What is a controlled experiment?

A. one variable is changed at a time

B. none of the variables are changed

C. all variables are kept constant

D. two variables are changed at a time

Why is DNA a useful evolutionary clock?

If a temperature increase from 21.0 ∘c to 35.0 ∘c triples the rate constant for a reaction, what is the value of the activation barrier for the reaction?

2. The characteristic bright-line spectrum (color) of an element is produced when A elections are ermitted by the nucleus as beta particles B electrons move to higher energy levels * * C electrons are gained by an atom in D.

13. What salt results from the neutralization of phosphoric acid with potassium hydroxide?

Unknown element X combines with oxygen to form the compound XO2. If 44.0 grams of element X combines with 8.00 grams of oxygen, what is the atomic mass of element X? A. 16 amu B. 44 amu C. 88 amu D. 176 amu E. 352 amu

Consider two solutions, solution a and solution b. [h+] in solution a is 370 times greater than that in solution b. part a what is the difference in the ph values of the two solutions?

All of the following are possible sources of error in a scientific investigation except for O measuring materials such as mass and volume incorrectly. o recording experimental data incorrectly. o having a constant in your experiment.

Do polyatomic ions have fixed charges?

Which type of organism is used to make bread rise when baking? A. plants B. protists C. yeast D. bacteria

How many particles are in 3.55 moles of Aluminum Sulfate