Difference between revisions of "Relative Formula Mass"
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No. [[Oxygen]] [[atom]]s = 2 | No. [[Oxygen]] [[atom]]s = 2 | ||
| − | + | '''M<sub>r</sub>''' of O<sub>2</sub> = 16x2 | |
| − | + | '''M<sub>r</sub>''' of O<sub>2</sub> = 32g | |
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No. [[Oxygen]] [[atom]]s = 2 | No. [[Oxygen]] [[atom]]s = 2 | ||
| − | + | '''M<sub>r</sub>''' of CO<sub>2</sub> = 12x1 + 16x2 | |
| − | + | '''M<sub>r</sub>''' of CO<sub>2</sub> = 44g | |
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No. [[Oxygen]] [[atom]]s = 6 | No. [[Oxygen]] [[atom]]s = 6 | ||
| − | + | '''M<sub>r</sub>''' of C<sub>6</sub>H<sub>12</sub>O<sub>6</sub> = 12x6 + 1x12 + 16x6 | |
| − | + | '''M<sub>r</sub>''' of C<sub>6</sub>H<sub>12</sub>O<sub>6</sub> = 180g | |
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Revision as of 19:19, 2 January 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 |
|
Relative Atomic Mass of Oxygen = 16g Mr of O2 = 16x2 Mr of O2 = 32g |
Relative Atomic Mass of Carbon = 12g Relative Atomic Mass of Oxygen = 16g Mr of CO2 = 12x1 + 16x2 Mr of CO2 = 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 of C6H12O6 = 180g |