Home Early recorded sounds & wax cylinders Cylinder music shop An Edison commemorative 2nd page Note to early recordings collectors Cylinder of the month Links to related topics What's new Tinfoil resource center Cylinders of the month archive CJ's comics Copyright (C) (P) 1996-2015 Glenn Sage, Portland, Oregon.
1) That looks right. 2) Step 1: Moles=Mass/Mr, so it's 144/72= 2mol. Step 2: Stoichiometry means the ratio of oxygen to pentane is 1:8 so moles of oxygen is moles of pentane times 8. 2*8=16mol of oxygen. Step 3: 16= 9.6*10^24. 3) The ratio of oxygen to carbon in CO2 is 1:2. so it's 192/3 = 64.
The mole is related to the mass of an element in the following way: one mole of carbon-12 atoms has 6.02214179 Ã 1023 atoms and a mass of 12 grams. In comparison, one mole of oxygen consists, by definition, of the same number of atoms as carbon-12, but it has a mass of 16 grams. Oxygen, therefore, has a greater mass than carbon. This reasoning also can be applied to molecular or formula weights.