Question 126703
Chemistry answer:<br />

Propane has 3 carbon atoms (meth=1, eth=2, prop=3, but=4, pent=5, hex=6, hep=7, oct=8, ...) and it is an alkane (ends with -ane). The number of hydrogen atoms in an alkane is twice the number of carbons plus two. 2*3+2=6+2=8. So 3 carbons and 8 hydrogen.<br />

(This is definitely correct, so your question is wrong, the chemical is not propane)<br />

Maths answer:<br />

The chemical is made up of 26 atoms, and they are either carbon or hydrogen. So c+h=26. The number is hydrogen atoms is six less than three times the carbon, so h=3c-6. Substituting this into the first equation gives c+(3c-6) = 32, which rearranges to 4c=32, and then c=8. Using the second equation h=3c-6, h=3*8-6=24-6=18. So c=8, h=18.<br />

(This is in-fact an alkane, because h=2*c+2, and it is called octane.)<br />

English answer:

"a molecule of propane has 26 atoms."<br />

"how many atoms does it contain"<br />

26! (although, like I said it definitely is not propane.