In a certain compound of copper and oxygen, CuxOy, we find that a sample weighing 0.9294 g contains 0.3435 g of Cu.
How many moles of Cu are there in the sample?
DO NOT USE EXPONENTIAL NOTATION
Moles of Cu = Mass of Cu x (1 mol Cu / 63.546 g Cu) = 0.3435 g Cu x (1 mol Cu / 63.546 g Cu) = 0.005406 mol
If one can find the ratio of the number of moles of the elements in a compound to one another, one can find the formula of the compound. In a certain compound of copper and oxygen, CuxOy, we find that a sample weighing 0.8885 g contains 0.2212 g of Cu.
How many grams of O are in the sample?
DO NOT USE EXPONENTIAL NOTATION
Grams of O = 0.8885 g - 0.2212 g Cu = 0.6673 g
If one can find the ratio of the number of moles of the elements in a compound to one another, one can find the formula of the compound. In a certain compound of copper and oxygen, CuxOy, we find that a sample weighing 0.7470 g contains 0.6904 g of Cu.
How many mole of O are there in the sample?
DO NOT USE EXPONENTIAL NOTATION
Mass of O = 0.7470 g - 0.6904 g Cu = 0.0566 g
Moles of O = Mass of O x (1 mol O / 16.00 g O) = 0.0566 g O x (1 mol O / 16.00 g O) = 0.00354 mol
A compound containing two elements (X, atomic mass = 32.00 g/mol and Y, atomic mass = 32.00 g/mol) is found to contain 1.2000 grams of X and 0.6000 grams of Y. What is the mole ratio of Y:X? The answer may or may not be a whole number. Express the answer to three decimal places.
Moles of X = Mass / Molar Mass = 1.2000 g X / 32.00 g/mol = 0.03750 mol
Moles of Y = Mass / Molar Mass = 0.6000 g X / 32.00 g/mol = 0.01875 mol
Mole Ration of Y:X = (Moles of Y / Moles of X) = (0.01875 mol / 0.03750 mol) = 0.500
A carbohydrate is found to contain 0.2000 grams of C and 0.4500 grams of water. What is the mole ratio of C:water? The answer may or may not be a whole number. Express the answer to three decimal places.
Moles of C = 0.2000 g C / 12.011 g C = 0.01665 mol
Moles of H2O = 0.4500 g H2O / 18.016 g H2O = 0.02498 mol
Mole Ration of C:H2O = 0.01665 mol / 0.02498 mol = 0.667