Calculate the heat energy required to convert 4kg of ice at -25℃, to stem, at 100℃, given the specific heat capacity of water is 4200J/(kg℃), , the specific heat capacity of ice is 2100J/(kg℃), the specific latent heat of vaporization of water is 2300 000J/kg.

An object weigh 40n in air ,weigh 20n when submerged in water, and 30n when submerged in a liquid of unknown liquid density. what is the density of unknown of liquid?

Achlorine atom has 17 protons and 18 neutrons. what is its mass number? what is its atomic number?

An ideal otto cycle has a compression ratio of 8. at the beginning of the compression process, air is at 95 kpa and 27°c, and 750 kj/kg of heat is transferred to air during the constant-volume heat-addition process. assuming constant specific heats at room temperature, determine (a) the pressure and temperature at the end of the heat-addition process, (b) the net work output, (c) the thermal efficiency, and (d) the mean effective pressure for the cycle. (4390 kpa, 1730 k; 423 kj/kg; 56.4%; 534 kpa)