Cesium-137 has a half-life of 30 years. You find a sample with 3 g of cesium-137. How much cesium-137 existed in the sample 90 years ago?

Finding the pH for [H+] = 9.4 * 10-3 M?

What is the total number of orbitals in the fourth main energy level? 4 9 16 1

A 250 ml flask and stopper have a mass of 110.525 g. A 50 ml sample of gasoline is pipetted into the flask, giving a total mass of 146.770 g. Find the density of the gasoline

When hydrogen ions combine with hydroxide ions the resulting molecule is considered?

A gas occupies 3.5 L at standard pressure. Find the volume of the gas when the pressure is 1.5 atm.

Which of the following radioactive emissions is the least penetrating, aloha particles, beta particles or gamma rays

The three major groups p On the periodic table are the

Which of the following has the greatest mass, in grams? a. 1 atom of lead (Pb) b. 0.5 mol copper (Cu) atoms c. 0.3 mol gold (Au) atoms d. 25 atoms of mercury (Hg)

Which one is not a sedimentery rock a.) sandstone b.) limestone c.) quartz d. (coal

Which group is more reactive than the alkaline earth metals?