Ap Chem Unit 6

When pellets of NaOH are added to a flask of water, it is observed that the temperature of the water increases as the pellets dissolve. Which of the following claims about the observed dissolution of NaOH in water is most accurate?

• It is an endothermic process because heat energy is absorbed by the water as the NaOH dissolves in it.

• It is an endothermic process because heat energy is released by the water as the NaOH dissolves in it.

• It is an exothermic process because heat energy is absorbed by the water as the NaOH dissolves in it.

• It is an exothermic process because heat energy is released by the water as the NaOH dissolves in it.

Tags

NGSS.HS-PS1-4

If 1 Calorie = 4.18 kJ, how many kJ of energy can be released by an apple containing 125 Cal?

• 0.0334 kJ

• 29.9 kJ

• 523 kJ

• 5.23 × 10⁵ kJ

Tags

NGSS.HS-PS3-1

If heat is released by a chemical system, an equal amount of heat will be

• absorbed by the surroundings

• absorbed by the universe

• released by the surroundings

• released by the universe

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-4

How many joules of heat are required to raise the temperature of 225 g of aluminum from 20°C to 100°C? (specific heat of aluminum = 0.21 J/g°C)

• 3780 J

• 0.59 J

• 85 J

• 58 J

Tags

NGSS.HS-PS3-4

The specific heat capacity of a substance is the heat required to warm

• The substance by 1 degree Celsius

• 1 gram of water by one degree Fahrenheit

• 1 gram of the substance by one degree Celsius

• An equal weight of water by one degree Fahrenheit

Based on the values in the table, what is the change in enthalpy for the reaction NaOH(aq) + HCl(aq) → NaCl(aq) + H₂O(l)?

• - 56.7 kJ/mol

• 229.1 kJ/mol

• -1329.5 kJ/mol

• -693.1 kJ/mol

Tags

NGSS.HS-PS1-4

How does heat flow?

• Always from cold to warm
• Always from warm to cold
• Both warm to cold & cold to warm
• It depends on the temperature

Tags

NGSS.HS-PS3-4

The amount of energy required to raise the temperature 1ºC for every gram is called____?

• Thermal Energy

• Specific Heat

• Temperature

• Kinetic Energy

The energy level diagram for a reaction is shown.

Which statement is correct?

• X is the energy change of the reaction.

• Y is the activation energy of the reaction.

• The energy change of the reaction is larger than the activation energy of the reaction.

• The reaction is exothermic.

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1

The graph above is from which type of reaction?

• Endothermic reaction

• Exothermic Reaction

Tags

NGSS.HS-PS1-4