Chemistry Homework Help

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Heating and Cooling Curves

#### Q. Consider the following specific heat capacities: H2O(s) = 2.09 J/g.°C H2O(l) = 4.18 J/g.°C H2O(g) = 2.03 J/g.°C The heat of fusion for water is 334 J/g and its heat of vaporization is 2260 J/g. Calculate the amount of heat required to convert 93 g of ice at -36°C completely to liquid water at 35°C. a) 38 kJ b) 21 kJ c) 7 kJ d) 52 kJ

Solved • Nov 19, 2019

Heating and Cooling Curves

#### Q. A balloon is filled with 1.56 * 10^22 atoms of xenon at 23C. After a brief period of cooling, the ballon's volume is measured to be 615 ml. How much heat energy (in J) did the gas lose? The density of xenon gas at 23C is 5.406g/L.

Solved • Nov 12, 2019

Heating and Cooling Curves

#### Q. What mass of this substance must evaporate to freeze 200 g of water initially at 25 ∘C? (The heat of fusion of water is 334 J/g; the specific heat of water is 4.18 J/(g⋅K).) Express the mass in grams to two significant digits.

Solved • Nov 12, 2019

Heating and Cooling Curves

#### Q. How long would it take for 1.50 mol of water at 100.0 ∘C to be converted completely into steam if heat were added at a constant rate of 18.0 J/s ? Express your answer to three significant figures and include the appropriate units.

Solved • Nov 12, 2019

Heating and Cooling Curves

#### Q. What is the energy change (in kJ) when 38.5 g of water vapor (or steam) at 135°C is cooled to 95°C? Hint: Cice = 2.09 J/(g·°C), Cwater = 4.18 J/(g·°C), Csteam = 2.00 J/(g·°C) Hint: ΔHfus = 6.02 kJ/mol, ΔHvap = 40.7 kJ/mol

Solved • Nov 7, 2019

Heating and Cooling Curves

#### Q. determine the amount of heat (in KJ) required to convert 50.5g of ice at 0C to steam at 100C.

Solved • Oct 20, 2019

Heating and Cooling Curves

#### Q. The following information is given for benzene at 1.00 atm: ΔHvap=30.77 kJ mol^-1 ΔHfus=9.90 kJ mol^-1 bp=80.1 degrees C mp=5.5 degrees C Cgas=1.04 J g^-1 degrees C^-1 Cliquid=1.74 J g^-1 degrees C^-1 The initial temperature of a 102.0 g sample of benzene (C6H6) is 95.2 degrees C. Find the amount of heat (in kJ to the nearest whole number) that must be removed from the system to decrease the temperature to 6.50 degrees C.

Solved • Sep 25, 2019