Exploring Phase Change Diagrams and Latent Heat

The video explains phase change diagrams, a tool used to understand how substances change phases as heat is added. It covers the graph's axes, the significance of plateaus, and the concept of latent heat. The video also provides formulas for calculating energy during phase changes and demonstrates these concepts through a sample problem.

What is the primary purpose of a phase change diagram?

• To calculate the speed of a chemical reaction

• To show the chemical composition of a substance

• To illustrate the changes in temperature and phase of a substance as heat is added

• To measure the density of a substance

Tags

NGSS.MS-PS1-4

At what temperature does water boil and condense?

• 100 degrees Celsius

• 50 degrees Celsius

• 150 degrees Celsius

• 0 degrees Celsius

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

What happens to the temperature of a substance during a phase change?

• It increases

• It decreases

• It remains constant

• It fluctuates

Tags

NGSS.MS-PS1-4

What is latent heat?

• The heat lost during a chemical reaction

• The heat required to change the phase of a substance without changing its temperature

• The heat absorbed by a substance to increase its mass

• The heat required to change the temperature of a substance

Tags

NGSS.MS-PS1-4

What does the term 'latent heat of fusion' refer to?

• The energy needed to increase the temperature of a solid

• The energy needed to change a solid to a liquid or vice versa

• The energy needed to change a gas to a liquid

• The energy needed to change a liquid to a gas

Tags

NGSS.MS-PS1-4

Which formula is used to calculate the energy required for a phase change from solid to liquid?

• Q = mHv

• Q = mC

• Q = mcΔT

• Q = mHf

Tags

NGSS.MS-PS1-4

In the sample problem, what is the first step to solve the problem?

• Calculate the energy needed to boil the water

• Calculate the energy needed to melt the ice

• Calculate the energy needed to heat the liquid water

• Calculate the energy needed to heat the solid ice to its melting point

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

What is the specific heat capacity of liquid water used in the sample problem?

• 2.09 J/g°C

• 4.186 J/g°C

• 334 J/g

• 100 J/g

Tags

NGSS.MS-PS3-4

How many steps are involved in solving the sample problem provided in the video?

• Two

• Three

• Four

• Five

What is the final answer for the total thermal energy required in the sample problem?

• 4441.25 J

• 20930 J

• 67121.2 J

• 125000 J

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-3

NGSS.MS-PS3-4