Moles/Avagadro's 4.0 / 5 based on 2 ratings ? ChemistryCalculationsASOCR Created by: EmW99Created on: 20-10-16 15:00 What is a mole? The amount of substance that contains as many particles as there are in 12g of carbon-12 1 of 12 What is Avagadro's constant? 6.02 x 10 to the 23 - the amount of particles in 12g of carbon-12 2 of 12 How many moles are there in 46g of Sodium? 46/23 (the molar mass) = 2 moles 3 of 12 How do you calculate the number of moles? The mass of the substance (in grams) divided by the molar mass 4 of 12 How do you calculate the mass? The number of moles x the molar mass 5 of 12 Calculate the mass of 5 moles of methane Mr = 12+1+1+1+1=16. Mass = moles x Mr therefore 16x5 = 80g 6 of 12 How do you calculate the number of atoms in a substance? Avagadro's constant x the number of moles 7 of 12 Calculate the number of moles in 2 tonnes of CaCO3 Mr of CaCO3 = 100.1 . Moles = 2000000 divided by 100.1 = 19980 moles 8 of 12 What is empirical formula? The simplest whole number ratio of atoms of each element in a compound. 9 of 12 Find the empirical forumla of an oxide of potassium when you have 100g of potassium and 16g of oxygen 100 divided by 39.1 = 2.5 16 divided by 16 = 1 2.5/1 = 2.5 2.5x2 = 5 1x2=2 Empirical formula= K5O2 10 of 12 What is the molecular formula? The actual number of atoms of each element in a molecule 11 of 12 If the empirical formula of a substance is KNO3, and the Mr is 505.5, what is the molecular formula? Mr of KNO3 = 101.1. 505.5 divided by 101.1 = 5 so the molecular formula is K5N5O15 12 of 12
Comments
No comments have yet been made