C2.3 0.0 / 5 ? ChemistryCalculations, moles and yieldGCSEAQA Created by: bethhammondCreated on: 20-11-16 15:36 What is the mass of the following: Electron? Proton? Neutron? E = 0.0005, P = 1, N = 1 1 of 15 what is the mass number? The total number of protons and neutrons in the nucleus of an atom. 2 of 15 Do atoms of the same elment have the same mass number or atomic number? Atomic number - this is the number of protons (and therefore electrons). 3 of 15 What are isotopes? Atoms of the same element with different numbers of neutrons. 4 of 15 How do you work you the number of neutrons? Minus the atomic number (no of protons) from the mass number (number of protons and neutrons in the nucleus) 5 of 15 How many protons, electrons and neutrons are there in the atom flourine? E = 9, P = 9, N = 10 6 of 15 What is RAM? Relative atomic mass - Ar 7 of 15 What is a mole? The RAM of an elemnt in grams - eg a mole of sodium has a mass of 23g 8 of 15 What is RFM Relative formula mass - Mr. This is all the RAM in a substance added together to find the total of the substance/compound etc. 9 of 15 Calculate the Mr of Calcium Chloride CaCl2 (Ca = 40) + (Cl = 35.5) + (Cl = 35.5) = 111 10 of 15 How do you work out the mass of a mole of any substance? Work out the RFM and add grams at the end 11 of 15 How do we work out what percentage one element is of a compound? 1. Find the RFM 2. Divide the RAM of the substance you want to find by the RFM 3. Times by 100 + round if necessary 12 of 15 Find the percentage of carbon in CO2 1. RFM = 44 2. (RAM of carbon = 12 so..) 12/44 = 0.2727... 3. 0.273 x 100 = 27.3% 13 of 15 What is the empirical formula? Simplest ratio of the atoms or ions in a compound. e.g CH3 or H2O 14 of 15 Find the empirical formula of the compound that contains 70% iron and 30% oxygen Iron = 70/56 = 1.25, Oxygen = 30/16 = 1.875 Simplest ratio = 1.25/1.25 = 1 and 1.875/1.25 = 1.5 so Empirical formula = 1:1.5 = 2:3 so Fe2O3 15 of 15
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