Question 1

Calculate the final temperature of 68.4 g of molecular hydrogen (specific heat capacity = 14.304 J g^-1 °C^-1)initially at 8.24 °C that releases 25.3 kJ of energy into the surroundings.

Accepted Answer

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Question 2

An unknown metal alloy,mass = 36.1 g,has a temperature change of 31.6 to 24.8 °C after a heat transfer of -103.0 J.Calculate the specific heat capacity of the alloy.

Accepted Answer

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Question 3

A piece of iron (mass = 25.0 g)at 398 K is placed in a styrofoam coffee cup containing 25.0 mL of water at 298 K.Assuming that no heat is lost to the cup or the surroundings,what will the final temperature of the water be? The specific heat capacity of iron = 0.449 J $g ^ { - 1 }$ °C^-1 and water = 4.184 J $g ^ { - 1 }$ °C^-1.

Accepted Answer

The heat lost by iron equals the heat gained by water. Using the formula $q = mc\Delta T$, set up the equation: $ (25.0 \, \text{g})(0.449 \, \text{J/g°C})(T_f - 398 \, \text{K}) = (25.0 \, \text{g})(4.184 \, \text{J/g°C})(T_f - 298 \, \text{K}) $. Solving for $T_f$ gives approximately 308 K.

Question 4

Calculate the heat transfer (J)when 3.15 g of platinum (specific heat capacity = 0.133 J g^-1 °C^-1)at 86.1 °C cools to room temperature,24.3 °C.

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Question 5

Calculate the initial temperature of 648 g of cucumber (specific heat capacity = 1.88 J g^-1 °C^-1)that absorbs 19857 J of heat while warming up to room temperature,24.8 °C.

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Question 6

Calculate the heat transfer,in kJ,when 1.287 kg of chicken breast (specific heat capacity = 1.82 J g^-1 °C^-1)is removed from a freezer at -17.3 °C and allowed to warm up to 0.00 °C.You need not be concerned about melting of ice or any other phase changes.

Accepted Answer

First, we need to find the change in temperature (ΔT) of the chicken breast:
ΔT = 0 °C - (-17.3 °C) = 17.3 °C

Next, we can calculate the heat transfer using the formula:
q = m * c * ΔT
where q is the heat transfer in Joules, m is the mass in kg, c is the specific heat capacity in J/g°C, and ΔT is the change in temperature in °C.

Converting the units of specific heat capacity to J/kg°C:
1.82 J/g°C * (1 kg / 1000 g) = 0.00182 J/kg°C

Plugging in the values:
q = (1.287 kg) * (0.00182 J/kg°C) * (17.3 °C)
q = 0.0405 kJ

Therefore, the heat transfer is 40.5 kJ, which is option D.

Question 7

A student is preparing to perform a series of calorimetry experiments.She first wishes to determine the calorimeter constant (C_ca_l)for her coffee cup calorimeter.She pours a 50.0 mL sample of water at 345 K into the calorimeter containing a 50.0 mL sample of water at 298 K.She carefully records the final temperature of the water as 317 K.What is the value of C_calfor the calorimeter?

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Question 8

Calculate the initial temperature of 21.8 g of lithium (specific heat capacity = 3.582 J g^-1 °C^-1)that absorbs 1642 J of energy from the surroundings and has a final temperature of 31.08 °C.

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Question 9

Astatine is an extremely rare element with an estimated 28 g total on Earth.How much energy would be required to heat Earth's entire supply of astatine by 10.0 °C assuming it has a specific heat capacity similar to iodine,0.214 J g^-1 °C^-1?

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Question 10

Calculate the final temperature of 82.1 g of molecular hydrogen (specific heat capacity = 14.304 J g^-1 °C^-1)initially at 5.48 °C that absorbs 57 kJ of energy from the surroundings.

Accepted Answer

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Question 11

Which of the following statements is TRUE?

Accepted Answer

A) This is a fundamental concept in thermodynamics, known as the First Law of Thermodynamics.
B) S, U, and B refer to entropy, internal energy, and molar number of substance, respectively, and Dr denotes a reaction. This statement does not make sense on its own, so it is unclear if it is true or false.
C) This is also known as the Law of Conservation of Energy, and is a fundamental concept in thermodynamics and physics.
D) This statement is true, as the symbol H refers to enthalpy, which is a state function that can be determined using constant pressure calorimetry.

Question 12

Calculate the initial temperature of 448 g of grapes (specific heat capacity = 1.76 J g^-1 °C^-¹)that absorb 17472 J of heat while warming up to room temperature,23.1 °C.

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Question 13

A 100.0 mL sample of 0.300 mol L^-1 NaOH is mixed with a 100.0 mL sample of 0.300 mol L^-1 HNO₃ in a coffee cup calorimeter.If both solutions were initially at 35.00 °C and the temperature of the resulting solution was recorded as 37.00 °C,determine the $D _ { \mathrm { r } }$ H° (in units of kJ $\mathrm { mol } ^ { - 1 }$ )for the neutralization reaction between aqueous NaOH and HNO₃ .Assume 1)that no heat is lost to the calorimeter or the surroundings,and 2)that the density and the heat capacity of the resulting solution are the same as water.

Accepted Answer

First, we need to calculate the heat absorbed by the reaction (qrxn). qrxn = -qcal = -Ccal(Tfinal - Tinitial) where Ccal is the heat capacity of the calorimeter and can be calculated using the mass of the water in the calorimeter and its heat capacity. Since the density and heat capacity of the solution are assumed to be the same as water, we can assume that the mass of the water in the calorimeter is 200.0 g (100.0 mL + 100.0 mL) and its heat capacity is 4.184 J/g°C. Therefore, Ccal = (200.0 g)(4.184 J/g°C) = 836.8 J/°C. Next, we need to calculate the amount of heat produced by the reaction. We can do this by calculating the amount of moles of either NaOH or HNO₃ that reacted and using the molar enthalpy of the reaction. Since the two solutions have the same concentration and volume, we can assume that they reacted completely in a 1:1 stoichiometric ratio. Therefore, the amount of moles of either reactant can be calculated as: n = (0.300 mol/L)(0.100 L) = 0.0300 mol Now we can use the molar enthalpy of the reaction to calculate the amount of heat produced: qrxn = nΔH°rxn Since ΔH°rxn is what we're trying to find, we can rearrange the equation to solve for it: ΔH°rxn = qrxn/n Plugging in the values we found earlier: qrxn = -Ccal(Tfinal - Tinitial) = -(836.8 J/°C)(37.00°C - 35.00°C) = -1673.6 J ΔH°rxn = -1673.6 J / 0.0300 mol = -55,787.6 J/mol Converting to kJ/mol gives us an answer of -55.8 kJ/mol, which is closest to choice A. Therefore, the answer is A.

Question 14

An unknown metal alloy,mass = 26.3 g,has a temperature increase of 8.31 °C after a heat transfer of 94.0 J.Calculate the specific heat capacity of the alloy.

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Question 15

Calculate the enthalpy of solution for the dissolution of sodium chloride,NaCl,molar mass = 58.443 g mol^-1.When 6.93 g of NaCl is dissolved in a coffee cup calorimeter containing 100.0 mL of water the temperature dropped from 23.5 °C to 22.4 °C.The specific heat of water is 4.184 J g^-1 °C^-1,and assume the density of the solution is 1.00 g mL^-1.

Accepted Answer

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Question 16

An unknown metal alloy,specific heat capacity = 0.372 J g^-1 °C^-1,has a temperature change of +21.7 °C after a heat transfer of 216.4 J.Calculate the mass of the alloy in question.

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Question 17

Two aqueous solutions are both at room temperature and are then mixed in a coffee cup calorimeter.The reaction causes the temperature of the resulting solution to fall below room temperature.Which of the following statements is TRUE?

Accepted Answer

The reaction is endothermic because the temperature of the solution decreases, indicating that energy is absorbed from the surroundings. Therefore, none of the statements A, B, C, or D are true.

Question 18

Calculate the final temperature of 6.84 g of praseodymium (specific heat capacity = 0.193 J g^-1 °C^-1)initially at 26.8 °C that releases 11.3 J of energy into the surroundings.

Accepted Answer

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Question 19

An unknown metal alloy,specific heat capacity = 0.613 J g^-1 °C^-1,has a temperature change of 31.02 to 24.77 °C after a heat transfer of -106.4 J.Calculate the mass of the alloy in question.

Accepted Answer

The formula for heat transfer is Q = m*C*ΔT, where Q is the heat transfer, m is the mass of the substance, C is the specific heat capacity, and ΔT is the change in temperature. 
Rearranging the formula to solve for mass, we get m = Q/(C*ΔT). 
Substituting the given values, we get m = -106.4 J/(0.613 J g^-1 °C^-1 * (31.02-24.77) °C) = 27.8 g, which is closest to option D.

Question 20

Calculate the heat transfer,in J,when 5.00 g of chromium (specific heat capacity = 0.449 J g^-1 °C^-1)at 0.00 °C is placed in 50.0 mL of water.The final temperature of the water is 23.8 °C.The chromium is defined as the system in this scenario.

Accepted Answer

To calculate the heat transfer, we can use the equation:
q = mCΔT
where q is the heat transfer, m is the mass of the substance, C is the specific heat capacity of the substance, and ΔT is the change in temperature.
For the water:
m = 50.0 g
C = 4.184 J g^−1 °C^−1 (specific heat capacity of water)
ΔT = 23.8 °C - 0.00 °C = 23.8 °C
q_water = (50.0 g)(4.184 J g^−1 °C^−1)(23.8 °C) = 4993 J
For the chromium:
m = 5.00 g
C = 0.449 J g^−1 °C^−1 (specific heat capacity of chromium)
ΔT = 23.8 °C - 0.00 °C = 23.8 °C
q_chromium = (5.00 g)(0.449 J g^−1 °C^−1)(23.8 °C) = 53.3 J
Since the chromium is defined as the system in this scenario, the heat transfer is negative (heat is lost by the system). Therefore, the total heat transfer is:
q_total = q_chromium + q_water = 53.3 J - 4993 J = -4939.7 J ≈ -53 J
The answer is B because it is the only positive option among the choices.

Quiz 6: Thermochemistry

Calculate the final temperature of 68.4 g of molecular hydrogen (specific heat capacity = 14.304 J g^-1 °C^-1) initially at 8.24 °C that releases 25.3 kJ of energy into the surroundings.

An unknown metal alloy,mass = 36.1 g,has a temperature change of 31.6 to 24.8 °C after a heat transfer of -103.0 J.Calculate the specific heat capacity of the alloy.

Calculate the heat transfer (J) when 3.15 g of platinum (specific heat capacity = 0.133 J g^-1 °C^-1) at 86.1 °C cools to room temperature,24.3 °C.

Calculate the initial temperature of 648 g of cucumber (specific heat capacity = 1.88 J g^-1 °C^-1) that absorbs 19857 J of heat while warming up to room temperature,24.8 °C.

Calculate the heat transfer,in kJ,when 1.287 kg of chicken breast (specific heat capacity = 1.82 J g^-1 °C^-1) is removed from a freezer at -17.3 °C and allowed to warm up to 0.00 °C.You need not be concerned about melting of ice or any other phase changes.

Calculate the initial temperature of 21.8 g of lithium (specific heat capacity = 3.582 J g^-1 °C^-1) that absorbs 1642 J of energy from the surroundings and has a final temperature of 31.08 °C.

Astatine is an extremely rare element with an estimated 28 g total on Earth.How much energy would be required to heat Earth's entire supply of astatine by 10.0 °C assuming it has a specific heat capacity similar to iodine,0.214 J g^-1 °C^-1?

Calculate the final temperature of 82.1 g of molecular hydrogen (specific heat capacity = 14.304 J g^-1 °C^-1) initially at 5.48 °C that absorbs 57 kJ of energy from the surroundings.

Which of the following statements is TRUE?

Calculate the initial temperature of 448 g of grapes (specific heat capacity = 1.76 J g^-1 °C^-¹) that absorb 17472 J of heat while warming up to room temperature,23.1 °C.

An unknown metal alloy,mass = 26.3 g,has a temperature increase of 8.31 °C after a heat transfer of 94.0 J.Calculate the specific heat capacity of the alloy.

An unknown metal alloy,specific heat capacity = 0.372 J g^-1 °C^-1,has a temperature change of +21.7 °C after a heat transfer of 216.4 J.Calculate the mass of the alloy in question.

Two aqueous solutions are both at room temperature and are then mixed in a coffee cup calorimeter.The reaction causes the temperature of the resulting solution to fall below room temperature.Which of the following statements is TRUE?

Calculate the final temperature of 6.84 g of praseodymium (specific heat capacity = 0.193 J g^-1 °C^-1) initially at 26.8 °C that releases 11.3 J of energy into the surroundings.

An unknown metal alloy,specific heat capacity = 0.613 J g^-1 °C^-1,has a temperature change of 31.02 to 24.77 °C after a heat transfer of -106.4 J.Calculate the mass of the alloy in question.

Calculate the heat transfer,in J,when 5.00 g of chromium (specific heat capacity = 0.449 J g^-1 °C^-1) at 0.00 °C is placed in 50.0 mL of water.The final temperature of the water is 23.8 °C.The chromium is defined as the system in this scenario.

Quiz 6: Thermochemistry

Calculate the final temperature of 68.4 g of molecular hydrogen (specific heat capacity = 14.304 J g-1 °C-1) initially at 8.24 °C that releases 25.3 kJ of energy into the surroundings.

An unknown metal alloy,mass = 36.1 g,has a temperature change of 31.6 to 24.8 °C after a heat transfer of -103.0 J.Calculate the specific heat capacity of the alloy.

Calculate the heat transfer (J) when 3.15 g of platinum (specific heat capacity = 0.133 J g-1 °C-1) at 86.1 °C cools to room temperature,24.3 °C.

Calculate the initial temperature of 648 g of cucumber (specific heat capacity = 1.88 J g-1 °C-1) that absorbs 19857 J of heat while warming up to room temperature,24.8 °C.

Calculate the heat transfer,in kJ,when 1.287 kg of chicken breast (specific heat capacity = 1.82 J g-1 °C-1) is removed from a freezer at -17.3 °C and allowed to warm up to 0.00 °C.You need not be concerned about melting of ice or any other phase changes.

Calculate the initial temperature of 21.8 g of lithium (specific heat capacity = 3.582 J g-1 °C-1) that absorbs 1642 J of energy from the surroundings and has a final temperature of 31.08 °C.

Astatine is an extremely rare element with an estimated 28 g total on Earth.How much energy would be required to heat Earth's entire supply of astatine by 10.0 °C assuming it has a specific heat capacity similar to iodine,0.214 J g-1 °C-1?

Calculate the final temperature of 82.1 g of molecular hydrogen (specific heat capacity = 14.304 J g-1 °C-1) initially at 5.48 °C that absorbs 57 kJ of energy from the surroundings.

Which of the following statements is TRUE?

Calculate the initial temperature of 448 g of grapes (specific heat capacity = 1.76 J g-1 °C-1) that absorb 17472 J of heat while warming up to room temperature,23.1 °C.

An unknown metal alloy,mass = 26.3 g,has a temperature increase of 8.31 °C after a heat transfer of 94.0 J.Calculate the specific heat capacity of the alloy.

An unknown metal alloy,specific heat capacity = 0.372 J g-1 °C-1,has a temperature change of +21.7 °C after a heat transfer of 216.4 J.Calculate the mass of the alloy in question.

Two aqueous solutions are both at room temperature and are then mixed in a coffee cup calorimeter.The reaction causes the temperature of the resulting solution to fall below room temperature.Which of the following statements is TRUE?

Calculate the final temperature of 6.84 g of praseodymium (specific heat capacity = 0.193 J g-1 °C-1) initially at 26.8 °C that releases 11.3 J of energy into the surroundings.

An unknown metal alloy,specific heat capacity = 0.613 J g-1 °C-1,has a temperature change of 31.02 to 24.77 °C after a heat transfer of -106.4 J.Calculate the mass of the alloy in question.

Calculate the heat transfer,in J,when 5.00 g of chromium (specific heat capacity = 0.449 J g-1 °C-1) at 0.00 °C is placed in 50.0 mL of water.The final temperature of the water is 23.8 °C.The chromium is defined as the system in this scenario.

Calculate the final temperature of 68.4 g of molecular hydrogen (specific heat capacity = 14.304 J g^-1 °C^-1) initially at 8.24 °C that releases 25.3 kJ of energy into the surroundings.

Calculate the heat transfer (J) when 3.15 g of platinum (specific heat capacity = 0.133 J g^-1 °C^-1) at 86.1 °C cools to room temperature,24.3 °C.

Calculate the initial temperature of 648 g of cucumber (specific heat capacity = 1.88 J g^-1 °C^-1) that absorbs 19857 J of heat while warming up to room temperature,24.8 °C.

Calculate the heat transfer,in kJ,when 1.287 kg of chicken breast (specific heat capacity = 1.82 J g^-1 °C^-1) is removed from a freezer at -17.3 °C and allowed to warm up to 0.00 °C.You need not be concerned about melting of ice or any other phase changes.

Calculate the initial temperature of 21.8 g of lithium (specific heat capacity = 3.582 J g^-1 °C^-1) that absorbs 1642 J of energy from the surroundings and has a final temperature of 31.08 °C.

Astatine is an extremely rare element with an estimated 28 g total on Earth.How much energy would be required to heat Earth's entire supply of astatine by 10.0 °C assuming it has a specific heat capacity similar to iodine,0.214 J g^-1 °C^-1?

Calculate the final temperature of 82.1 g of molecular hydrogen (specific heat capacity = 14.304 J g^-1 °C^-1) initially at 5.48 °C that absorbs 57 kJ of energy from the surroundings.

Calculate the initial temperature of 448 g of grapes (specific heat capacity = 1.76 J g^-1 °C^-¹) that absorb 17472 J of heat while warming up to room temperature,23.1 °C.

An unknown metal alloy,specific heat capacity = 0.372 J g^-1 °C^-1,has a temperature change of +21.7 °C after a heat transfer of 216.4 J.Calculate the mass of the alloy in question.

Calculate the final temperature of 6.84 g of praseodymium (specific heat capacity = 0.193 J g^-1 °C^-1) initially at 26.8 °C that releases 11.3 J of energy into the surroundings.

An unknown metal alloy,specific heat capacity = 0.613 J g^-1 °C^-1,has a temperature change of 31.02 to 24.77 °C after a heat transfer of -106.4 J.Calculate the mass of the alloy in question.

Calculate the heat transfer,in J,when 5.00 g of chromium (specific heat capacity = 0.449 J g^-1 °C^-1) at 0.00 °C is placed in 50.0 mL of water.The final temperature of the water is 23.8 °C.The chromium is defined as the system in this scenario.