National Evaluation Series™ Profile: Chemistry (821)
Content Domain III: Matter and Its Interactions: Substances, Mixtures, and Solutions
Competencies:
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Descriptive Statements:
- Solve problems related to molecular mass and formula mass.
- Solve problems related to percent composition of substances.
- Determine empirical and molecular formulas.
- Apply knowledge of the use of science and engineering practices in exploring and understanding content related to Objective 0008, such as asking questions and defining problems, developing and using models, planning and safely conducting investigations, analyzing and interpreting data, using mathematics and computational thinking, constructing explanations and designing solutions, engaging in argument from evidence, and communicating and evaluating data and conclusions.
Sample Item:
Use the table below to answer the question that follows.
| Element |
Percent of Compound |
| C |
39.9%39 point 9 percent |
| H |
6.7%6 point 7 percent |
| O |
53.4%53 point 4 percent |
The table shows the percent composition by mass of a compound. Based on the data, what is the empirical formula of the compound?
- CHOC H O
- CH2OC H 2 O
- C2H2O2C sub 2 H sub 2 O sub 2
- CH3COOHC H sub 3 C O O H
Correct Response and Explanation (Show Correct ResponseHide Correct Response)
Correct Response: B.
Descriptive Statements:
- Solve problems related to solution concentrations.
- Demonstrate a qualitative and quantitative understanding of the colligative properties of solutions (e.g., freezing point depression, boiling point elevation).
- Interpret solubility curves.
- Determine the hydronium ion concentration and the pH and pOHp O H for acid, base, and salt solutions.
- Solve problems related to acid-base dissociation and neutralization in aqueous solutions.
- Apply knowledge of the use of science and engineering practices in exploring and understanding content related to Objective 0009, such as asking questions and defining problems, developing and using models, planning and safely conducting investigations, analyzing and interpreting data, using mathematics and computational thinking, constructing explanations and designing solutions, engaging in argument from evidence, and communicating and evaluating data and conclusions.
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