You must first find the molar mass of the element or compound. Use the Periodic Table (see the link to the left of the answer). If the chemical is an element, just read off the Atomic Mass from the periodic table. If it is a compound, you must know the molecular formula, and then you find the total molar mass of the compound by adding up the atomic masses of each atom in the compound. The unit of the molar mass will be in grams per moles (g/mole)
Once you have the molar mass, you can easily convert from grams to moles, and also from moles to grams.
Number of moles = (# of grams) / (molar mass)
Number of grams = (# of moles) * (molar mass)
Here are a two examples:
Example 1:
How many moles are in 5 grams of O2?
The molar mass of O2 = 16.00 g/mole x 2 (for 2 atoms of oxygen) or 32.00 g/mole.
5 g of O2 / (32 g/mole) = 0.15625 moles
Example 2:
How many grams does 4 moles of NH3 weigh?
The molar mass of NH3 = 14.01 + (3 * 1.01) = 17.04 g/mole
4 moles * 17.04 g/mole = 68.16 grams Grams in a MoleIn chemistry a mole is considered to be Avogadro's number (6.02 x 1023)of molecules (or atoms) of a substance - so depending on the density of the substance, the mass of that amount of the substance could vary widely.
One mole of hydrogen, for example, would have a different mass than one mole of lead. The question compares two different measurements of a given substance, rather like asking "how heavy is a gallon?". The question becomes "A gallon of what"?
*On the other hand, the Eastern Mole (Scalopus aquaticus) a small, burrowing mammal, weighs between 54 and 99 grams at adult size.
To convert grams to moles simply multiply the molar mass by the number of moles.
II. CHANGING NUMBER OF MOLES TO MASS If we are given the number of moles of a substance, we can convert that into a mass, based on our knowledge of Molar mass. We can use the formula from the section above, and adjust it for the new unknown, which will be mass of the sample: mass of the sample
# of moles of the substance = ---------------------------
Molar mass of substance To isolate the mass of the sample, we must multiply both sides by Molar mass of a substance: mass of the sample x Molar mass of substance
# of moles of the substance x Molar mass of substance = ---------------------------
Molar mass of substance So we are left with the formula: mass of the sample = # of moles of the substance x Molar mass of the substance. Example 1. A certain laboratory procedure requires the use of 0.100 moles of magnesium. How many grams of magnesium would you mass out on the balance? Solution, from the period table we get the Molar mass of magnesium as 24.3 g. We then place that information in the formula below: mass of the sample = # of moles of the substance x Molar mass of the substance. Given: The # of moles of the substance = 0.100 mol
The Molar mass of the substance = 24.3 g/mol mass of the sample = 0.100 mol of magnesium x 24.3 g/mol
MOLES TO GRAMS
Multiply the number of moles by the molar mass of the substance.
CONVERSION FACTOR
Number of moles x Molar mass
////////////////////////// 1 mol
GRAMS TO MOLES
Divide grams by the molar mass of the substance.
CONVERSION FACTOR
Mass (g) x 1 mol
/////////// molar mass
Finding Molar Mass
Number of Atoms Element A x Atomic Mass Element A (periodic table) = mass (g)
Number of Atoms Element B x Atomic Mass Element B (periodic table) = mass (g)
.. etc.
Add the mass values found above and you have molar mass.
Ex. Ba3N2 (Barium Nitride)
3 Atoms Ba x 137.33 = 411.999g
2 Atoms N x 14.0067 = 28.0134g
Molar Mass = 439.9944 (411.999 + 28.0134)
Kilograms is a unit of mass, moles is a unit of "amount of matter", which in this case means something different. Therefore you can't do a general conversion. For a specific substance, to convert from moles to grams, you just look up the molecular mass of the substance. For example: water has a molecular mass of 18; that means that one molecule has a mass of 18 amu; and one mole has a mass of 18 grams. So, you can multiply the number of moles by 18 (in this example). To convert that to kilograms, you divide by 1000.
To convert from kilograms to moles, you proceed in the opposite direction. Look up the molecular mass; multiply kilograms by 1000 to get grams; and divide by the molecular mass to get moles.
MOLES TO MOLECULES
Multiply the number of moles by Avogadro's number (6.022 x 1023).
CONVERSION FACTOR
Moles x 6.022 x 1023 molecules
////////////// 1 mol
MOLECULES TO MOLES
Divide the number of moles by Avogadro's number.
CONVERSION FACTOR
Moles x 1 mol
/// 6.022 x 1023 molecules
It depends on the RMM (relative molecular mass) of the molecule your dealing with.
For example if you had 2 Moles of ethene (C2H4) then you would simply multiply the number of moles by the RMM, which for ethene is approximately 28 [2C=24 +4H=28]
So just multiply the RMM (28) by the number of moles(2) which gives 56g
so 2 Moles of C2H4 weighs 56g.
Gram is a measurement of mass. A mole represents a number of Avogadro Constant. The relationship between them: The mass of a mole of a substance is equivalent to the relative molecular mass in grams.
number of moles = mass of the substance/molar mass of the substance
Gram is an unit of mass and cannot be converted in a unit of volume as litre.
Mol is the expression in grams of the molar mass or atomic weight.
This is a two-step calculation. First convert grams Cs to moles Cs. Then convert moles Cs to atoms Cs.The atomic weight of cesium is 133 g/mol1. To convert grams to moles:moles Cs= 53.7 g Cs1 mol = 0.404 mol Cs133 gMultiply by moles per gram. Grams cancel out.2. To convert moles to atoms:atoms Cs = 0.404 mol Cs6.02 x 1023 atoms = 2.43E+23 atoms CsmolMultiply by atoms/mole. Moles cancel out.
The conversion factor you need for this problem is the atomic mass of arsenic.74.9 gram arsenic = 1 mole arsenicSince you want to end up in units of moles of As, this goes in the numerator (on top). You want to convert from grams As, so this goes in the denominator (on the bottom).grams As1 mole As = moles As74.9 gram As
a moles (b moles/a moles) = b moles
1 gram carbon (1 mole C/12.01 grams) = 0.08 moles carbon ===============
The conversion factor you need for this problem is the atomic mass of germanium.72.6 gram germanium = 1 mole germaniumSince you want to end up in units of moles of Ge, this goes in the numerator (on top). You want to convert from grams Ge, so this goes in the denominator (on the bottom).grams Ge1 mole Ge = moles Ge72.6 gram Ge
See the Related Questions to the left of this answer:"How do you convert from grams to moles and also from moles to grams?"
This is a two-step calculation. First convert grams Cs to moles Cs. Then convert moles Cs to atoms Cs.The atomic weight of cesium is 133 g/mol1. To convert grams to moles:moles Cs= 53.7 g Cs1 mol = 0.404 mol Cs133 gMultiply by moles per gram. Grams cancel out.2. To convert moles to atoms:atoms Cs = 0.404 mol Cs6.02 x 1023 atoms = 2.43E+23 atoms CsmolMultiply by atoms/mole. Moles cancel out.
Change it's gram weight into moles using the periodic table.
Convert grams into moles. To do so, you divide mass by the molar mass of the substance.
divide by the molecular mass, (units of gram per mol)
how many moles are in 95.0 gram of octane?
moles = mass/Mr moles = 100/(23+16+1) moles of NaOH = 2.5mol
The answer is 3 moles.
The conversion factor you need for this problem is the atomic mass of arsenic.74.9 gram arsenic = 1 mole arsenicSince you want to end up in units of moles of As, this goes in the numerator (on top). You want to convert from grams As, so this goes in the denominator (on the bottom).grams As1 mole As = moles As74.9 gram As
The answer is 0,111 moles.
a moles (b moles/a moles) = b moles
85.2 gram LiF sample is equivalent to 3,28 moles.