3.2 tons of coal is used to provide enough heat to bring the temperature of 2.0 x l05 gallons of water up 300 f. the heat value of one ton of coal is 2.5 x107 btu/ton. one gallon of water weighs 8 lbs and btu’s are calculated by multiplying pounds of water by their change in temperature in degrees fahrenheit. what is the efficiency?

Extensive and unusual cold snaps have occurred here recently. is this evidence that global warming is lessening or not occurring? no—although the long-term trend is for warming, short-term weather patterns can still be variable. no—melting of glaciers and ice caps is making the oceans cooler, which can cause cold snaps. yes-- if global warming really were occurring, cold snaps wouldn’t happen. yes—due to global warming, weather patterns should be become less—not more—variable.