How many molecules do you have?
Well how much mass in a mol?
3*12 + 7*1 + 16 + 1 = 60 grams for 6.022*10^23 molecules
so
we have
6.022*10^23 * 85.9/60
= 8.62*10^23 molecules
each of those molecules has 3 carbon atoms
3*8.62*10^23 = 25.9 *10^23
=2.59 * 10^24 carbon atoms
Rubbing alcohol often contains propanol, C3H7OH. Suppose you have an 85.9 g sample.
a) How many carbon atoms are in the sample?
b) How many hydrogen atoms are in the sample?
c) How many oxygen atoms are in the sample?
For a, I have tried dividing 85.9 by the total mass, 60.09502, which gave me 1.429409069.After this, I multiplied by Avagadro's constant, 6.02 x 10^23, which gave me the total atoms in propanol. However, I am not sure how to find the atoms in each individual element.
3 answers
Why would you multiply that number by 3?
Look at the formula of C3H7OH. For every molecule of C3H7OH, you have 3 C atoms. Multiply by 8 to find the number of H atoms and multiply by 1 for find O atoms.
5 answers