PROBLEM 4.2.12 4.2. 12. Determine the number of moles of the compound and determine the number of moles of each type of atom in each of the following: (a) 2.12 g of potassium bromide, KBr. (b) 0.1488 g of phosphoric acid, H 3 PO 4. (c) 23 kg of calcium carbonate, CaCO 3. (d) 78.452 g of aluminum sulfate, Al 2 (SO 4) 3.
One mole of a compound contains Avogadro's number (6.022 x 1023) of molecules (molecular compound) or formula units (ionic compound). The molar mass of a compound tells you the mass of 1 mole of that substance. In other words, it tells you the number of grams per mole of a compound. The units for molar mass are, therefore, grams/mole. Is RMM the same as molar mass? The molecular mass and relative molecular mass are distinct from but related to the molar mass. The molar mass is defined as the mass of a given substance divided by the amount of a substance and is expressed in g/mol. What is RAM and RMM in chemistry? 1. RAM is a mass of an atom, relative to the mass of C-12. First calculate the molar mass of the unknown gas; Determine the identity of the gas by comparing the calculated molar mass to molar masses of known gases. Solution: A Since we are at STP, we can use the following equation to calculate molar mass: \[MM = \rho \cdot 22.4 L/mol\] \[MM = \rm 1.783 g/L \cdot 22.4 L/mol\] \[MM = \rm 39.9 g/mol\] . 398 307 300 106 212 360 76 334 7