You started with 64 g of a radioactive substance. If you have 4.0 g of that substance left, then how many half-lives have elapsed?

a. 2

b. 3

c. 4

d. 5

What does the force of gravity on an object depend on A: Molecules B: The objects mass C: compounds D: charged particles

Sodium atom Sodium has an atomic number of 11. Which atom would form an ionic bond with a sodium atom? Select one: a. Helium atom b. chloride atom c. Carbon atom d. oxygen atom

Which of the following is not a physical property of matter?

The amplitude of a wave is most directly related to what wave characteristic? Crest length Frequency Wavelength Wave height

6 Li + N2 - -> 2 Li3N How much N2 is needed to make 1.34 moles of Li3N?

How many atoms of gold (Au) are present in a sample of 2.5 mol Au? A. 1.5 * 1024 atoms Au B. 1.5 * 1023 atoms Au C. 4.2 * 1024 atoms Au D. 4.2 * 1023 atoms Au

what might cause the goldfish population to drop if the temperature moves out of its normal range? Name three things

Why must a chemistry experiments performed in a well ventilated room?

What kind of chemical bond does salt have?

How does phosphorus enter the human body?