![]() (1 atom x 23 grams/mole Na) + (1 atom x 35.5 grams/mole Cl) = 58.5 grams/mole NaClĢ. ![]() If we write this as a calculation, it looks like this: If we have a chemical compound like NaCl, the molar mass will be equal to the molar mass of one atom of sodium plus the molar mass of one atom of chlorine. Molar masses of chemical compounds are equal to the sums of the molar masses of all the atoms in one molecule of that compound. To do this, we need to remember a few rules.ġ. How can I find the molar mass of a chemical compound?įor any chemical compound that's not an element, we need to find the molar mass from the chemical formula. Still, aside from the exceptions above, all elements have the same molar mass as the atomic masses on the periodic table. phosphorus is normally found in clumps of four atoms, P 4, and sulfur is found in clumps of eight atoms, or S 8. That each molecule of the element has two atoms of that element stuck together.Īs a result, the formula of hydrogen is H 2, nitrogen is N 2, etc. ![]() In the case of hydrogen, nitrogen, oxygen,įluorine, chlorine, bromine, and iodine, the element is diatomic, meaning In some cases, the element is usually found in a differentįorm than just one unbonded atom. ![]() So, in our example, carbon has a molar mass of 12.01 grams per mole. For example, if you want to find the molar mass of carbon, you would find the atomic mass of carbon on the periodic table, and this is equal to the molar mass in grams per mole. The molar mass of elements is found by looking at the atomic mass of the element on the periodic table. How can I find the molar mass of an element? It is also sometimes called: Molecular Mass, Molecular Weight, Formula Mass, or Formula Weight. One atomic mass unit (u) is equal to 1/12 the mass of one atom of carbon-12. Thus, the quantity of substance n in moles is equal to the mass m in grams divided by the molar mass M in g/mol.Molar mass is the mass (in atomic mass units) of one mole of a of a substance. To convert the mass in grams back to the quantity of substance in moles, we simply need to reverse the formula above. You can then convert grams back to moles to check the yield of the reaction. For example, once you have carried out a reaction, you will weigh your product to find out how many grams have been produced. You’ll need a grams to moles formula to find the moles of a substance you have. You can also use our mole calculator to find the quantity of a substance. So, the mass of 2 moles of sodium chloride is 116.88 grams. Two moles of table salt, NaCl, would be twice this amount: The molar mass of sodium chloride is 58.44 g/mol, which is the sum of the atomic masses of 1 mole of sodium (Na, 22.99 g/mol) and 1 mole of chlorine (Cl, 35.45 g/mol). Thus the mass m of substance in grams is equal to the quantity n in moles multiplied by the molar mass M of the substance in g/mol.įor example, let’s calculate the mass of 2 moles of table salt, sodium chloride or NaCl. The formula used to convert moles to grams is: However, the calculator above will automatically calculate the molar mass for you. You can use a molar mass calculator for this calculation if you don’t have a reference handy. You can either use the molar mass of the entire substance, or you can calculate the molar mass of the substance by adding together the atomic masses of each element that makes up that substance. Molar mass, represented in g/mol, will be needed along with the formula below to convert moles to grams or vice versa. Because every substance is composed of different atomic elements, the atomic mass of each element in a compound or molecule is added together to determine its molar mass. The first step in the conversion is to find the molar mass of the compound. Grams are used to measure out the reactants and to check the yield of the products in a reaction.Īt this point, you might be wondering how to convert moles, which are used in chemical formulas, to grams, which is how much of each compound you’ll need to carry out the reaction in a laboratory. Moles are normally used in chemical formulas to represent the relative amount of each substance in the formula – in other words, how many moles of each reactant are needed to make a certain number of moles of product. Moles count the number of atoms or molecules in a sample, while grams represent the weight of the sample. Because that’s such a large number, it’s almost always represented using scientific notation. One mole is equal to 6.02214076 × 10 23 elementary units of matter, such as atoms or molecules. A gram is an SI unit of measurement for mass equal to 1/1,000 of a kilogram, and the mole is the SI base unit used to represent the quantity of a substance. Grams and moles are both units used in chemistry to measure matter in different ways.
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