Question

There are 270 Calories in a Hershey's^{®} Milk Chocolate
bar. The following data might be useful: Δ*H*_{vap}
= 43.9 kJ/mol, Δ*H*_{fusion} = 6.02 kJ/mol,
Δ*H*_{sublimation} = 49.9 kJ/mol, specific heat of
ice = 2.05 J g^{-1}°C^{-1}, specific heat of water
= 4.18 J g^{-1}°C^{-1}, and specific heat of steam
= 2.08 J g^{-1}°C^{-1}. Assume the specific heat of
water does not change with temperature. (Density of ice = 0.920
g/mL).

How much energy is used up at each step of the heating, including heating the solid, melting, heating the liquid, and vaporization? | |

If all of the energy in the bar were used to heat up 75.0 mL of ice at -25.0 °C, how hot would the water get?

Answer #1

A 485.4-g sample of an element at 192°C is dropped into an
ice–water mixture; 117.0 g of ice melts and an ice–water mixture
remains. Calculate the specific heat of the element. ΔHfusion =
6.02 kJ/mol (for liquid water at 0°C). Specific heat =______
J/g∙°C

A 500.0-g sample of an element at 153°C is dropped into an
ice-water mixture; 109.5-g of ice melts and an ice-water mixture
remains. Calculate the specific heat of the element from the
following data:
Specific heat capacity of ice: 2.03 J/g-°C
Specific heat capacity of water: 4.18 J/g-°C
H2O (s) → H2O (l), ΔHfusion: 6.02 kJ/mol (at 0°C)
a) If the molar heat capacity of the metal is 26.31 J/mol-°C,
what is the molar mass of the metal, and what...

What quantity of energy does it take to convert 0.200 kg ice at
–20.°C to steam at 250.°C? Specific heat capacities: ice, 2.03
J/g·°C; liquid, 4.2 J/g·°C; steam, 2.0 J/g·°C; = 40.7
kJ/mol; = 6.02 kJ/mol.
What is the energy in kJ

Calculate the enthalpy change, ΔH, for the process in
which 10.3 g of water is converted from liquid at 9.4 ∘C to vapor
at 25.0 ∘C .
For water, ΔHvap = 44.0 kJ/mol at 25.0 ∘C and
Cs = 4.18 J/(g⋅∘C) for H2O(l).
How many grams of ice at -24.5 ∘C can be completely converted to
liquid at 9.8 ∘C if the available heat for this process is
5.03×103 kJ ?
For ice, use a specific heat of 2.01 J/(g⋅∘C) and...

Calculate the amount of energy necessary to warm 10.0 g of ice
from 0.0° C to 137.0° C. Express your answer in kJ.
Do not enter units of measurement, do not enter the answer in
scientific notation.
The specific heat is 4.184 J/g∙°C for water and 1.99 J/g∙°C for
steam. ΔHvap is 40.79 kJ/mol and ΔHfus is 6.01 kJ/mol.

Which of the following would release the most heat? Assume the
same mass of in each case. Specific heats of ice, liquid water, and
water vapor are 2.05 J/(g⋅°C), 4.18 J/(g⋅°C), and 2.01 J/(g⋅°C)
respectively, the heat of fusion of ice is 6.01 kJ/mol, the heat of
vaporization of water is 40.7 kJ/mol. (Please show your work)
a. Heating the H2) sample from –14°C to 58°C.
b. Cooling the H2O sample from 18°C to –2.3°C.
c. Cooling the sample from...

Part A) Calculate the enthalpy change, ΔH, for the
process in which 38.6 g of water is converted from liquid at 0.3 ∘C
to vapor at 25.0 ∘C .
For water, ΔHvap = 44.0 kJ/mol at 25.0 ∘C and
Cs = 4.18 J/(g⋅∘C) for H2O(l).
Part B) How many grams of ice at -24.6 ∘C can be completely
converted to liquid at 9.4 ∘C if the available heat for this
process is 4.04×103 kJ ?
For ice, use a specific heat...

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)):...

Part A
Calculate the enthalpy change, ΔH, for the process in
which 44.0 g of water is converted from liquid at 7.6 ∘C to vapor
at 25.0 ∘C .
For water, ΔHvap = 44.0 kJ/mol at 25.0 ∘C and
s = 4.18 J/(g⋅∘C) for H2O(l)
Express your answer numerically in kilojoules.
Part B
How many grams of ice at -11.0 ∘C can be completely converted to
liquid at 9.4 ∘C if the available heat for this process is
5.66×103 kJ...

Heat, q, is energy transferred between a system and its
surroundings. For a process that involves a temperature change
q=m?Cs??T where Cs is specific heat and m is mass. Heat can also be
transferred at a constant temperature when there is a change in
state. For a process that involves a phase change q=n??H where, n
is the number of moles and ?H is the enthalpy of fusion,
vaporization, or sublimation. The following table provides the
specific heat and enthalpy...

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