Calcium has three different isotopes. One has a mass of 35 amu; another has a mass of 41 amu; and another has a mass of 40 amu. Calculate the average atomic mass of calcium.

In each case, decide if the change is a "chemical change" or a "physical change". a) A cup of household bleach changes the color of your favorite T-shirt from purple to pink. b) Water vapor in your exhaled breath condenses in the air on a cold day.

Which process will change a substance chemically? A. boiling B. melting C. burning D. evaporating

What is the significance of a standard system of measurement? A. scientists come from different cultural backrounds B. scientists from around the world need a way to share data they can all understand C.

In what type of solution was the human cell placed

What is the percent yield if 0.3 mol ba (no3) 2 and 0.25 mol na3po4 react to produce 0.095 mol ba3 (po4) 2?

H2O (s) ⇒ H2O What would be the best argument against writing this in the form of a chemical equation?

What effect does an increase in products have on the reaction rate of a mixture at equilibrium?

Explain the basic principles of a distillation unit operation

How many valence electrons do the halogens possess?

How calculate how many milliliters of glycerin (specific gravity=1.26) will have a mass of 0.75 lbs?