(II) If the humidity in a sealed room of volume 420m3 at20°C is 65%, what mass of water can still evaporate froman open pan?

(II) How much heat is needed to melt 23.50 kg of silverthat is initially at 25°C?

(II) An iron boiler of mass 180 kg contains 730 kg of water at 18°C. A heater supplies energy at the rate of 58000 KJ/h How long does it take for the water (a) to reach the boiling point, and (b) to all have changed to steam?

(II) If the air pressure at a particular place in the mountainsis 0.80 atm, estimate the temperature at which water boils.

(III) Approximately how long should it take 8.2 kg of ice at 0°C to melt when it is placed in a carefully sealed Styrofoam ice chest of dimensions 25cmx 35cm x55 cm whose walls are 1.5 cm thick? Assume that the conductivity of Styrofoam is double that of air and that the outside temperature is 34°C.

(4) A mass of 3.25 kg of R-134a fill a piston-cylinder device with and initial volume of 0.246 m³ at a temperature of – 10.09°C. The refrigerant is now heated until the temperature is 50°C. The final volume of the R-134a is: - (a) 0.383 m (b) 0.415 m³ (c) 0.438 m³ (d) 0.467 m3 (e) 0.491 m² 3

(II) A 215-g sample of a substance is heated to 330°C and thenplunged into a 105-g aluminum calorimeter cup containing185 g of water and a 17-g glass thermometer at 10.5°C.The final temperature is 35.0°C. What is the specific heatof the substance? (Assume no water boils away.)

(I) What is the partial pressure of water vapor at 30°C ifthe humidity is 75%?

(I) An automobile cooling system holds 18 L of water. Howmuch heat does it absorb if its temperature rises from 15°Cto 95°C?