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Questions and Answers
Which of the following is an example of an exothermic process?
Which of the following is an example of an exothermic process?
Which letter on the PE diagram represents the energy of the activated complex?
Which letter on the PE diagram represents the energy of the activated complex?
What is the numerical value of the activation energy on the PE diagram?
What is the numerical value of the activation energy on the PE diagram?
What is the specific heat (Cs) of aluminum?
What is the specific heat (Cs) of aluminum?
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Determine the final temperature (x) when 175 grams of hot aluminum (100.0°C) is dropped into an insulated cup containing 40.0 mL of ice-cold water (0.0°C).
Determine the final temperature (x) when 175 grams of hot aluminum (100.0°C) is dropped into an insulated cup containing 40.0 mL of ice-cold water (0.0°C).
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Which of the following best describes the law of conservation of energy?
Which of the following best describes the law of conservation of energy?
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What is the symbol for the enthalpy of reaction?
What is the symbol for the enthalpy of reaction?
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Which type of reaction has a negative change in enthalpy (∆H)?
Which type of reaction has a negative change in enthalpy (∆H)?
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What is the stored energy or energy of position known as in chemistry?
What is the stored energy or energy of position known as in chemistry?
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Which of the following statements about enthalpy change is true?
Which of the following statements about enthalpy change is true?
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Study Notes
Thermodynamics and Reactions
- An exothermic process releases energy, often in the form of heat, making the surroundings warmer. Common examples include combustion and respiration.
- On a potential energy (PE) diagram, the energy of the activated complex, where reactants transition to products, is typically represented by the highest point on the curve.
- The activation energy is the minimum energy required for a reaction to occur and is indicated on the PE diagram as the vertical distance between the reactants' energy level and the peak of the activated complex.
- The specific heat (Cs) of aluminum is approximately 0.897 J/g°C, indicating how much energy is needed to raise the temperature of one gram of aluminum by one degree Celsius.
Heat Exchange in Systems
- To determine the final temperature (x) when hot aluminum is placed in water, apply the principle of conservation of energy: heat lost by aluminum = heat gained by water.
- For aluminum (mAl × Cs × ΔT) = (mass of water × Cs of water × ΔT of water), where ΔT = (final temp - initial temp).
Laws and Principles
- The law of conservation of energy states that energy cannot be created or destroyed, only transformed from one form to another. This applies to both closed and isolated systems.
- The symbol for the enthalpy of reaction is ΔH, which indicates the heat change during a chemical reaction at constant pressure.
- A negative change in enthalpy (∆H) signifies an exothermic reaction, where energy is released, making this type of reaction energetically favorable.
- In chemistry, stored energy or energy of position is referred to as potential energy, which is associated with the arrangement of particles within a system.
Enthalpy Change Insights
- Accurate statements about enthalpy change often highlight its importance in predicting the heat exchange during reactions, assisting in determining whether a reaction is favorable or requires external energy input.
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Description
Test your knowledge of exothermic and endothermic reactions with this quiz. Classify given statements as examples of either exothermic or endothermic processes. Also, answer questions related to potential energy diagrams. Ideal for chemistry students and enthusiasts.
