Which of the following is true for combustion reactions?

energy is absorbed.
energy is released.
hydrogen is a reactant.
nitrogen is a reactant.

Which of the following methods uses the decay of atomic particles in an object to find its exact age? a. fossil dating b. geologic dating c. radioactive dating d. relative dating

High-pressure liquid chromatography (hplc) is a method used in chemistry and biochemistry to purify chemical substances. the pressures used in this procedure range from around 500 kilopascals (500,000 pa) to about 60,000 kpa (60,000,000 pa). it is often convenient to know the pressure in torr. if an hplc procedure is running at a pressure of 1.03×108 pa , what is its running pressure in torr?

What is the morality of 2.50 l of solution that contains 1.85 mol of anhydrous sodium tetraborate?