Question

In a coffee-cup calorimeter experiment, 10.00 g of a soluble ionic compound was added to the calorimeter containing 75.0 g H2O initially at 23.2°C. The temperature of the water increased to 31.8°C. What was the change in enthalpy for the dissolution of the compound? Give your answer in units of joules per gram of compound. Assume that the specific heat of the solution is the same as that of pure water, 4.18 J ⁄ (g ⋅ °C).

Answer #1

In chemistry, the point of view is the system, not the surroundings. The system in this case is the chemical and its dissolving. The surroundings would be the water which absorbs the heat. Since this reaction is exothermic, the proper sign in chemistry would be negative.

q =You know have 85 g of solution * 4.18 J/gC * (31.8C - 23.2C)
= 3055 J. As energy is given offl the sign should be
negative.

Since you had 10 g of the original solid, the result is -305.5 J/g
or -3.1 * 10^2 J/g

In the following experiment, a coffee-cup calorimeter containing
100. mL of H2O is used. The initial temperature of the calorimeter
is 23.0 ∘C. If 2.00 g of CaCl2 is added to the calorimeter, what
will be the final temperature of the solution in the calorimeter?
The heat of solution, ΔHsoln, of CaCl2 is −82.8 kJ/mol. The
specific heat of water is CS=4.184 J/(g−K

A student determines the heat of dissolution of solid
ammonium bromide using a coffee-cup calorimeter of
negligible heat capacity.
When 6.34 g of
NH4Br(s) is dissolved in
119.00 g of water, the temperature of the solution
drops from 25.00 to 22.76 °C.
Based on the student's observation, calculate the enthalpy of
dissolution of NH4Br(s) in kJ/mol.
Assume the specific heat of the solution is 4.184 J/g°C.
ΔHdissolution = kJ/mol

When 10.0 g KOH is dissolved in 100.0 g of water in a coffee-cup
calorimeter, the temperature rises from 25.18 ˚C to 47.53 ˚C.
Calculate the ∆Hrxn for the dissolution process. Assume that the
solution has a specific heat capacity of 4.184 J/gK

In the following experiment, a coffee-cup calorimeter containing
100 mL of H2O is used. The initial temperature of the calorimeter
is 23.0 ∘C. If 2.60 g of CaCl2 is added to the calorimeter, what
will be the final temperature of the solution in the calorimeter?
The heat of solution ΔHsoln of CaCl2 is −82.8 kJ/mol.

In the following experiment, a coffee-cup calorimeter containing
100 mL of H2O is used. The initial temperature of the calorimeter
is 23.0 ∘C. If 8.10 g of CaCl2 is added to the calorimeter, what
will be the final temperature of the solution in the calorimeter?
The heat of solution ΔHsoln of CaCl2 is −82.8 kJ/mol.

In the following experiment, a coffee-cup calorimeter containing
100 mL of H2O is used. The initial temperature of the calorimeter
is 23.0 ∘C. If 8.70 g of CaCl2 is added to the calorimeter, what
will be the final temperature of the solution in the calorimeter?
The heat of solution ΔHsoln of CaCl2 is −82.8 kJ/mol.

In the following experiment, a coffee-cup calorimeter containing
100 mL of H2O is used. The initial temperature of the calorimeter
is 23.0 ∘C. If 9.70 g of CaCl2 is added to the calorimeter, what
will be the final temperature of the solution in the calorimeter?
The heat of solution ΔHsoln of CaCl2 is −82.8 kJ/mol.

In the following experiment, a coffee-cup calorimeter containing
100 mL of H2O is used. The initial temperature of the calorimeter
is 23.0 ∘C. If 3.50 g of CaCl2 is added to the calorimeter, what
will be the final temperature of the solution in the calorimeter?
The heat of solution ΔHsoln of CaCl2 is −82.8 kJ/mol.

A coffee-cup calorimeter initially contains 125 g water at 24.2
degrees celsius. Ammonium Nitrate (10.5 g), also at 24.2 degree
celsius, is added to the water, and after the ammonium nitrate
dissolves, the final temperature is 18.3 degrees celsius.What is
the heat of solution of ammonium nitrate in kj/mol? Assume that the
specific heat capacity of the solution is 4.18 J/Cg and that no
heat is transferred to the surrounds or to the calorimeter.

In the laboratory a
"coffee cup" calorimeter, or constant
pressure calorimeter, is frequently used to determine the specific
heat capacity of a solid, or to measure the enthalpy of a solution
phase reaction.
Since the cup itself can absorb energy, a separate experiment is
needed to determine the heat capacity of the calorimeter. This is
known as calibrating the calorimeter and
the value determined is called the calorimeter
constant.
One way to do this is to use a common metal...

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