A scientist has 2.5 grams of radium-226. How many grams of the sample will decay in 8000 years?

Which of the following is a testable hypothesis? a. if i brush my teeth, i will get fewer cavities than if i don't brush my teeth. b. green toothpaste tastes better than blue toothpaste or red toothpaste. c. smart, careful, healthy people always brush their teeth. d. it's wrong to not brush your teeth before you have an important conversation with someone.

Solar energy is energy from the sun that is converted into thermal or energy. a. nuclear b. mechanical c. electrical d. chemical

Use the table to identify the phase and phase changes of the elements under the given conditions. write the name of the substance, phase, or phase change