Chemistry Midterm 1-3

While a sample of liquid is freezing, its thermal energy

• increases

• decreases

• remains the same

• is transferred into phase energy

During region B the thermal energy is

• increasing

• decreasing

• the same

• zero

During region C the thermal energy is

• increasing

• decreasing

• the same

• zero

A sample of water in a pan is brought to a boil. Which of the following is true when boiling occurs?

• The temperature of the boiling water gradually increases.

• The liquid water immediately flashes into gaseous water.

• The temperature of the boiling water remains constant.

• The liquid water begins to break down into hydrogen and oxygen gases.

What is the purpose of using energy bar charts in the given situations?

• To calculate the exact amount of energy in a system

• To represent the ways energy is stored and flows in or out of a system

• To measure the temperature of a system

• To determine the speed of energy transfer

What happens to the thermal energy (Eth) of the coffee as it cools?

• It increases

• It decreases

• It remains the same

• It fluctuates

What does "Eth" represent in the energy bar charts?

• Electrical energy

• Thermal energy

• Chemical energy

• Nuclear energy

During the heating process, which phases are present at the same time?

• Liquid only

• Solid only

• Liquid and gas

• Gas only

What is the phase of water at 0°C during the cooling process?

• Liquid

• Solid

• Liquid and solid

• Gas

What is the phase of water at 30°C in the heating scenario before boiling?

• Liquid

• Solid

• Gas

• Liquid and gas