Cold packs contain chemical that react to absorb heat. Which substances is used in cold packs?

A. Calcium Chloride

B. Sodium Carbonate

C. Magnesium sulphate

D. Ammonium nitrate

Coefficients should always: A) be whole numbers B) use the lowest possible ratios C) use the values of 1, 2, 3, or 4 D) both choices a and b

Which of the following elements does NOT form a monatomic ion? sodium nitrogen helium oxygen

If a certain compound has a formula H2X. What is the Valency of X?

Can atoms change identity during a chemical reaction

Which statement about the relationship between laws, hypotheses, and theories is true? A. Laws that remain true over an extended period of time are considered theories. B. A theory that holds true for a long time is considered a law. C.

Calculate the acid dissociation constant of a weak monoprotic acid if a 0.5M solution of this acid gives a hydrogen-ion concentration of 0.000 1M? Show your work.

Which orbital notation represents a noble gas in the ground state

c. When we heat water up by the Bunsen burner, what temperature is the boiling water? After 10 minutes

Assuming that air contains 78 percent N2, 21 percent O2 and 1 percent Ar, all by volume. How many molecules of each type of gas are present in 1.0 L of air at STP?

Two children are playing tag. Child A who is doing the chasing can run 100m in 24 seconds Child B is running away from child A and can run 64m in 21 seconds.