Which statement about reaction rates is true?

a. a catalyst slows down the reaction rate.
b. changing the surface area affects the reaction rate.
c. changing the amount of reactants will not change the reaction rate.
d. changing the temperature cannot speed up a reaction rate.

Which object forms when a supergiant runs out of fuel? a red giant a black hole a white dwarf a neutron star

An object becomes electrically charged when: electrons are created in it electrons from it are destroyed electrons are transferred to it protons from it are destroyed protons are created in it

What amount of heat is exchanged when 106.2 grams of substance y goes from a liquid at 35 degrees celsius to a solid at the same temperature? melting point of substance y = 35 degrees c; δhvaporization = 3.67 j/mol; δhfusion = 3.30 j/mol. mwsubstance y = 28.22 g/mol. −12.4 j −3.51 x 102 j 1.24 x 101 j 351 j