Most people find waterbeds uncomfortable unless the water temperature is maintained at about 85 °f. unless it is heated, a waterbed that contains 892 l of water cools from 85 °f to 72 °f in 24 hours. estimate the amount of electrical energy required over 24 hours, in kwh, to keep the bed from cooling. note that 1 kilowatt-hour (kwh) = 3.6 × 106 j, and assume that the density of water is 1.0 g/ml (independent of temperature). what other assumptions did you make? how did they affect your calculated result (i. e., were they likely to yield "positive" or "negative" errors)?

This active feature of earth's crust in building mountain ranges as well as islands. this feature is a a) cavern. b) earthquake. c) mountain. d) volcano.

Two nitro no2 groups are chemically bonded to a patch of surface. they can't move to another location on the surface, but they can rotate (see sketch at right). it turns out that the amount of rotational kinetic energy each no2 group can have is required to be a multiple of ε, where =ε×1.010−24 j. in other words, each no2 group could have ε of rotational kinetic energy, or 2ε, or 3ε, and so forth — but it cannot have just any old amount of rotational kinetic energy. suppose the total rotational kinetic energy in this system is initially known to be 32ε. then, some heat is removed from the system, and the total rotational kinetic energy falls to 18ε. calculate the change in entropy. round your answer to 3 significant digits, and be sure it has the correct unit symbol.

Explain the relationship between forward and backward reactions in equilibrium, and predict how changing the amount of a reactant (creating a tension) will affect that relationship.