In an elastic collision kinetic energy is transferred from one particle to another but the total kinetic energy remains constant is this always true ? some times true ? or never true ?

As we move from left to right across the periodic table, what is the general trend? a) atomic radii increase. b) electronegavitiy decreases. c) nuclear shielding increases. d) metallic character decreases.

Two solids are mixed in a flask and stirred. after a few minutes, the flask becomes cold. which of the following best describes this reaction? a. an exothermic reaction b. a combustion reaction c. an endothermic reaction d. a decomposition reaction

Achemist needs to prepare a buffer solution of ph 8.80. what molarity of nh3 (pkb = 4.75) is required to produce the buffer solution if the (nh4)2so4 in the solution is 1.8 m?