americium-241 has a half-life of 430 years. how much of a 10.0g sample of americium-241 remains after 1720 years?

A solution of a specific vitamin has λmax = 273 nm and a concentration of 8.33 * 10-7 m. the absorbance of the solution at 273 nm is a = 0.180. what is the molar absorptivity of the vitamin at 273 nm? (sample pathlength = 1.00 cm)

A student is doing chemistry lab using strong acid and starts eating

Which of the following describes an important role scientists have in society?

What is the maximum number of electrons in the first electron shell, closest to the nucleus? a. 1 b. 2 c. 4 d. 8

Arsenic-80 alpha decay

An engineering team is conducting a trial launch of a new rocket. Which part of the engineering process is the team in?

What is a physical property of copper

Which of the following occurs when the ocean's salinity increases? a. density increases. b. density decreases. c. temperature increases. d. temperature decreases.

What name is given to the bond between water molecules?

Which of the following statements is false? The mean free path of a molecule depends on the size of the molecule.