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Questions and Answers
What is often referred to as the source of life?
What is often referred to as the source of life?
Water
What is the name of the chemical bond that joins atoms of elements together in a compound?
What is the name of the chemical bond that joins atoms of elements together in a compound?
Chemical Bonds
What is another name for the chemical formula of a compound?
What is another name for the chemical formula of a compound?
Molecular Formula
What is the chemical formula of glucose?
What is the chemical formula of glucose?
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What is the percent composition of an element in a compound?
What is the percent composition of an element in a compound?
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What kind of data is used to determine the percent composition of a compound?
What kind of data is used to determine the percent composition of a compound?
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What is the equation for calculating percent composition from experimental data?
What is the equation for calculating percent composition from experimental data?
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What is the mass of 1 mole of the element carbon?
What is the mass of 1 mole of the element carbon?
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What is the equation for calculating percent composition using molar mass?
What is the equation for calculating percent composition using molar mass?
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What are abbreviations that are used to represent chemical elements in written form?
What are abbreviations that are used to represent chemical elements in written form?
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The combination of atoms in a compound has no definite proportion by mass.
The combination of atoms in a compound has no definite proportion by mass.
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Chemists can determine the composition of a compound based on the percentage of the elements that comprise it.
Chemists can determine the composition of a compound based on the percentage of the elements that comprise it.
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In obtaining the percent composition, the mass of the elements, as well as the compound, must be determined first.
In obtaining the percent composition, the mass of the elements, as well as the compound, must be determined first.
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The molar mass of the compound may be used to calculate its percent composition.
The molar mass of the compound may be used to calculate its percent composition.
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To determine the molar mass of a compound, multiply the molar mass of each element to its subscript in the formula then divide the results.
To determine the molar mass of a compound, multiply the molar mass of each element to its subscript in the formula then divide the results.
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What is the molar mass of sodium bicarbonate (NaHCO3)?
What is the molar mass of sodium bicarbonate (NaHCO3)?
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What is the molar mass of iron (III) oxide (Fe₂O₃)?
What is the molar mass of iron (III) oxide (Fe₂O₃)?
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What is the molar mass of C7H5N3O6?
What is the molar mass of C7H5N3O6?
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What is the molar mass of calcium phosphate (Ca3(PO4)2)?
What is the molar mass of calcium phosphate (Ca3(PO4)2)?
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What is the molar mass of urea (CO(NH2)2)?
What is the molar mass of urea (CO(NH2)2)?
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Calculate the percent composition of sodium bicarbonate (NaHCO3).
Calculate the percent composition of sodium bicarbonate (NaHCO3).
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Calculate the percent composition of iron (III) oxide (Fe₂O₃).
Calculate the percent composition of iron (III) oxide (Fe₂O₃).
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Calculate the percent composition of C7H5N3O6.
Calculate the percent composition of C7H5N3O6.
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Calculate the percent composition of calcium phosphate (Ca3(PO4)2).
Calculate the percent composition of calcium phosphate (Ca3(PO4)2).
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Calculate the percent composition of urea (CO(NH2)2).
Calculate the percent composition of urea (CO(NH2)2).
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What is the molar mass of sodium arsenate (Na₂AsO₄)?
What is the molar mass of sodium arsenate (Na₂AsO₄)?
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How can you determine the mass of the elements in a given sample of a compound using the concept of percent composition?
How can you determine the mass of the elements in a given sample of a compound using the concept of percent composition?
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Study Notes
General Chemistry 1, Unit 7, Lesson 7.1: Percent Composition
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Introduction: Water is a vital compound, a substance composed of different elements bonded together. Compounds can be simple, like water or salt, or complex, like glucose, which contain multiple elements in varying ratios. These ratios are described using chemical formulas.
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Learning Objectives: Students should be able to describe percent composition and calculate the percent composition of a given compound or molecule based on its chemical formula.
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Warm Up (Activity): Students participate in a candy-counting activity to explore the concepts of chemical formulas and percent composition in a real-world example. The activity uses different colored candies to represent elements, aiding in the understanding of the concepts.
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Calculating Percent Composition from Experimental Data: The percent composition of a compound's elements can be determined using the masses of the elements present (as measured in experiments).
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Calculating Percent Composition Using Molar Mass: The percent composition can also be calculated if the compound's molar mass and the mass of each element within the compound can determine the percent mass.
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Key Points:
- Chemical formulas indicate the type and number of atoms in a compound.
- The percent composition of elements in a compound represents the proportion of each element by mass in the compound.
- Percent composition calculations can allow us to determine the relative amounts of each element in a compound.
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Key Formulas:
- % composition = (mass of an element / mass of the compound) x 100
- % composition = (mass of each element / molar mass of the compound) x 100
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Guide Questions: Questions related to concepts of chemical formulas and percent composition.
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Explanation of Chemical Formulas: Chemists use symbols to represent elements and formulas to represent compounds. Formulas show the ratio and the types of atoms and their numerical subscripts in compounds in a straightforward and efficient method.
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Percent Composition Determination: Each element contributes to a compound's overall mass, and the proportion of each element's mass relative to the total compound mass is the percent composition.
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Examples and Practice: Detailed examples (Examples 1 & 2) demonstrate calculating mass percent in compounds given relevant data. Additional practice exercises (Try It! 1, 2 & 3) are provided.
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Tips, Key Points and Calculating Percent Composition Using Molar Mass: These sections elaborate on aspects of understanding how to calculate a compound’s percent composition and related concepts (molar mass, relevant calculations, and the rationale behind using molar masses).
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Description
In this lesson, students will learn about percent composition and how to calculate it from chemical formulas. Through interactive activities like candy counting, this unit simplifies the understanding of compounds and their elemental ratios. Engage with practical examples to solidify your grasp of this essential chemistry concept.
