Chemistry unit 2 review

Front

What is density?

Back

Density is the mass of an object divided by its volume, typically expressed in g/cm³ or g/mL.

Front

How do you calculate density?

Back

Density = Mass / Volume.

Front

What is the density of copper if its mass is 216g and volume is 24cm³?

Back

9 g/cm³.

Front

What is a compound?

Back

A compound is a substance formed when two or more elements are chemically bonded together, such as H2O.

Front

What is the half-life of an isotope?

Back

The half-life is the amount of time it takes for half of the nuclei in a sample of the isotope to decay.

Front

If an isotope has a half-life of 3 days, how much of a 100g sample remains after 6 days?

Back

25g remains after 6 days.

Front

What is the formula for calculating the remaining quantity of a substance after a certain number of half-lives?

Back

Remaining quantity = Initial quantity × (1/2)^(number of half-lives).

Front

What is the density of an object with a mass of 30g and a volume of 5mL?

Back

6 g/mL.

Front

What is the difference between an element and a compound?

Back

An element is a pure substance that cannot be broken down into simpler substances, while a compound is made up of two or more elements.

Front

What is the significance of the half-life in radioactive decay?

Back

The half-life helps determine how long it takes for a radioactive substance to decay to a certain level.