[DivineDeity]

Hello, thanks for looking at my questions.

Legend : e = exposing

Question 1:
What is the mass (in gram) of benzene (C6H6) which contains 7.74 x 10 e24 atoms of hydrogen?

First I took the atomic mass of Hydrogen (1.007) and multiplied it by 6 which gave me 6.042. Then I used the law of avogadro to divide it : 6.042 divided by 6.022045 x 10 e23, which then gave me 1.003313658 e 23, then I finally multiplied it by 77.2 to give me the answer I was looking for (7.74 x 10 e24 atoms of hydrogen).

Subsequently, I assumed since it was C6,  Carbon (12.01) would have to be multiplied by 6 to join its comrade hydrogen with an atomic mass of 72.06.

Fused they would give me 78.102 which I would then multiply by 77.2 to give me the mass of the benzene in grams = 6029.9 grams in relation to the many atoms of hydrogen.

Is this correct, what went wrong?

Question 2:

Calculate the number of hydrogen atoms (in mol) found in 27.5 mL of isopropyl (C3H8O) if the mass (volume) of  isopropyl at a certain temperature consists of 0.825 g/mL.

I'm guessing H8(8.056) divided by 6.022 x 10 e23 = 1.33761541 x10 e23 multiplied by 0.825 = 1.10365371 x 10 e 23 multiplied by 0.2750 = 3.035046496 x 10e22

But where does the room temperature come in to play?

I have absolutely no clue how to calculate this, I didn't get a formula anywhere, an example would be nice. Please and thank you.

I missed the second class due to a late night lab, and look where I am today!!

All help is appreciated, thank you

(0.2750) (27.5) divided by 0.825 = 9.166 divided by 6.022 x 10 e 23 = my gobbledegook.

[Borek]

What is the mass (in gram) of benzene (C6H6) which contains 7.74 x 10 e24 atoms of hydrogen?

No idea what and why you did  

If there is 6 hydrogen atoms per benzene molecule, and there are 7.74x10²⁴ atoms of hydrogen, how many benzene molecules do you have? How many moles of benzene it is?

Calculate the number of hydrogen atoms (in mol) found in 27.5 mL of isopropyl (C3H8O) if the mass (volume) of  isopropyl at a certain temperature consists of 0.825 g/mL.

Use volume and density to calculate mass of isopropanol.