Question

How much heat is released when 105 g of steam at 100.0°C is cooled to ice at -15.0°C? The enthalpy of vaporization of water is 40.67 kJ/mol, the enthalpy of fusion for water is 6.01 kJ/mol, the molar heat capacity of liquid water is 75.4 J/(mol • °C), and the molar heat capacity of ice is 36.4 J/(mol • °C).

Answer #1

Heat released when water vapour is condensed to liquid(q1)

No of mole = 105g/18.013g/mol =5.829

∆H_{cond}= -40.67kJ/mol

q1 = -40.67kJ/mol × 5.829mol = -237.1kJ

Heat released when liquid water is cooled from 100℃ to 0℃ (q2)

q2 = n × ∆T × C_{water}

=- (5.829mol × 100℃ × 75.4J/mol ℃)

= - 43.95kJ

Heat released when liquid water freeze to ice(q3)

∆H_{freeze} = -6.01kJ/mol

q3 =- (6.01 kJ/mol × 5.829 mol =-35.03kJ

Heat released when ice is cooled from 0℃ to -15℃ (q4)

q4 = -(n × ∆T × C_{ice})

_{ =- ( 5.829mol × 15℃ × 36.4J/mol℃)}

_{ = -3.18kJ}

_{Total heat release = q1 + q2 + q3 + q4}

_{ = - ( 237.1kJ + 43.95kJ + 35.03 +
3.18)}

_{ = -319.3kJ}

_{Therefore,}

_{319.3kJ of heat is released}

part A How much heat energy, in
kilojoules, is required to convert 69.0 g of ice at −18.0 ∘C to
water at 25.0 ∘C ? Part B 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 22.0 J/s ?
Specific heat of ice: sice=2.09 J/(g⋅∘C)
Specific heat of liquid water: swater=4.18 J/(g⋅∘C)
Enthalpy of fusion (H2O(s)→H2O(l)): ΔHfus=334 J/g
Enthalpy of vaporization (H2O(l)→H2O(g)):...

A 1.000 kg block of ice at 0 °C is dropped into 1.354 kg of
water that is 45 °C. What mass of ice melts?
Specific heat of ice = 2.092 J/(g*K) Water = 4.184
J/(g*K) Steam = 1.841 J/(g*K) Enthalpy of fusion =
6.008 kJ/mol Enthalpy of vaporization = 40.67 kJ/mol

What is the change in enthalpy (∆H) when a 147g of ice at
-23.7°C is heated to a liquid at 66.5°C? The specific heats of ice,
liquid water, and steam are 2.03, 4.18, and 1.84 J/g°C,
respectively. For water, ∆Hvap = 40.67 kJ/mol and ∆Hfus = 6.01
kJ/mol.

How much energy (in kilojoules) is needed to heat 4.65 g of ice
from -11.5 ∘C to 20.5 ∘C? The heat of fusion of water is
6.01kJ/mol, and the molar heat capacity is 36.6 J/(K⋅mol) for ice
and 75.3 J/(K⋅mol) for liquid water.

a/ Compute the quantity of heat released by 25.0 g of steam
initially at 100.0 oC, when it is cooled to 34.0°C and by 25.0 g of
water initially at 100.0 oC, when it is cooled to 34.0°C. b/ You
put your hand into this steam or this water (which is not
recommended!), in which case your hand will be burnt more severely?
Explain. The heat of vaporization of water is 2.256×106 J/kg and
the specific heat of water is...

a/ Compute the quantity of heat released by 25.0 g of steam
initially at 100.0 oC, when it is cooled to 34.0°C and by 25.0 g of
water initially at 100.0 oC, when it is cooled to 34.0°C.
b/ You put your hand into this steam or this water (which is not
recommended!), in which case your hand will be burnt more severely?
Explain. The heat of fusion of water is 2.256×106 J/kg and the
specific heat of water is...

4. Steam is condensed at 100oC to water which is
cooled to 0oC and frozen to ice. What are the molar
enthalpy and entropy changes for this process? Assume that the
average specific heat of water is 4.2JK-1 g-1
and the enthalpy of vaporization at the boiling point and the
enthalpy of fusion at the freezing point are 2258.1 and 333.5 J
g-1 respectively.
(Note: Convert Jg-1 to J mol-1)

Please show each step. Thank you.
How much heat (in kJ) is evolved in converting 1.00 mole of
steam at 145.0 °C to ice at -50.0 °C? The heat capacity of ice is
2.09 J/g°C and that of steam is 2.09 J/g°C
Heat of fusion for water • Hfus = 6.02 kJ/mol
Heat of vaporization for water • Hvap = 40.7 kJ/mol

How much energy (in kilojoules) is released when 22.0 g of
ethanol vapor at 97.5 ∘C is cooled to -12.5 ∘C? Ethanol has mp =
-114.5 ∘C, bp = 78.4 ∘C, ΔHvap = 38.56 kJ/mol and ΔHfusion = 4.60
kJ/mol. The molar heat capacity is 113 J/(K⋅mol) for the liquid and
65.7 J/(K⋅mol) for the vapor.

Two 20.0-g ice cubes at –20.0 °C are placed into 285 g of water
at 25.0 °C. Assuming no energy is transferred to or from the
surroundings, calculate the final temperature, Tf, of the water
after all the ice melts. heat capacity of H2O(s) is 37.7 J/mol*K
heat capacity of H2O(l) is 75.3 J/mol*K enthalpy of fusion of H20
is 6.01 kJ/mol

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