CALCULATE THE MAXIMUM VOLUME OF C02 GAS AT?

Question

250 degrees celcius and one atmosphere pressure which could be obtained by burning 240grams of graphite carbon. HINT: A dm^3 of CO2 gas has a mass of 1.81 grams of 25 degrees celcius and one atm pressure.

help needed pls..asap

Answer 1

C & O2 --> CO2

12 grams of carbon --> 44 grams CO2

240 grams Carbon @ 44g CO2 / 12 g C = 880 grams of CO2 will be produced

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the hint appears to have an intent to catch one off guard, it looks like they want to see if we will incorrectly say :

if 1.81 g of CO2 occupies 1 dm3 @ 25 C , then at 10 times the temp it will occupy 18.1 dm3.  yep, but that would only be correct if the kelvin temp went up ten fold.

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so inorder to use the old stand by equations, we need moles of CO2, which we will find using molar mass:

880 grams CO2 @ 44 g.mole = 20 moles of CO2 are produced

now at 250 Celsius = 523 Kelvin), we use

PV=nRT

(1 atm) (V) = 20 moles (0.08206 atm-dm3/mol-K) (523K)

V = 858.35 dm3

your answer (3 sig figs) :  858 dm3  ,... (aka 858 litres)

your answer (2 sig figs) :  860 dm3  ,... (aka 860 litres)

your problem is a 2 sig fig problem , unless the "240 grams & 250 C"

are 240. grams & 250. C

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does this answer seem possible? ... well the molar volume of a gas @ STP is 22.4 l/mol ,  so expect 20 moles to be about 448 litres,,,,

if it hadn't been for the fact that the temperature has almost doubled in Kelvin from STP's 273 K to this temp of 523K,... which wouuld make the 448 litres be expected to almost double also ... & that's what it did