Which sample at STP has the same number of atoms as 18 liters of Ne(g) at STP? 1. 18 moles of Ar(g)
2. 18 liters of Ar(g)
3. 18 grams of H2O(g)
4. 18 millimeters of H20(g)

Which part of earth’s surface receives the most direct rays from the sun? a) equator b) ocean c) poles d) mountains

Choose an equation that represents an enzyme-catalyzed reaction. (a) enzyme + substrate → enzyme-substrate complex (b) enzyme + substrate ←−→ enzyme + products (c) enzyme + substrate ←−→ enzyme-substrate complex → enzyme + products (d) enzyme + substrate ←−→ enzyme-substrate complex → enzyme-substrate complex + products

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.