Praxis Middle School Science-Chemical Reactions

Question 1

endothermic chemical reaction

Answer 1

one in which more energy is needed to break the reactant bonds than is released when product bonds form, so heat is absorbed

Question 2

exothermic chemical reaction

Answer 2

one in which more energy is released through product bond formation than is needed to break reactant bonds, so heat is released

Question 3

activation energy

Answer 3

the amount of energy needed for the reaction to start

Question 4

maxwell-bolzmann distributions

Answer 4

graphed curves showing the effect of temperature on the distribution of kinetic energies in a sample of molecules

Question 5

reaction rates increase with

Answer 5

reactant concentration

Question 6

catalyst

Answer 6

a material that increases the rate of a chemical reaction without changing itself permanently in the process

Question 7

catalysts have no impact on

Answer 7

the chemical equilibrium of a reaction

Question 8

a catalyst increases the rate of

Answer 8

both the forward and reverse reactions by lowering the activation energy for the reaction

Question 9

enzymes

Answer 9

a biological catalyst

Question 10

chemistry is important to the earth sciences because

Answer 10

the joining and dissolution of elements form the basic structures of the various minerals that make up earth materials

Question 11

if elements combine by sharing electrons, the interactions can result in materials that are…

Answer 11

extremely resistant to weathering (ex: granite)

or conversely, highly susceptible to erosive processes (ex: sandstone).