As NH4Cl dissolves in water, and cools the solution, a. delta H is negative, and delta S is negative
b. delta H is positive, and delta S is negative
c. delta H is negative, and delta S is positive
d. delta H is positive, and delta S is positive

pure substance: iron,copper

impure substance: water,charcoal

8 m/s because for him to get the same amount of energy as ray is putting out, bobby, who weighs half as much as ray, needs to run twice as fast.

aquifers are bounded above and below by impermeable rock. the driving force of groundwater movement in confined aquifers is pressure, rather than gravity.

2b2t

explanation:

2b2t