Molar Mass
What is molar mass?Molar mass is the weight of one mole (or 6.02 x 1023 molecules) of any chemical compounds. Molar masses of common chemical compounds that you might find in the chemistry laboratory can range between 18 grams/mole for compounds like water to hundreds of grams per mole for more complex chemical compounds.The lightest possible chemical that one can have under normal conditions is hydrogen gas, or H2. There is no limit to how heavy a chemical compound can be - it is not uncommon for macromolecules (large organic or bioorganic compounds such as DNA) to weigh thousands of grams per mole. |
How can I find the molar mass of an element?The molar mass of elements is found by looking at the atomic mass of the element on the periodic table. 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. So, in our example, carbon has a molar mass of 12.01 grams per mole.There are a few exceptions to this rule. In some cases, the element is usually found in a different form than just one unbonded atom. In the case of hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, and iodine, the element is diatomic, meaning that each molecule of the element has two atoms of that element stuck together. As a result, the formula of hydrogen is H2, nitrogen is N2, etc.This gets weirder for a couple of cases... phosphorus is normally found in clumps of four atoms, P4, and sulfur is found in clumps of eight atoms, or S8.Still, aside from the exceptions above, all elements have the same molar mass as the atomic masses on the periodic table. |
How can I find the molar mass of a chemical compound?For any chemical compound that's not an element, we need to find the molar mass from the chemical formula. To do this, we need to remember a few rules:1. Molar masses of chemical compounds are equal to the sums of the molar masses of all the atoms in one
How can I find the molar mass of an element?The molar mass of elements is found by looking at the atomic mass of the element on the periodic table. 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. So, in our example, carbon has a molar mass of 12.01 grams per mole.There are a few exceptions to this rule. In some cases, the element is usually found in a different form than just one unbonded atom. In the case of hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, and iodine, the element is diatomic, meaning that each molecule of the element has two atoms of that element stuck together. As a result, the formula of hydrogen is H2, nitrogen is N2, etc.This gets weirder for a couple of cases... phosphorus is normally found in clumps of four atoms, P4, and sulfur is found in clumps of eight atoms, or S8.Still, aside from the exceptions above, all elements have the same molar mass as the atomic masses on the periodic table. |
How can I find the molar mass of a chemical compound?For any chemical compound that's not an element, we need to find the molar mass from the chemical formula. To do this, we need to remember a few rules:1. Molar masses of chemical compounds are equal to the sums of the molar masses of all the atoms in one