๐ Topic Summary
Mass percent composition tells you the relative amount of each element in a compound. It's essentially the percentage by mass of each element. You calculate it by dividing the mass of the element in one mole of the compound by the molar mass of the compound, then multiplying by 100%. Understanding this helps in determining the purity of substances and characterizing new compounds.
For example, if you have a compound like water ($H_2O$), you can calculate the mass percent of hydrogen and oxygen. This knowledge is super useful in chemistry for things like stoichiometry and understanding chemical formulas. Let's dive into some practice problems to solidify this concept!
๐งช Part A: Vocabulary
Match the terms with their correct definitions:
| Term |
Definition |
| 1. Molar Mass |
A. The percentage by mass of each element in a compound. |
| 2. Mass Percent Composition |
B. The smallest repeating unit in a crystal lattice. |
| 3. Empirical Formula |
C. The sum of the atomic masses of all atoms in a molecule. |
| 4. Stoichiometry |
D. The quantitative relationship between reactants and products in a chemical reaction. |
| 5. Unit Cell |
E. The simplest whole number ratio of atoms in a compound. |
Match the following:
- ๐ 1 - C
- ๐ฌ 2 - A
- ๐ก 3 - E
- ๐ 4 - D
- โ๏ธ 5 - B
โ๏ธ Part B: Fill in the Blanks
Complete the following paragraph with the correct words:
To calculate the mass percent composition, you need to know the ______ ______ of the element in the compound and the ______ ______ of the entire compound. Divide the mass of the element by the ______ of the compound, and then multiply by ______. This gives you the percentage of that element in the compound.
- โ๏ธ Molar Mass
- ๐งช Mass
- ๐งฎ 100%
๐ค Part C: Critical Thinking
Explain how knowing the mass percent composition of a fertilizer could be useful in agriculture.
