Anyone know how to do this multiple choice chem question? (1 Viewer)

[MathsN00b]

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[huuh]

Is it D?

 

[MathsN00b]

How did you get D? I'm still lacking with molar heat combustion stuff.

 

[huuh]

To find the mass of fuel burnt, you'll need the amount of moles i.e. n = g/molar mass
To find the moles, given molar heat of combustion (2800kJ), divide the heat generated by 2800.
Then multiply the moles by molar mass to get the mass.

 

[MathsN00b]

Is the formula for pentan-1-ol C5H11OH?

 

[MathsN00b]

I ended up with the answer 3.7853... I think I did something wrong

 

[huuh]

Yeah penta-1-ol is C5H11OH
108/2800 = 0.03857 moles
0.03857 x (60 + 12 x 1.008 + 16) = 3.397 or 3.40 3 sig. fig.

 

[gandalfbrah]

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