How many moles of Calcium (Ca) atoms are in 77.4 grams of Ca?
For calcium, we see on the periodic table that the mass of calcium is 40.078 grams. This is for 1 mole of calcium atoms. From there, we take the 77.4 grams in the original question, divide by 40.078 grams and we get moles of Calcium which is 1.93 moles. With 1.93 moles, we need to calculate atoms. A mole contains 6.022 x 10^23 atoms, so we multiply them together. For your information, the 6.022 x 10^23 is known as Avogadro’s number. The number of atoms comes out to be 1.16 x 10^24. For gold, which is Au, we take the molar mass of gold, 196.97 grams/mole and multiply it by the 15.3 moles to get 3013.64 grams. For the copper, just as calcium, we find moles of copper from the 3.14 g by dividing by the molar mass (63.546 g/mole) = .049 moles. then multiply by Avogadro’s number (6.022 x 10^23) = 2.95 x 10^22. The final one can be tricky, but first we calculate the mass of C2H2. 2 carbons @ 12.011 g = 24.022. 2 hydrogens @ 1.008 g = 2.016 g. Added together, C2H2 is 26.038 g/mole. We only hav
