A sample of 2.0×1010 atoms that decay by alpha emission has a half-life of 100 minmin. How many alpha particles are emitted between t=50mint=50min and t=200mint=200min ?

The formation of a solid, also known as a is an indication of a chemical change. precipitate particulate particle powder

20 pts ‼️ an unmanned spacecraft travels to mars. mars has a lower strength of gravity than earth. where in the image is the spacecraft’s weight the greatest?

What is a substance? a. a physical property of matter b. a chemical property of matter c. an element or compound that cannot be physically separated d. characteristics used to tell the difference between mixtures