What are the roles of hydrogen peroxide, oxygen, hydrogen, and catalase in the following chemical reaction?
catalase: 2h2o2 --> 02 + 2h2o

a. catalase is an enzyme, o2 and h2o are substances, and h2o2 is a reactant.
b. catalase is a substrate, o2 and h2o are products, and h2o2 is an enzyme.
c. catalase is a substrate, o2 and h2o are products, and h2o2 is an enzyme.
d. catalase is an enzyme, o2 and h2o are products, and h2o2 is a substrate.

Chen drew a diagram to compare the ways in which different organisms obtain nitrogen. which label belongs to the area marked z?

16. why must the number of electrons lost equal the number of electrons gained in every redox reaction? use 3 – 4 sentences in your own words to address this question. 18. what type of radiation is emitted when chromium-51 decays into manganese-51? show the nuclear equation that leads you to this answer. 19. a radioactive nucleus alpha decays to yield a sodium-24 nucleus in 14.8 hours. what was the identity of the original nucleus? show the nuclear equation that leads you to this answer.

6. using 3 – 4 sentences explain (in your own words) why water expands when it freezes? 7. using your knowledge of colligative properties explain whether sodium chloride or calcium chloride would be a more effective substance to melt the ice on a slick sidewalk. use 3 – 4 sentences in your explanation.