Questions and Answers
Which of the following phase changes is endothermic?
Which one of the following phase changes would be exothermic?
What phase change is represented by the transition from A to C?
sublimation
Which of the following phases does a sample of water exist in at its triple point?
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Which best explains why the meniscus of mercury in a glass tube is convex?
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What is surface tension?
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What is a saturated solution?
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What is an unsaturated solution?
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What is a supersaturated solution?
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What is an Arrhenius acid?
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What is a Bronsted-Lowry acid?
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What is a Bronsted-Lowry base?
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Acid + base ->
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Which of the following can be classified as a strong base?
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What are the products of a strong acid/strong base reaction?
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What is oxidation in terms of electron transfer?
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What is reduction?
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What does the oxidation number (ON) represent for atoms in pure elements?
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What is a nonelectrolyte?
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What is a strong electrolyte?
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Which compound can be classified as a weak electrolyte?
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What does endothermic mean?
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What does exothermic mean?
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1 dietary cal =
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How many calories are in fats per gram?
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How many kilocalories are in carbohydrates per gram?
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How many kilocalories are in protein per gram?
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What is the oxidation number of hydrogen?
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What is the oxidation number of oxygen?
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What do oxidizing agents do?
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What do reducing agents do?
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What is sodium oxidation number?
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4.184 j =
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100 j per
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4.185 kj =
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1000 cal =
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When molecules absorb heat, there is an increase in
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What does the First Law of Thermodynamics tell us?
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An exothermic reaction causes the surroundings to
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DeltaH =
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Study Notes
Phase Changes
- Endothermic Phase Change: Sublimation is an endothermic process where a solid transitions directly to a gas, requiring energy input.
- Exothermic Phase Change: Condensation is an exothermic process in which gas transitions to liquid, releasing energy as molecules become closer together.
- Triple Point of Water: The triple point is defined as the temperature and pressure where solid, liquid, and gas phases coexist.
Surface Tension
- Convex Meniscus of Mercury: High surface tension in mercury creates a convex meniscus as mercury molecules are more attracted to each other than to the glass surface.
- Surface Tension Definition: The energy required to separate molecules at the surface of a liquid.
Solutions
- Saturated Solution: Contains the maximum concentration of solute possible at a specific temperature.
- Unsaturated Solution: Contains less solute than the maximum at a given temperature.
- Supersaturated Solution: Contains more solute than predicted to be soluble at a given temperature.
Acids and Bases
- Arrhenius Acid: Produces hydronium ions when dissolved in water.
- Brønsted-Lowry Acid: A substance that donates protons (H+ ions).
- Brønsted-Lowry Base: A substance that accepts protons.
Reactions
- Acid-Base Reaction Products: The reaction between an acid and a base produces water and a salt.
- Strong Bases: Examples include LiOH, NaOH, KOH, RbOH, CsOH, Ca(OH)2, Sr(OH)2, and Ba(OH)2.
- Products of Strong Acid/Strong Base Reaction: Resulting products are water and salt.
Oxidation and Reduction
- Oxidation: Involves the gain of oxygen, loss of electrons, and an increase in oxidation state.
- Reduction: Involves loss of oxygen, gain of electrons, and a decrease in oxidation state.
Oxidation Number Rules
-
General Oxidation Number (ON) Rules:
- ON is 0 for pure elements.
- ON equals the charge for monatomic ions.
- Hydrogen has an ON of +1.
- The sum of ON in a neutral molecule is 0.
Electrolytes
- Nonelectrolyte: A substance that does not form ions in aqueous solution (e.g., Cl₂).
- Strong Electrolyte: Dissociates completely in water (e.g., NH₄NO₃).
- Weak Electrolyte: Partially ionizes in water (e.g., HF).
Thermodynamics
- Endothermic Process: Heat is absorbed during the process.
- Exothermic Process: Heat is released, causing the surroundings to warm up.
- First Law of Thermodynamics: States that energy in the universe is constant.
Key Energy Concepts
-
Caloric Values:
- Fats: 9 kcal/g
- Carbohydrates: 4 kcal/g
- Proteins: 4 kcal/g
-
Conversion Factors:
- 1 dietary calorie (cal) = 1 kilocalorie (kcal)
- 4.184 joules (J) = 1 calorie (cal)
- 1000 calories (cal) = 1 kilocalorie (kcal)
Molecular Kinetics
- Heat Absorption: Leads to an increase in the kinetic energy of molecules.
- ΔH Calculation: Change in enthalpy is calculated as products minus reactants.
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Description
Test your knowledge with these flashcards focused on phase changes in chemistry. This quiz covers both endothermic and exothermic processes, emphasizing key concepts like sublimation and condensation. Ideal for students preparing for an exam.
