A sample of CaCO3 has been weighed in at 6.3 g. How many moles of calcium carbonate are present?
The first thing to think of here is what does a mole actually mean?Using the equation: Moles = Mass (g) / Molar Mass we can first find out what the molar mass of CaCO3 is.TO THE PERIODIC TABLE!1) List the individual elemental molar masses. E.g Ca = 40 C= 12 O = 162) So now we can work out what CaCO3's molar mass is = 40 + 12 + (3x16) = 40+12+48 = 100So one mole = 100g of CaCO33) Back to the equation Moles = Mass (g) / Molar Mass Moles = 6.3g (as in the question) / 100g = 0.063 moles.NB . It is important to give units (in this case 'moles') to our results.
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