Enthalpy and Thermochemistry Test

During an exothermic reaction, heat content in the surrounding increases because -

• all reactions release heat energy

• the reaction releases heat energy

• the reaction absorbs heat energy

• heat energy is destroyed during reactions

Why do we use foam cups as calorimeters?

• allows heat to be exchanged with the environment easily

• shields from heat loss and/or gain to the environment

• cheap

• doesn't harm the environment

Tags

NGSS.HS-PS3-4

The diagram shows what happens when zinc reacts with hydrochloric acid. Which of these best describes the energy transformation that occurs during this reaction?

• Thermal energy - kinetic energy

• Kinetic energy -potential energy

• Chemical energy - thermal energy

• Potential energy - chemical energy

Tags

NGSS.HS-PS1-4

The diagram represents two solids and the temperature of each. What occurs when the two solids are placed in contact with each other?

• Heat energy flows from solid A to solid B. Solid A decreases in temperature

• Heat energy flows from solid A to solid B. Solid A increases in temperature

• Heat energy flows from solid B to solid A. Solid B decreases in temperature.

• Heat energy flows from solid B to solid A. Solid B increases in temperature.

Tags

NGSS.HS-PS3-4

Experimental Set-up for Calories in a Chocolate Chip Cookie Students designed an experiment to determine the amount of calories in a chocolate chip cookie. A ring stand was used with a clean aluminum soda can hung from the ring that was partially filled with a known mass of water. A thermometer was placed inside the can so that it measured the temperature of the water but did not touch any part of the metal can. Once set-up was complete, an initial water temperature was taken. The cookie was then lit on fire and allowed to completely burn. A final temperature of the water was measured.

Refer to the experimental set-up for calories in a chocolate chip cookie. How does this experiment allow students to measure the calories in a cookie?

• The difference in masses before and after the cookie is burned is calculated, then converted into heat energy.

• Heat energy from the burning cookie is transferred to the water. The change in water temperature is used to calculate the heat energy from the cookie.

• Data from the amount of time for the cookie to burn and the temperature change are used to calculate the heat energy from the cookie.

• The cookie is burned until the water reaches a boiling temperature, then masses are compared to calculate the heat energy from the cookie.

Tags

NGSS.HS-PS3-4

In an endothermic reaction the system is releasing energy.

• True

• False

Tags

NGSS.HS-PS1-4

For an endothermic reaction, the heat is on the ____ side.

• reactant

• product

• either side

Tags

NGSS.HS-PS1-4

For an exothermic reaction, the heat is on the ____ side

• reactant

• product

• either side

What is thermochemistry?

• study of heat changes that occur during a chemical reaction & physical changes of state

• the study of heat and chemistry

• the study of heat

• the study of chemistry

Tags

NGSS.HS-PS1-4

NGSS.HS-PS1-5

NGSS.HS-PS3-4

When you add heat energy...

• Temperatures increase

• Molecules move slower

• Molecules move faster

• Temperatures decrease

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4