Determine whether each of the following is exothermic or endothermic and indicate the sign of? h.
a. natural gas burning on a stove
b. isopropyl alcohol evaporating from skin
c. water condensing from steam

indicate the sign of δh.

which one is positive and which one is negative?

Simple machines can a. increase force only b. decrease force only c. increase or decrease force

In a heat engine if 1000 j of heat enters the system the piston does 500 j of work, what is the final internal energy of the system if the initial energy was 2000 j? 1. write the equation 2.list out your known variables 3.plug the numbers into the equations 4.solve 5.write your solution statement that includes initial energy and final

An ice-making machine inside a refrigerator operates in a carnot cycle. it takes heat from liquid water at 0.0 degrees celsius and rejects heat to a room at a temperature of 19.2 degrees celsius. suppose that liquid water with a mass of 76.3kg at 0.0 degrees celsius is converted to ice at the same temperature. take the heat of fusion for water to be l_f = 3.34*10^5 j/kg.how much energy e must be supplied to the device? express your answer in joules.