Asealed bottle is full of air. the volume of the bottle is decreased, but the temperature remains constant. what other change occurs in the bottle? a. the air pressure will increase. b. the air pressure will decrease. c. the number of air molecules will increase. d. the number of air molecules will decrease.

Me i dont know what to do! the table compares the number of electrons in two unknown neutral atoms. comparison of electrons atom number of electrons a 10 d 11 use this information to determine the number of valence electrons in the atoms. which of the following correctly compares the stability of the two atoms? both are unreactive. both are highly reactive. a is unreactive and d is reactive. a is reactive and d is unreactive.

Which statement is true about a catalyst? a: a catalyst decreases the rate of the reaction. b. a catalyst is consumed during a chemical reaction. c. a catalyst lowers the activation energy of a reaction. d. a catalyst increases the reactant concentration during a reaction.

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.