Thermochemistry Basics

What is the definition of specific heat?

• The temperature at which a substance freezes

• Amount of heat required to raise the temperature of one gram of a substance by one degree Celsius

• The amount of energy released during a chemical reaction

• Amount of heat required to boil water

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NGSS.HS-PS3-4

Explain the concept of calorimetry and its application in chemistry.

• Calorimetry is used in chemistry to measure the heat of chemical reactions or physical changes.

• Calorimetry is used in chemistry to measure the pressure of chemical reactions

• Calorimetry is used in chemistry to measure the color changes in chemical reactions

• Calorimetry is used in chemistry to measure the volume of chemical reactions

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How is energy involved in chemical reactions?

• Energy is involved in the breaking and forming of chemical bonds.

• Chemical reactions release energy but do not require it

• Chemical reactions only involve physical changes, not energy

• Energy is not involved in chemical reactions

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What is the difference between endothermic and exothermic reactions?

• Endothermic reactions and exothermic reactions both release heat into the surroundings.

• Endothermic reactions and exothermic reactions both absorb heat from the surroundings.

• Endothermic reactions release heat into the surroundings, while exothermic reactions absorb heat from the surroundings.

• Endothermic reactions absorb heat from the surroundings, while exothermic reactions release heat into the surroundings.

Tags

NGSS.HS-PS3-4

Calculate the specific heat of a substance if 500 J of energy is required to raise the temperature of 100g of the substance by 10°C.

• 2 J/g°C

• 100 J/g°C

• 5 J/g°C

• 0.05 J/g°C

Why is it important to understand the energy changes in chemical reactions?

• To make the reaction more complicated

• To predict the feasibility and direction of the reaction, and to design and optimize industrial processes.

• To confuse scientists

• To waste time and resources

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Discuss the relationship between energy and chemical bonds.

• Chemical bonds store potential energy

• Chemical bonds have no effect on energy

• Chemical bonds are not related to potential energy

• Chemical bonds release kinetic energy

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Explain the concept of enthalpy and its significance in chemical reactions.

• Enthalpy is the measure of acidity in a chemical reaction.

• Enthalpy is the total energy of a system and its significance in chemical reactions is to indicate the amount of heat absorbed or released.

• Enthalpy is the amount of matter present in a chemical reaction.

• Enthalpy is the speed at which a chemical reaction occurs.

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What are the units of energy and how are they related to chemical reactions?

• Degrees Celsius (°C) or Fahrenheit (°F)

• Volts (V) or amperes (A)

• Meters (m) or kilograms (kg)

• Joules (J) or calories (cal)

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How does energy transfer occur in an open system during a chemical reaction?

• Exchange of heat and work with the surroundings

• Exchange of light with the surroundings

• Exchange of mass with the surroundings

• Exchange of sound with the surroundings