Chemistry Lesson 57

The density of solid carbon dioxide is 1.56 g/mL and the density of carbon dioxide gas at STP is 0.00198 g/mL. What is the volume of gas produced when 10 mL of solid carbon dioxide sublimes?

7.88 L

Which is not an example of a phase change?

expansion

A pine log floats on water. Which explanation best explains why this happens?

The log is less dense than water. Substances that are less dense float in substances that are denser.

For copper metal, what phase of matter is most dense?

solid

Which phase of matter is least dense?

gas

The density of solid carbon dioxide is 1.56 g/mL and the density of carbon dioxide gas at STP is 0.00198 g/mL. What is the volume of gas produced when 100 mL of solid carbon dioxide sublimes?

78.8 L

What phase change occurs when dew forms?

condensation

What happens to the volume and density of a gas as the gas is heated at constant pressure?

Volume increases and density decreases.

When you put dry ice, CO₂(s), in a plastic bag, the bag puffs up. Which explanation best explains what happens to cause the bag to puff up?

The CO₂ molecules spread apart from one another and bounce around inside the bag.

When you boil water, H₂O(l), it turns into steam, H₂O(g). Which explanation best explains what happens the water molecules when liquid water becomes steam?

The H₂O molecules fill up the space in the room.

What happens to the volume and density of a gas as the gas is cooled at constant pressure?

Volume decreases and density increases.