States of Matter and Energy: Changes, Specific Latent Heat and Calculations

The video tutorial explains the changes of state in substances, focusing on water. It covers how thermal energy affects these changes, such as melting, freezing, boiling, and condensing, all occurring at fixed temperatures. The concept of sublimation is also introduced. The tutorial emphasizes the conservation of mass and constant temperature during state changes. It explains specific latent heat, including fusion and vaporization, and provides examples of calculations using the formula E = mL to determine energy and mass changes.

What happens to water when it is heated from below 0 degrees Celsius to 0 degrees Celsius?

• It melts into liquid water.

• It turns into steam.

• It sublimates into gas.

• It remains as ice.

Which process involves a solid changing directly into a gas?

• Melting

• Sublimation

• Freezing

• Condensation

What remains constant during a change of state?

• Volume

• Temperature

• Density

• Pressure

What does the specific latent heat of a substance represent?

• The energy needed to decrease the volume of a substance.

• The energy needed to increase the pressure of a substance.

• The energy needed to change the state of 1 kg of a substance without temperature change.

• The energy needed to change the temperature of a substance.

What is the formula used to calculate the energy required for a change of state?

• E = mv^2

• E = mgh

• E = mc^2

• E = mL

How much energy is required to melt 200 grams of ice at 0 degrees Celsius, given the specific latent heat of fusion of water is 336,000 J/kg?

• 134,400 J

• 67,200 J

• 168,000 J

• 33,600 J

If 400,000 joules of energy is absorbed by water at its boiling point, how much mass is converted to steam, given the specific latent heat of vaporization is 2,300,000 J/kg?

• 0.300 kg

• 0.250 kg

• 0.200 kg

• 0.174 kg