When the equation Al + Br2 → AlBr3 is balanced, the coefficient for Br2 isSingle choice.

If the root word engage means “to connect with something,” what does the word disengage mean in the following sentence? he disengaged the gears by stepping on the clutch pedal. a.added more engine powerb. activated a connection to the pedalc. stalled the engined. released a connection to the pedal

Which of the following statements is true? a. elements in the last period are radioactive. b. atomic weight is the same as atomic mass. c. elements in the same group have the same number of electron shells. d. atomic number equals the number of neutrons in the nucleus of an atom.

1.) which of the following is a molecule but not a compound? a. he b. f2 c. h2o d. ch4 2.) what is a physical combination of substances? a. a compound b. a molecule c. a mixture d. an element 3.) what is a chemical combination of substances? a. a compound b. an atom c. a mixture d. an element 4.) what is the relationship between the solute and solvent in a solution? a. they form a compound b. they form a mixture c. they form molecules d. they form chemical bonds 5.) the gases in air dissolve in water. what would be one way to reduce the amount of a gas dissolved in water? a. add more water b. reduce the air pressure c. increase the air pressure d. stir the water 6.) how would you determine the solubility of a substance? a. find how well it dissolved various substances. b. find the mass and the volume of the substance. c. find the temperature at which the substance evaporated. d. find how much i was able to dissolve in a solute. 7.) the periodic table organizes all of the kinds of a. molecules. b. compounds. c. atoms. d. ions. 8.)what distinguishes two substances combined to become a compound vs. two substances combined to become a mixture? a. whether they can be easily separated b. whether they chemically bond together c. whether they both are visible d. whether they are heterogeneous 9.) the principle components of air are: n2 78% o2 21% ar 0.95% co2 0.038% this is a solution of a. molecules and atoms. b. molecules. c. compounds and molecules. d. atoms.