Solution - Finding a molecular mass
Step-by-step explanation
1. Break down the molecule to its elements
The molecule C2H5OH consists of:
2 Carbon atoms
6 Hydrogen atoms
1 Oxygen atom
| Element | Symbol | # of atoms |
| Carbon | C | 2 |
| Hydrogen | H | 6 |
| Oxygen | O | 1 |
2. Identify the atomic mass of each element
The atomic mass is shown below each element on the periodic table.
C2H5OH molecules consist of:
Carbon C=12.0107 u
Hydrogen H=1.00794 u
Oxygen O=15.9994 u
| Element | Symbol | Atomic mass | # of atoms |
| Carbon | C | 12.0107 | 2 |
| Hydrogen | H | 1.00794 | 6 |
| Oxygen | O | 15.9994 | 1 |
3. Calculate the total atomic mass of each element in a molecule of C2H5OH
C2 → 2·12.0107=24.0214 u
H6 → 6·1.00794=6.04764 u
O → 1·15.9994=15.9994 u
| Element | Symbol | Atomic mass | # of atoms | Total atomic mass |
| Carbon | C | 12.0107 | 2 | 24.0214 |
| Hydrogen | H | 1.00794 | 6 | 6.04764 |
| Oxygen | O | 15.9994 | 1 | 15.9994 |
4. Calculate the mass of the molecule C2H5OH
24.0214+6.04764+15.9994=46.06844
The average molecular mass of C2H5OH is 46.06844 u.
5. Graph of molecular composition by atoms
6. Graph of molecular composition by mass
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Please leave us feedback.Why learn this
Every physical thing in the world is made up of matter. Whether it is the air we breathe, the food we eat, or the gas we use to heat our homes, almost everything that exists is made up of matter, and all matter is made up of molecules. Because of this, understanding the properties of molecules can help us better understand the concepts that explain the world around us, such as why different materials behave as they do. Molecular mass is also an important concept for anyone interested in pursuing a career in certain STEM fields.