A compound has an empirical formula of C 2 HF has a molar mass of 132.06 g/mol. 200.0 g sample of an acid with a molar mass of 616.73g/mol contains 171.36 g of carbon, 18.18g of nitrogen and the rest is hydrogen. Strychine has a molar mass of 334 g/mol and percent composition of 75.42%C, 6.63%H and 8.38%N and the rest oxygen. Answer a. C 6 H 3 Like "1 dozen", "1 mole" refers to an exact number. Molar mass refers to the mass of a very specific number of molecules/atoms: 1 mole. The molar mass is the mass divided by the amount (number of individual entities such as atoms or molecules) of substance measured in moles. Now 1 mole is equal of course to Avogadro's constant $\pu{N_A}$. Figure 2.8.4: Calculation of molar mass of ionic compound (table salt, NaCl) (adopted from OpenSTAX) You can also calculate the molar mass of polyatomic ions. This is often called molecular weight or formula weight. Example: The molar mass of sulfate (SO 4-2) 1 mole S (1) (32.07) = 32.06g. 4 mole O (4) (16.00) = 64.00g. The molar mass of a compound is the mass in grams of 1 mole of that substance, a property expressed in units of grams per mole (g/mol) Because the definitions of both the mole and the formula mass are based on the same reference substance, 12 C, the molar mass of any compound is numerically equivalent to its formula weight in amu. The periodic table shows that the atomic mass (rounded to two decimal points) of Al is 26.98, so 1 mol of Al atoms has a mass of 26.98 g. According to the periodic table, 1 mol of U has a mass of 238.0 g, so the mass of 2 mol is twice that, or 476.0 g. Exercise 6.2.1 6.2. 1: Moles to Mass Conversion with Elements. The mass in grams of 1 mole of substance is its molar mass. Due to the use of the same reference substance in defining the atomic mass unit and the mole, the formula mass (amu) and molar mass (g/mol) for any substance are numerically equivalent (for example, one individual H 2 O molecule weighs approximately 18 amu and one mole of H 2 O Molar Mass (Formula Weight) The molar mass (formula weight) is the mass of 6.022x10 23) atoms or compounds (molecules or ionic formula). The terms Molar Mass and Formula Weight are synonymous. Molecular weight is also often used to describe molar mass, but formula weight is better, as not all compounds are molecules (many are ionic). These terms are functionally the same as molar mass. For example, the GAM of an element is the mass in grams of a sample containing N A atoms and is equal to the element's atomic weight expressed in grams. GFM and GMM are defined similarly. Other terms you may encounter are formula mass and molecular mass. .

is molecular weight and molar mass the same