Atomic Masses 0.0 / 5 ? ChemistryAtomic massesASOCR Created by: racheonCreated on: 28-01-14 20:08 What do we use to compare masses of different atoms? Relative mass. 1 of 20 What has been chosen as the measurement of relative mass? The carbon-12 isotope. 2 of 20 What unit is used to measure atomic masses? Unified atomic mass. 3 of 20 How heavy is 1u? 1.6605 x 10^-27kg. 4 of 20 What is the mass of a carbon-12 atom? 12u. 5 of 20 What is 1/12th of a carbon-12 atom? 1u. 6 of 20 Define relative isotopic mass. The mass of an atom of an isotope compared with 1/12 of the mass of an atom of carbon-12. 7 of 20 Are all atoms in an isotope identical? Yes. 8 of 20 For an isotope, what is the relative atomic mass the same as? The mass number. 9 of 20 What have we neglected when talking about relative masses? Electrons' mass. 10 of 20 What do the masses of a proton and neutron equal? 1u. 11 of 20 Define relative atomic mass. The weighted mean mass of an atom of an element compared with 1/12 of the mass of an atom of carbon-12. 12 of 20 Define weighted mean mass. The contribution made by each isotope to the overall mass of an element. 13 of 20 What does the contribution of an isotope depend on? (2) The percentage of the isotope and the relative mass of the isotope. 14 of 20 Define relative molecular mass. The weighted mean mass of a molecule compared with 1/12 of the mass of an atom of carbon-12. 15 of 20 What is relative molecular mass used for? It's used to work out simple molecules. 16 of 20 How do you work out a relative molecular mass? By adding together the relative atomic masses of each atom. 17 of 20 Define relative formula mass. The weighted mean mass of a formula unit compared with 1/12 of the mass of an atom of carbon-12. 18 of 20 What is relative formula mass used to work out? (2) Giant structures and covalent compounds. 19 of 20 How do you work out a relative formula mass? By adding together the relative atomic masses of each atom. 20 of 20
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