Textbook Question
The average human lung expands by about 0.50 L during each breath. If this expansion occurs against an external pressure of 1.0 atm, how much work (in J) is done during the expansion?
2037
views
Ch.7 - Thermochemistry
Tro6th EditionChemistry: A Molecular ApproachISBN: 9780137832217
Not the one you use?Change textbookSelect a different textbook
Table of contents
- Ch.1 - Matter, Measurement & Problem Solving90
- Ch.2 - Atoms & Elements94
- Ch.3 - Molecules and Compounds103
- Ch.4 - Chemical Reactions and Chemical Quantities46
- Ch.5 - Introduction to Solutions and Aqueous Solutions65
- Ch.6 - Gases100
- Ch.7 - Thermochemistry85
- Ch.8 - The Quantum-Mechanical Model of the Atom51
- Ch.9 - Periodic Properties of the Elements79
- Ch.10 - Chemical Bonding I: The Lewis Model70
- Ch.11 - Chemical Bonding II: Molecular Shapes, VSEPR & MO Theory68
- Ch.12 - Liquids, Solids & Intermolecular Forces44
- Ch.13 - Solids & Modern Materials42
- Ch.14 - Solutions77
- Ch.15 - Chemical Kinetics88
- Ch.16 - Chemical Equilibrium57
- Ch.17 - Acids and Bases121
- Ch.18 - Aqueous Ionic Equilibrium126
- Ch.19 - Free Energy & Thermodynamics80
- Ch.20 - Electrochemistry87
- Ch.21 - Radioactivity & Nuclear Chemistry61
- Ch.22 - Organic Chemistry114
Chapter 7, Problem 50
How much heat is required to warm 2.50 kg of sand from 25.0 °C to 100.0 °C?
Verified step by step guidance1
Identify the formula to calculate the heat required: \( q = m \cdot c \cdot \Delta T \), where \( q \) is the heat energy, \( m \) is the mass, \( c \) is the specific heat capacity, and \( \Delta T \) is the change in temperature.
Determine the mass \( m \) of the sand, which is given as 2.50 kg.
Find the specific heat capacity \( c \) of sand. For sand, \( c \) is approximately 0.84 J/g°C. Convert this to J/kg°C by multiplying by 1000, resulting in 840 J/kg°C.
Calculate the change in temperature \( \Delta T \) by subtracting the initial temperature from the final temperature: \( \Delta T = 100.0 \text{ °C} - 25.0 \text{ °C} \).
Substitute the values into the formula: \( q = 2.50 \text{ kg} \times 840 \text{ J/kg°C} \times \Delta T \) to find the heat required.
Verified video answer for a similar problem:
This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
1mWas this helpful?
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 kilogram of a substance by one degree Celsius. It is a material-specific property that varies between different substances. For sand, the specific heat capacity is approximately 0.84 J/g°C, which means it requires this amount of energy to increase its temperature.
Recommended video:
Guided course
02:19
Heat Capacity
Heat Transfer Equation
The heat transfer equation, often expressed as Q = mcΔT, relates the heat energy (Q) absorbed or released by a substance to its mass (m), specific heat capacity (c), and the change in temperature (ΔT). In this equation, ΔT is calculated as the final temperature minus the initial temperature. This formula is essential for calculating the heat required to change the temperature of a substance.
Recommended video:
Guided course
02:19Heat Capacity
Units of Measurement
Understanding units of measurement is crucial in chemistry calculations. Heat is typically measured in joules (J) or calories, while mass is measured in kilograms (kg) or grams (g). When using the specific heat capacity in calculations, it is important to ensure that all units are consistent, particularly when converting between kilograms and grams or between Celsius and Kelvin.
Recommended video:
Guided course
02:52Units of Radiation Measurement
Related Practice
Textbook Question
The air within a piston equipped with a cylinder absorbs 565 J of heat and expands from an initial volume of 0.10 L to a final volume of 0.85 L against an external pressure of 1.0 atm. What is the change in internal energy of the air within the piston?
3726
views
2
rank
Textbook Question
A kilogram of aluminum metal and a kilogram of water are each warmed to 75 °C and placed in two identical insulated containers. One hour later, the two containers are opened and the temperature of each substance is measured. The aluminum has cooled to 35 °C, while the water has cooled only to 66 °C. Explain this difference.
1214
views
Textbook Question
An unknown mass of each substance, initially at 23.0 °C, absorbs 1.95 × 103 J of heat. The final temperature is recorded. Find the mass of each substance.
a. Pyrex glass (Tf = 55.4°C)
b. sand (Tf = 62.1°C)
c. ethanol (Tf = 44.2°C)
d. water (Tf = 32.4°C)
1478
views
Textbook Question
We pack two identical coolers for a picnic, placing 24 12-ounce soft drinks and five pounds of ice in each. However, the drinks that we put into cooler A were refrigerated for several hours before they were packed in the cooler, while the drinks that we put into cooler B were at room temperature. When we open the two coolers three hours later, most of the ice in cooler A is still present, while nearly all of the ice in cooler B has melted. Explain this difference.
1120
views
Textbook Question
How much heat is required to warm 2.50 L of water from 25.0 °C to 100.0 °C? (Assume a density of 1.0 g/mL for the water.)
1
views