for the number of grams of Copper (II) Chloride, but the number of grams of Copper (II) Chloride dihydrate </p><p>(CuCl2*2H2O) . This basically just means that you add the molar mass of water to the molar mass of </p><p>CuCl2 twice for the calculation below. I’ll show you how to set it up, but I’ll leave it to you to solve. Wikipedia on CuCl2: (http://en.wikipedia.org/wiki/Copper%28II%29_chloride) </p><p>Contains molar mass information.</p>