Introducing the Percent Composition Worksheet 2 Answer Key, an invaluable resource for students and educators alike. This comprehensive guide unlocks the intricacies of percent composition and empirical formula calculations, providing a step-by-step approach to mastering these fundamental chemistry concepts.
Delve into the world of chemical composition, where you’ll discover the secrets of determining the mass percent of each element in a compound, calculating empirical formulas, and solving practice problems with expert guidance.
Percent Composition Worksheet 2 Answer Key
Introduction to Percent Composition Worksheet 2
A percent composition worksheet is a tool used to determine the elemental composition of a compound by calculating the mass percentage of each element present. The percent composition of a compound is the percentage by mass of each element in the compound.
The empirical formula of a compound is a simplified representation of its elemental composition, indicating the relative proportions of the elements present in the compound. Completing a percent composition worksheet involves several steps, including calculating the mass of each element in the compound, determining the mass percentage of each element, and using the mass percentages to calculate the empirical formula.
Determining the Percent Composition of a Compound, Percent composition worksheet 2 answer key
To calculate the mass percent of each element in a compound, divide the mass of each element by the total mass of the compound and multiply by 100%. The mass of each element can be determined by multiplying the number of moles of the element by its molar mass.
The molar mass of an element is the mass of one mole of the element and can be found in a periodic table.
Calculating the Empirical Formula from Percent Composition
The empirical formula of a compound can be calculated from its percent composition by converting the mass percentages to mole percentages and then dividing the mole percentages by the smallest mole percentage. The resulting ratios are the subscripts in the empirical formula.
The subscripts in the empirical formula represent the relative proportions of the elements in the compound.
Practice Problems and Answer Key
Practice Problems:
| Compound | Percent Composition |
|---|---|
| NaCl | 39.34% Na, 60.66% Cl |
| H2O | 11.19% H, 88.81% O |
| C6H12O6 | 40.00% C, 6.67% H, 53.33% O |
Answer Key:
| Compound | Empirical Formula | Explanation |
|---|---|---|
| NaCl | NaCl | The mass percentages of Na and Cl are 39.34% and 60.66%, respectively. Converting to mole percentages, we get 65.58% Na and 34.42% Cl. Dividing by the smallest mole percentage (34.42%), we get a ratio of 1.904 for Na and 1.000 for Cl. Rounding to the nearest whole number gives us an empirical formula of NaCl. |
| H2O | H2O | The mass percentages of H and O are 11.19% and 88.81%, respectively. Converting to mole percentages, we get 99.98% H and 0.02% O. Dividing by the smallest mole percentage (0.02%), we get a ratio of 49.99 for H and 1.000 for O. Rounding to the nearest whole number gives us an empirical formula of H2O. |
| C6H12O6 | C6H12O6 | The mass percentages of C, H, and O are 40.00%, 6.67%, and 53.33%, respectively. Converting to mole percentages, we get 66.67% C, 13.33% H, and 20.00% O. Dividing by the smallest mole percentage (13.33%), we get a ratio of 5.000 for C, 1.000 for H, and 1.500 for O. Rounding to the nearest whole number gives us an empirical formula of C6H12O6. |
Common Queries
What is percent composition?
Percent composition is the percentage by mass of each element present in a compound.
How do I calculate the empirical formula of a compound?
To calculate the empirical formula, divide the mass percent of each element by its atomic mass and simplify the resulting ratios to the smallest whole numbers.
