Textbook Question
Sodium metal is sometimes used as a cooling agent in heat-exchange units because of its releatively high molar heat capacity fo 28.2 J/(mol·°C). What is the specific heat and molar heat capacity of sodium in J/g·°C?
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Ch.9 - Thermochemistry: Chemical Energy
Chapter 9, Problem 81
Calculate the amount of heat required to raise the tempera- ture of 250.0 g (approximately 1 cup) of hot chocolate from 25.0 °C to 80.0 °C. Assume hot chocolate has the same spe-cific heat as water 34.18 J>1g °C24.
Verified step by step guidance1
Step 1: Identify the given values. The mass (m) of the hot chocolate is 250.0 g, the initial temperature (T1) is 25.0 °C, the final temperature (T2) is 80.0 °C, and the specific heat (c) is 4.18 J/g°C.
Step 2: Understand the formula to calculate heat (q), which is q = mcΔT, where ΔT is the change in temperature.
Step 3: Calculate the change in temperature (ΔT) by subtracting the initial temperature from the final temperature. ΔT = T2 - T1.
Step 4: Substitute the given values into the formula. q = (250.0 g) * (4.18 J/g°C) * (ΔT °C).
Step 5: Solve the equation to find the amount of heat required. Remember, the unit of the final answer should be in Joules (J).
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Specific Heat Capacity
Specific heat capacity is the amount of heat required to raise the temperature of one gram of a substance by one degree Celsius. It is a crucial property in thermodynamics, as it determines how much energy is needed to change the temperature of a material. For water, the specific heat capacity is approximately 4.18 J/g°C, which is used in this problem to calculate the heat required for the hot chocolate.
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02:19
Heat Capacity
Heat Transfer
Heat transfer refers to the movement of thermal energy from one object or substance to another due to a temperature difference. In this context, heat is transferred to the hot chocolate to increase its temperature from 25.0 °C to 80.0 °C. The amount of heat transferred can be calculated using the formula Q = mcΔT, where Q is the heat added, m is the mass, c is the specific heat capacity, and ΔT is the change in temperature.
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02:19Heat Capacity
Temperature Change
Temperature change is the difference between the initial and final temperatures of a substance. In this problem, the temperature change (ΔT) is calculated by subtracting the initial temperature (25.0 °C) from the final temperature (80.0 °C). Understanding how to calculate this change is essential for determining the total heat required to raise the temperature of the hot chocolate.
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02:03Temperature Conversion Formulas
Related Practice
Textbook Question
Titanium metal is used as a structural material in many high-tech applications, such as in jet engines. what is the specific heat of titanium in J/(g·°C) if it takes 89.7 J to raise the temeprature of a 33.0 g block of 5.20 °C? What is the molar heat capacity of titanium J/(mol·°C)?
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Textbook Question
Assuming that Coca-Cola has the saem specific heat as water [4.18 J/(g C)], calculate the amount of heat in kilojoules transferred when one can (about 350 g) is cooled from 25 C to 3 C.
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Textbook Question
Instant cold packs used to treat athletic injuries contain solid NH4NO3 and a pouch of water. When the pack is squeezed, the pouch breaks and the solid dissolves, lowering the tem-perature because of the endothermic reaction NH4NO31s2 ¡ NH4NO31aq2 ∆H = +25.7 kJ What is the final temperature in a squeezed cold pack that contains 50.0 g of NH4NO3 dissolved in 125 mL of water? Assume a specific heat of 4.18 J/(g C) for the solution, an initial temperature of 25.0 °C, and no heat transfer between the cold pack and the environment.
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Textbook Question
Instant hot packs contain a solid and a pouch of water. When the pack is squeezed, the pouch breaks and the solid dis- solves, increasing the temperature because of the exothermic reaciton. The following reaction is used to make a hot pack: H2O
LiCl1s2 ¡ Li 1aq2 + Cl 1aq2 ∆H = -36.9 kJ. What is the final temperature in a squeezed hot pack that contains 25.0 g of LiCl dissolved# in 125 mL of water? Assume a specific heat of 4.18 J>1g °C2 for the solution, an initial temperature of 25.0 °C, and no heat transfer between the hot pack and the environment.
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Textbook Question
When 0.187 g of benzene, C6H6, is burned in a bomb calorimeter the temperature rises by 3.45 °C. If the heat capacity of the calorimeter is 2.46 kJ>°C, calculate the combustion energy 1∆E2 for benzene in units of kJ/g and kJ/mol.
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