what is the relative mass of methane?
920990
methane: CH4\n\nMr;\ncarbon 12\nhydrogen 1\n\nMr of methane= 1*carbon+4*hydogen\n=12+4\n=16\n\ntherefore one mole of methane weighs 16 grams\n\n4 g of methane= 4/16\n=0.25 moles\n------------------------------...\n\none mole of any gas occupies 24 dm3 at r.t.p\n\nmoles of oxygen in 7 dm3= 7/24\n=0.292 moles
179135
Methane has a structure of four hydrogens attached to a carbon
784060
Mass (kg) 5.688e+26 \n\nAsking or saying the mass of a planet has more meaning.  You can't really talk about the weight of a planet.
728848
Yes and no. Methane is generated constantly from decomposing organic matter,but not in enough quantity for humans to use. Nature cannot keep up with our demand! :-)=
187568
You can come up with a molecular weight of air - use the percentages of the different molecules comprising air and the molecular weight of the components.  The answer is around 29 g/mol (I think).
664728
One mole of *anything* = 6.023x10^23 units of that item.\n\nSo if you have 6.10x10^24 molecules of ethane, that's:\n\n6.10x10^24/6.023x10^23 = 10.13 moles.\n\nMultiply 10.13 moles by the molecular weight of ethane to get your answer.
216195
"The moon's mass is (7.35 x 10 22 kg), about 1/81 of the Earth's mass."  http://www.enchantedlearning.com/subjects/astronomy/moon/
912377
A has a higher percent carbon than B.\n\nThe molecular mass of A is 194 g/mol and it contains 96 g/mol of carbon.  96 g/mol carbon /194 g/mol molecule A = 0.495 = 49.5% carbon\n\nThe molecular mass of B is 342 g/mol and it contains 144 g/mol of carbon.  144 g/mol carbon/342 g/mol molecule B = 0.421 = 42.1% carbon.
116849
Propane and methane are both simple hydrocarbons (CH4 and C3H8) that can be produced from crude oil or other petroleum products by fractional distillation, cracking, etc...methane is the simpler of the two (CH4) and is a byproduct of many digestive and degradative processes.  Landfill gases (and cow farts, to be crude) both contain high percentages of methane and both have been collected and burned for energy.  Propane is more commonly used as a fuel for rural areas, for gas grills, etc.  They differ from diesel and gasoline by being  pure hydrocarbons instead of a mixture of hydrocarbons, and they are also smaller molecules, gases at room temperature instead of liquids, etc., etc..
1010084
Propane  = C3H8. The molar mass is\n(3 x 12 + 8 x 1) gram = 44 gram.\nYou give 44.1 g. That a little bit better.\n\nThe volume of the cylinder is\nAh = pi r2 h = 3.14 x (0.050 m)^2 x 1.30 = 0.212 m3.\n\nBefore: pV = nRT\n1.4×10^6 Pa x 0.212 m3 = n x 8.31 J/(mol x K) x (273 + 23)K\nSo n(begin) = 119 mol.\n\nAfter: pV = nRT\n2.4×10^5 Pa x 0.212 m3 = n x 8.31 J/(mol x K) x (273 + 23)K\nSo n(end) = 20 mol.\n\nUsed is (119 - 20) mol propane, being 99 x 44.1 gram = 4.4 kg
1087435
well, first start with the molecular weight of gold (197 by definition), then divide it by the number of atoms in a mole (6.2*10^23), which gives you a mass of 3.18*10^-22 g.
641455
Least C6H6 with like .5 moles\nThen 1 mole of CH4 and the 44 g CO2 both have same\nAnd then the 2 mole Br2
552992
ch4 for both.\nOne carbon atom and 4 hydrogen atoms. Simple!
609337
The atomic mass of a chemical element is the mass of an atom at rest, most often expressed in unified atomic mass units. The atomic mass is often synonymous with relative atomic mass, average atomic mass and atomic weight; however, it is subtly different in that it can either be the abundance-weighted average of isotope masses of an element or the mass of a single isotope.\n\nThe relative atomic mass (also known as atomic weight and average atomic mass) is the average of the atomic masses of all the chemical element's isotopes as found in a particular environment, weighted by isotopic abundance. Periodic tables usually list these with reference to the local environment of Earth's crust and atmosphere. An uncertainty in parenthesis is often included. For artificial elements the nucleon count of the most stable isotope is listed in brackets as the atomic mass
808665
You're right. The empirical formula is (CH3)x. The molar mass of (CH3)x is:\n\n(12 + 3*1)x = 15x\n\nSo:\n\n15x = 30, x = 2\n\nAnd the molecular formula is:\n\nC2H6    (CH3-CH3 : ethane)
918968
(See answer to very similar question at the second source listed below)\n\nAssuming ideal gas behavior, we have that the molar density (moles per unit volume) of a gas is given by:\n\nmolar density = n/V = P/(R*T)\n\nwhere R is the gas constant = 62.363 (liter*torr)/(mol*K) -see source\nP is the pressure\nT is the absolute temperature\n\nTo convert from molar density to mass density (mass per unit volume) we simply multiply by the molecular mass of the material in question. In this case, the molecular mass of propane is 44.1. \n\nPutting all this together, and plugging in values:\n\nmass density = (44.1 gm/mol)*(874 torr)/((62.363 liter*torr/mol*K)* (273.15+95)K)\n\nmass density = 1.679 gm/liter = 1.679e-3 gm/cm^3
897929
convert 995.0 g CH4 into moles and then multiply that answer with 882kJ/mole -- make sure your units cancel