Difference between revisions of "Relative Formula Mass"
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The '''relative formula mass''' ('''M<sub>r</sub>''') of a [[molecule]] is the [[mass]] of one [[mole]] of [[molecule]]s. | The '''relative formula mass''' ('''M<sub>r</sub>''') of a [[molecule]] is the [[mass]] of one [[mole]] of [[molecule]]s. | ||
| − | NB One [[mole]] is [[ | + | NB One [[mole]] is [[Avogadro Constant|6.02x10<sup>23</sup>]] [[molecule]]s. |
===About Relative Formula Mass=== | ===About Relative Formula Mass=== | ||
Revision as of 11:44, 29 October 2019
Contents
Key Stage 4
Meaning
The relative formula mass (Mr) of a molecule is the mass of one mole of molecules.
NB One mole is 6.02x1023 molecules.
About Relative Formula Mass
- The relative formula mass is used to find the mass of a molecule needed to perform a complete reaction with another chemical.
Calculating Relative Formula Mass
- Relative formula mass can be calculated from the chemical formula of the molecule and the relative atomic mass of the elements.
| Find the relative formula mass of O2. | Find the relative formula mass of CO2 | Find the relative formula mass of C6H12O6 |
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Relative Atomic Mass of Oxygen = 16g Mr of O2 = 16x2 Mr = 32g |
Relative Atomic Mass of Carbon = 12g Relative Atomic Mass of Oxygen = 16g Mr of CO2 = 12x1 + 16x2 Mr = 44g |
Relative Atomic Mass of Carbon = 12g Relative Atomic Mass of Hydrogen = 1g Relative Atomic Mass of Oxygen = 16g Mr of C6H12O6 = 12x6 + 1x12 + 16x6 Mr = 180g |