"Molar mass 2jvv97p - PowerPoint"
Molar mass Gram atomic mass The mass, in grams, of 1 mole of an atom is equal to its atomic mass. Use the periodic table to find out 1 mol of Carbon is 12.0g 1 mol of Nickel is 58.7g Gram Molecular Mass and Gram Formula Mass = Molecular Mass Gram molar mass. The mass of one mole of a molecule is equal to the sum of the mass of the atoms in the molecule. Gram formula mass. The mass of one mole of an ionic compound is equal to the sum of the mass of the atoms in the representative formula The term Molar Mass can be used to refer to the mass of 1 Mol of any element or compound Lets practice! Question 12 p. 150 Question 13 p. 151 Question 14 p.153 Mole – Mass conversion The Molar Mass can be used as a conversion factor to convert grams of a substance into moles of that substance Lets work that through… Lets imagine we have 7.20 moles of the compound dinitrogen trioxide. How much does that weigh? First, lets work out the molecular mass of one mole of dinitrogen trioxide (N2O3) 2 mol N x 14.0 g N/1 mol N = 28.0g N 3 mol O x 16.0 g O/1 mol O = 48g O 1 mol of N2O3 = 28.0 + 48.0 = 76.0 g N2O3 Our conversion factor is: 1 mol N2O3 = 76.0g of N2O3 Or 1 mol N2O3 / 76g N2O3 Or 76 g N2O3 / 1 mol N2O3 Known = 7.60 mol N2O3 unknown = mass Conversion mole -> mass Conversion factor = 76 g N2O3 / 1 mol N2O3 7.20 mol N2O3 x 76 g N2O3 / 1 mol N2O3 = 547.2 = 5.47 x 102 g N2O3 Lets practice more! Question 18 a, b, f Question 19 a, c, g The volume of a mole of gas Standard Temperature and Pressure (STP) = 0°C and 1 atm At STP the volume of 1 mole of any gas is 22.4L This can be used as a conversion factor! Lets practice Questions 20-21 p.158 Question 23 p.159 Gas density Density is the amount of mass in a given volume. The density of gases is measured in g/L The density can be used as a conversion factor to calculate the molar mass of a gas. If you know the mass of 1L, you can calculate the mass of 22.4L easily Using gas density Imagine you know that the density of a compound containing carbon and oxygen is 1.96 g/L at STP. Is the gas CO or CO2? The volume of both gases at STP is 22.4. The molar mass must be: 22.4L of gas x 1.96g = 43.9g of unknown gas 1L The molar mass of CO is 12.0g C +16.0g O = 28.0g The molar mass of CO2 is 12.0g C + 16.0g O = 44.0g Therefore the gas must be CO2 Give Question 23 on p.159 a try! Converting between units using moles… Ultimate practice! Questions 24-27 p.161 Question 48-52 p.171