Unit 6: Thermochemistry

If you enthalpy is negative, what type of process it is and where would the heat go in the chemical equation?

• endothermic, reactant

• endothermic, product

• exothermic, reactant

• exothermic, product

Which of the letters (A-D) represents the potential energy of the products?

• A
• B
• C
• D

Which of the letters (A-D) represents the potential energy of the reactants?

• A
• B
• C
• D

Which of the letters (A-D) represents activation energy?

• A
• B
• C
• D

Consider the reaction: 2 H₂O + energy --> 2H₂ + O₂

• exothermic, releasing energy
• exothermic, absorbing energy
• endothermic, absorbing energy
• endothermic, releasing energy

The minimum amount of energy needed to start a reaction is called the?

• surface energy
• activation energy
• concentration
• catalyst

How much heat does an aluminum block absorb if 10.00 grams is heated from 25.0^oC to 50.0^oC? *Specific heat of aluminum is 0.900 J/g^oC

• 450 J

• -450 J

• 225 J

• -225 J

A 24.0 gram sample of copper was heated from 25.0^oC to 500.0^oC, 4378 J of heat were absorbed, what is the specific heat of copper?

• 0.384 J/g°C

• 49909200 J/g°C

• 2.60 J/g°C

• 8.77 J/g°C

The temperature of an unknown piece of metal with a mass of 30.00 g changes from 25.0°C to 35.0°C when the metal absorbs 350.0 J of energy. What is the specific heat of the metal?

• 1.17 J/g°C

• -1.17 J/g°C

• 0.857 J/g°C

• -0.857 J/g°C

A sample of iron receives 50 J of heat energy that raises the temperature of the iron 25.0°C. If iron has a specific heat of 0.10 J/g°C, what is the mass of the iron sample?

• 25g

• 30g

• 20g

• 50g