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ssm Ideally, when a thermometer is used to measure the temperature of an object, the temperature of the object itself should not change. However, if a significant amount of heat flows from the object to the thermometer, the temperature will change. A thermometer has a mass of 31.0 g, a specific heat capacity of \(c=815 {J} /({kg} \cdot {C}^{\circ})\) \(c=815 {J} /({kg} \cdot {C}^{2})\) and a temperature of \(12.0^{\circ} {C}\) . It is immersed in 119 g of water, and the final temperature of the water and thermometer is \(41.5^{\circ} {C}\) . What was the temperature of the water before the insertion of the thermometer?

Short Answer

Expert verified
The initial temperature of the water was approximately \(39.99^{\circ} \text{C}\).

Step by step solution

01

Convert Mass to Kilograms

The mass of the thermometer is given as 31.0 grams. To perform calculations using the specific heat capacity in SI units, convert this mass to kilograms by dividing by 1000.\[m_{t} = \frac{31.0}{1000} = 0.031 \text{ kg}\]
02

Apply the Principle of Heat Exchange

When the thermometer is immersed in water, the heat lost by the thermometer equals the heat gained by the water, assuming no heat loss to the surroundings. Use the formula:\[m_{t}c_{t}(T_f - T_i) = m_{w}c_{w}(T_i - T_f)\]where:- \(m_{t}\) is the mass of the thermometer- \(c_{t}\) is the specific heat capacity of the thermometer- \(T_f\) and \(T_i\) are the final and initial temperatures of the thermometer- \(m_{w}\) and \(c_{w}\) are the mass and specific heat capacity of water, respectively.Set the specific heat, \(c_{w} = 4186\, \text{J/(kg} \cdot \text{C)}\).
03

Calculate Heat Exchanged by Thermometer

Substitute the known values for the thermometer:\[Q_{t} = (0.031 \text{ kg})(815 \text{ J/kg} \cdot \text{C})(41.5^{\circ} \text{C} - 12.0^{\circ} \text{C})\]\[Q_{t} = (0.031)(815)(29.5) = 749.3175 \text{ J}\]
04

Apply Heat Exchange Formula to Water

The heat gained by the water, \(Q_w\), can be set equal to the heat lost by the thermometer:\[Q_w = m_{w}c_{w}(T_f - T_i)\]where we solve for \(T_i\): \[Q_w = 749.3175 \text{ J}\]\[119 \text{ g} = 0.119 \text{ kg}\]\[T_f = 41.5^{\circ} \text{C}\]Rearrange for \(T_i\):\[ T_i = T_f - \frac{Q_w}{m_{w}c_{w}}\]
05

Solve for the Initial Temperature of Water

Now substitute the values into the equation:\[T_i = 41.5 - \frac{749.3175}{(0.119)(4186)}\]\[T_i = 41.5 - 1.513 \]\[T_i \approx 39.987^{\circ} \text{C}\]

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Thermodynamics
At the heart of thermodynamics is the study of energy transformations in physical systems. It explores how energy is transferred and transformed, focusing on heat and work. Thermodynamics helps us understand the flow of energy within a system, which is crucial in predicting how substances will react and change over time.

In this exercise, thermodynamics principles explain how the thermometer and the water reach a thermal equilibrium. This happens when the heat lost by the thermometer equals the heat gained by the water. This exchange ensures energy conservation within the system. Thermodynamics is governed by laws that dictate these processes, ensuring energy is neither created nor destroyed but merely transferred or converted.
Specific Heat Capacity
Specific heat capacity is a specific property that tells us how much heat is needed to raise the temperature of a substance. It is defined as the amount of heat required to change the temperature of one kilogram of a substance by one degree Celsius (or Kelvin). This concept is particularly useful in thermodynamic processes like the one involving our thermometer.

In this scenario, the specific heat capacity of both the thermometer and water is used to understand how heat is transferred. The specific heat capacity of the thermometer is 815 J/(kg·°C), meaning it requires 815 joules to raise the temperature of one kilogram of the thermometer material by one degree Celsius. Meanwhile, water has a specific heat capacity of 4186 J/(kg·°C), illustrating its ability to absorb a significant amount of heat without a substantial change in temperature.

By applying this concept, you can accurately calculate how much energy is exchanged between the thermometer and water during the heat transfer process.
Temperature Measurement
Temperature measurement is a fundamental part of this exercise and of thermodynamic studies in general. It involves quantifying how hot or cold an object is, with the Celsius scale being widely used in scientific explorations and daily life.

Using a thermometer, one can determine the temperature of a system. The problem illustrates a real-world complication of temperature measurement, where the measuring device influences the system it intends to measure. The thermometer absorbs heat from the water, leading to a slight temperature change in the water before reaching the final equilibrium temperature of 41.5°C. This highlights the practical challenge that any assessing tool may affect the system, requiring compensation adjustments in calculations.

Correct measurement depends on minimizing the impact of the measuring device on the system or properly accounting for the interaction in the analysis.
Heat Exchange
Heat exchange refers to the transfer of thermal energy between two objects or systems. This concept is vital in understanding how temperature and energy interact in thermodynamics.

In our scenario, heat exchange occurs between the thermometer and the water. The thermometer, starting at 12°C, absorbs heat from the warmer water until both reach a common temperature of 41.5°C. This process is governed by the principle that the amount of heat lost by one body equals the amount of heat gained by another, assuming no loss to the external environment. This is often referred to as the principle of thermal equilibrium.

Key factors influencing heat exchange include the specific heat capacities of the involved substances and their masses. Accurate calculations require precise input values, as seen in the calculation of the initial water temperature before the immersion of the thermometer.

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Most popular questions from this chapter

Three portions of the same liquid are mixed in a container that prevents the exchange of heat with the environment. Portion A has a mass m and a temperature of \(94.0^{\circ} {C},\) portion \({B}\) also has a mass \(m\) but a temperature of \(78.0^{\circ} {C},\) and portion C has a mass \(m_{{C}}\) and a temperature of \(34.0^{\circ} {C}\) . What must be the mass of portion \({C}\) so that the final temperature \(T_{{f}}\) of the three-portion mixture is \(T_{t}=50.0^{\circ} {C} ?\) Express your answer in terms of \(m ;\) for example, \(m_{{C}}=2.20 {m} .\)

SSM Suppose you are hiking down the Grand Canyon. At the top, the temperature early in the morning is a cool 3 C. By late afternoon, the temperature at the bottom of the canyon has warmed to a sweltering 34 C. What is the difference between the higher and lower temperatures in (a) Fahrenheit degrees and (b) kelvins?

ssm Multiple-Concept Example 11 uses the same physics principles as those employed in this problem. A block of material has a mass of 130 \({kg}\) and a volume of \(4.6 \times 10^{-2} {m}^{3}\) . The material has a specific heat capacity and coefficient of volume expansion, respectively, of 750 \({J} / {kg} \cdot {C}^{9}\) and \(6.4 \times 10^{-5}({C}^{0})^{-1}\) . How much heat must be added to the block in order to increase its volume by \(1.2 \times 10^{-5} {m}^{3} ?\)

ssm At a fabrication plant, a hot metal forging has a mass of 75 \({kg}\) and a specific heat capacity of 430 \({J} / {kg} \cdot {C}^{\circ}\) . To harden it, the forging is immersed in 710 \({kg}\) of oil that has a temperature of \(32^{\circ} {C}\) and a specific heat capacity of 2700 \({J} / {kg} \cdot {C}^{\circ}\) ). The final temperature of the oil and forging at thermal equilibrium is \(47^{\circ} {C}\) . Assuming that heat flows only between the forging and the oil, determine the initial temperature of the forging.

You are sick, and your temperature is 312.0 kelvins. Convert this temperature to the Fahrenheit scale.

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