4. Which of the following units are not paired correctly? a) Liter (L) - Mass
b) Newton (N) - Force
c) Pascal (P) - Pressure
d) Joule (J) - Work

1. explain hydrogen peroxide, h 2 o 2 properties and decomposition reaction. 2. describe how each of the following natural cycles plays a part in earth’s climate system. (a) the water cycle (b) the carbon cycle

15. which of the following is not human-caused groundwater pollution? a. water in an aquifer dissolves elements such as arsenic and mercury from surrounding rock. b. water in an aquifer is contaminated by leachate that seeps into the ground from a landfill. c. water in an aquifer becomes polluted with chemicals used in hydraulic fracturing, or fracking. d. water in an aquifer absorbs harmful bacteria from the drainage field of a septic tank.

The characteristics of two different types of reactions are shown below: reaction a: electrons are gained by the atoms of an element. reaction b: protons are lost by the atom of an element. which statement is true about the atoms of the elements that participate in the two reactions? their identity changes in both reaction a and reaction b. their identity changes in reaction a but not in reaction b. their identity changes in reaction b but not in reaction a. their identity remains the same in both reaction a and reaction b.