You start with 500g of a radioactive substance. You end with 62.5g. The half life of this substance is 33 seconds. How much time has passed?

In the 1800s, one of the statements in john dalton's atomic theory was that atoms are indivisible. later experimental evidence led to the discovery of subatomic particles such as neutrons, electrons, and protons. what happened to the indivisible atom part of dalton's atomic theory, and why?

Read the claim. breakfast is an important meal. it jump starts the body’s process of using calories to break down food. appetite can decrease with age, but going too long without eating causes metabolism to slow down. current research shows that incorporating legumes such as lentils and chickpeas into meals boosts metabolism for twenty-four hours. who might benefit from this claim? people who have a fast metabolism stores that sell exercise equipment people who take vitamin supplements grocery stores that sell legumes

Isopropyl alcohol, (ch3)2choh, is a common solvent. determine the percent by mass of hydrogen in isopropyl alcohol. a) 6.71% h b) 13.4% h c) 25.0% h d) 53.3% h