How many carbon atoms are there in 4.56 grams of ethanol (CH3CH2OH)?
First we have to find out how many moles of ethanol there are in 4.56 grams. The molecular mass of ethanol is 46. That means there is 1 mole (a number) of ethanol atoms in 46 grams. Now since there are 4.56 grams we have to find out how many moles of ethanol that is so do 4.56 / 46 = 0.099130435 moles of ethanol Now a mole is a special number (its called avogadro’s number, read about it on wikipedia to find out what’s the significance of it), kind of like a dozen. Similar to a dozen is 12. a mole is the number 6.022 x 10^23 Now just multiply 0.099130435 x 6.022 x 10^23 to find out how many moles of ethanol there are.