Please help me with Chem?!?

Question

Assume that 3.09 x 106 kJ are needed to heat a swimming pool. If this energy is derived from the combustion of methane (CH4) at standard conditions (25 oC and 1 atm) what volume in liters of methane must be burned?


The heat of combustion of methane is 889.967 kJ/mol. The density of methane is 0.0680 kg/m3

Answer 1

We are told the total amount of heat energy needed ( = 3.09 E6 kJ), which is derived from the combustion of methane.
We are also told the heat of combustion of methane is 889.967 kJ/mol.
In order to find the number of moles of methane required, simply divide the total heat needed by the amount of heat provided by 1 mole of methane.

Moles of methane = 3.09 E6 kJ / 889.967 kJ/mol
Moles methane = 3472 moles of CH4.

We know (or can look up) the molar mass of methane to be 16.05 grams per mol.
So 3472 moles of methane will have a mass of 55.73 kg.

The question tells us the density of methane is 0.0680 kg/m^3. However, I think this value is incorrect. I think you accidentally typed an extra zero in when writing the question. The actual density of methane is probably closer to 0.680 kg/m^3.

Density = mass / volume
Volume = mass / density

Volume = (55.73 kg) / (0.680 kg/m^3)
Volume = 82 m^3

1 cubic meter equals 1000 Liters.
So the volume of the methane would be: (82 m^3) * (1000 L / m^3) = 82000 Liters.

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Alternative method below:
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1 mole of an ideal gas, under standard conditions, has a volume of 24.4 Liters (at STP: 22.4 Liters).

If we assume that methane to be an ideal gas, to find the volume of methane needed all we need to do is multiply the moles of methane by the volume of methane per mole.

Volume = 3472 moles * 24.4 Liters per mol
Volume = 84717 Liters of methane.

Answer 2

Teh answer is starightforward with not much twists in it. But let me try to get this is straight to you.
First you have to find the number of moles of Methane required to heat that swimming pool. Since it is been said that it takes 3.09 * 106 kj and combustion energy from 1 mole of Methane is 889.967 kj. SO you can find the number of moles required which would be 0.368 (the number of moles seems to be too small, check wheather that is it 3.09 * 10^6 or just 3.09 * 106) and then you know that formula of number of moles =(mass of the substance in grams)/(Molecular mass of methane). You know the Molecular mass of methane is 12+4 (C+4H) =16 (approx, check peiodic table for those values) and then density=mass/volume.
and mass is density * volume. ANd then so final formula looks like
number of moles = denisty * Volume/ Molecular mass
you know everything in the above equatiuon except volume and if you keep your units consistent. you would be able to find the answer which I found to be as 86.6 m 3. I hope I was clear in explaing. E mail me back if you need some more clarrification.

Answer 3

So you know the amount of mols of methane you need. You get this by dividing 3.09 x 106 kJ by 889.967 kJ/mol. This will give you a value in mols, call this value 1. Get the molar mass of methane (approx. 16g/mol), and find the mass of methane by multiplying value 1 by the molar mass (16). Now you have mass in grams of methane you need, convert to Kg by dividing by 1000. No use the density to get volume. Volume = mass/density

Answer 4

Let methane be called M

3.09 x 10^6 kJ x 1molM/890kJ x 22.4LM/1molM = 7.78 x 10^4LM

The heat needed is given. The first factor comes from heat of combustuion of M. I use 890, because there are only three significant figures in the heat. The kJ cancel, leaving moles M. The second factor comes from the molar volume of an ideal gas. The moles cancel, leaving liters of M

Answer 5

What level of chem is this, It seems like it is in the organic or physical range. Try this as a stoichiometry problem The answer is 76.1L If you email me [e-mail] I will email you the work i did. It took me a good 20 minutes but i hope it did it right. See if it is and if so then email me with the subject Yahoo! Answers. ( CH4) Problem. Mr Jefferey is right. I wish i was smart. BMD are Dumb.

Answer 6

a million.0 Potassium is extremely electropositive element with low ionization power. This property makes the outer valance electrons ejection fairly undemanding with electric powered voltage. As you recognize electric powered impulses are using bypass of electrons 2.0 4 moles of Al reacts with 3 moles O2 giving Aluminum oxide. this suggests that 8 moles of Al desire six moles of O2 3.0 team III era iv, probably the element is Ga and the Oxide is Ga2O3 4.0 1s2 2s2 2p6 3s13Px1