Heat and temperature

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# Heat and temperature - PowerPoint PPT Presentation

Heat and temperature. April. Vocab for review. Celsius condensation conduction convection energy transfer evaporation freezing gas heat joules Kelvin kinetic energy law of conservation of energy liquid melting molecular level

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## PowerPoint Slideshow about 'Heat and temperature' - thane-wong

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### Heat and temperature

April

Vocabfor review

Celsius condensation

conduction convection

energy transfer evaporation

freezing gas

heat joules

Kelvin kinetic energy

law of conservation of energy liquid

melting molecular level

phase phase change

potential energy pressure

specific heat sublimation

temperature thermal energy

work

Vocab for mastery

law of entropy

thermal equilibrium

thermodynamics

closed system

co-efficient

component

contraction

decay

deterioration

disorder

efficient

expansion

macroscopic

medium / media

relate directly

Engagement

*

http://jersey.uoregon.edu/vlab/Thermodynamics/index.html

*Thermal equilibrium: the state in which two bodies in physical contact with each other have identical temperatures.

EXPLORATION
• Virtual Lab – Determination of Specific Heat
• The amount of heat required to raise the temperature of a solid body depends on its change in temperature (DeltaT), its mass (m), and an intrinsic characteristic of the material forming the body called specific heat (cp). The heat is calculated from the equation
• q = cp x m x ΔT

Historically, heat (q) was measured in terms of calories. The calorie was defined as the amount of heat required to raise the temperature of 1 gram of water by 1 ⁰C from 14.5 ⁰C to 15.5 ⁰C at 1 atmosphere pressure. With this definition, the specific heat of water is 1.00 cal/(g · ⁰C ). The use of the calorie began before it was established that heat is a form of energy and 1 calorie is equivalent to 4.18 J. The joule (J) has become the more favored unit in recent years. Thus, the units for cp that we will use are J/(g · ⁰C ). The specific heat of water is then 4.18 J/(g · ⁰C ).

PURPOSE:

• To apply the experimental methods of calorimetry* in the determination of the specific heat of a metal.
• *calorimetry: an experimental procedure used to measure the energy transferred from one substance to another as heat.

PROCEDURE:

• Perform three trials for EACH material. Record the mass of the sample, the initial temperature (T1), the final temperature (T2), and the energy absorbed (in joules).
• Vary the mass of the sample and the length of time heating for each trial with a given material. In other words, no two trials for a given material should use both the same mass and the same flame exposure times.
• At the end of each trial, hit the "Reset" button to prepare for the next trial.
• http://www.sciencegeek.net/VirtualLabs/SpecificHeatLab.html
RESULT
• Observation and data:
result
• CALCULATIONS: Show your work! You will repeat the calculations three times for each material you test.
• Calculate the temperature change, ΔT, (T2 - T1).
• Calculate the specific heat, Cp. Cp = q ÷ m ÷ ΔT
Temperature scales
• Celsius and Fahrenheit scales
• Tf=9/5 Tc + 32
• Celsius and Kelvin (or absolute) scales
• T= Tc + 273.15

Leg “A”: temp. of ice changes as energy is added.

• Leg “B”: temp. of ice does not change. Instead, the nature of the ice changes. The ice-and-water mixture remains at this temp. until all of the ice melts.
• Leg “C”: the water’s temp. increases as energy is added.
• Leg “E”: the steam’s temp. increases.
• During Leg “B” and Leg “D,” the energy added or removed changes the internal energy of the substance without changing its temp. These changes in matter are called phase changes.