Determine the empirical formula of an organic hydrocarbon compound that contains 80% by mass of carbon and 20% by mass of hydrogen. If the Mr of the compound is 30, what is the molecular formula?

Potassium forms an oxide containing 1 oxygen atom for every 2 atoms of potassium. what is the coefficient of oxygen in the balanced equation for the reaction of potassium with oxygen to form this oxide?

How much sucrose (g) do you need to weight in order to prepare 19.16 g of a 13.1 % (weight percent) solution?

Explain why some pesticides bioaccumulate whereas others do not

1. Which gas will move faster through a small opening hydrogen or oxygen? * A) hydrogen B) oxygen

Historically, the medical consequence suffered by consumers exposed to lead is A.) Stunted growth B.) infection C.) rashes D.) brain damage

Small beads of iridium-192 are sealed in a plastic tube and inserted through a needle into breast tumors. If an Ir-192 sample has an initial activity of 560 dpm, how much time is required for the activity to drop to 35 dpm (t1/2 = 74 days) ?

Consider the following equation. 2H2 (g) + O2 (g) 2H2O (g); ΔH is negative. Which statement is true? The reaction is endothermic from left to right. Increased pressure would increase the rate of forming water vapor.

Ions form when atoms gain or lose protons. True or False.

In which of the following aqueous solutions would you expect AgI to have the highest solubility? In which of the following aqueous solutions would you expect AgI to have the highest solubility? 0.038 M NaI 0.050 M AgNO3 0.025 M KI 0.

If the passing of five half-lives leaves 25 mg of a strontium-90 sample, how much was present in the beginning?