Temperature and Heat Flashcards
Quantitative measure of hotness or coldness of a body
temperature
How does thermometer work
- The thermometer is placed in contact with the body
- The thermometer becomes hotter, the body cools off a little
- Thermal equilibrium
“If a system C is initially in thermal
equilibrium with both systems A and B, then A and B are also in thermal equilibrium with each other”
Zeroth Law of Dynamics
Two systems are in thermal equilibrium if and only if they have the same ___________.
temperature
The Measure of the average kinetic energy of all the particles in the object
temperature
The ______ and ______
determine the temperature
of the object
atoms mass and speed
Celsius (°C)
Boiling point of water
increments
Freezing Point of Water
Absolute Zero
100 °C
100
0°C
-273.15 °C
Fahrenheit (°F)
Boiling point of water
increments
Freezing Point of Water
Absolute Zero
212 °F
180
32 °F
-459.67 °F
Kelvin (K)
Boiling point of water
increments
Freezing Point of Water
Absolute Zero
373.15 K
100
273.15 K
0 K
Rankine (°R)
Boiling point of water
increments
Freezing Point of Water
Absolute Zero
671.64 °R
180
491.67 °R
0 °R
Change in physical dimensions
when subjected to change in temperature
thermal expansion
Most materials expand when __________
heated
The thermometer can measure
temperature because
the substance of the liquid inside
always expands (increases) or
contracts (decreases) by a certain
amount due to a change in temperature
is a strip that consists of two strips of different metals which expand at different rates as they are heated
is used to convert a temperature change into mechanical displacement.
Bimetallic strip
is defined as the transfer of energy across the boundary of a system due to a temperature difference between the system and its surroundings.
Heat
energy transfer that takes place solely because of a temperature difference
Heat flow/ heat transfer
Heat is measured by the units of
calorie and joule(J).
The amount of energy needed to raise thetemperatureof1gram of water by 1Co (from 14.5oC to 15.5oC)
calorie
1 calorie= _______ J
4.186
the amount of energy required to raise the temperature of 1lb of water by 1Fo (from63oF to 64oF)
British thermal unit (Btu)
1 Btu = _______ kcal = J
0.252
1055
The _______ of a particular sample of substance is defined as the amount of energy needed to raise the temperature of that by 1°C.
heat capacity C
The ___________ of a substance is the heat capacity per unit mass.
a measure of how thermally insensitive a substance is to the addition of energy
specific heat capacity c
the ___________ the material’s specific heat, the more energy must be added to a given mass of the material to cause a particular temperature change
greater
Energy that can be transferred from one body to another due to
temperature difference
The object with bigger c has ______ change in temperature compared to an object with smaller c
less
The value of the specific heat of a gas depends on whether the ____________ is held constant.
This distinction is not important for solids.
pressure or volume
Gases: Specific heat depends on the process because gases can expand and do work on their surroundings. 𝑐𝑝 > 𝑐𝑣
Solids: Expansion is negligible, so the distinction between constant pressure and constant volume is not important. Only one specific heat value is typically used.
- is the science of measuring changes in parameters
- of chemical reactions, physical changes, and phase transitions
- for the purpose of deriving the heat associated with those changes.
calorimetry
is any object or set of objects that we wish to consider
SYSTEM
- No mass enters or leaves but energy can be exchanged with the environment.
- ________ - if no energy in any form passes across its boundaries
Closed system
Isolated
Mass may enter or leave as may energy
Open system
If there is no heat loss to the surroundings, the heat lost by the hotter object equals the heat gained by the cooler ones
Conservation of energy
heat lost = heat gained
transition from one phase (solid, liquid, gas) to another.
Phase change
During a ___________, the temperature of the mixture does not change (provided the system is in thermal equilibrium).
When we add heat to ice at 0⁰C at normal atmospheric pressure, the temperature of the ice does not increase. Instead, some of it melts to form liquid water.
The effect of adding heat to this system is not to raise its temperature but to change its _________ (solid-liquid)
phase change
phase (solid-liquid)
_________ - transition between states of matter
- it requires transfer of ________
Phase change
energy
required heat for transition between solid and liquid states
Latent Heat of Fusion, Lf
(to fuse means “to combine by melting”)
water Lf
3.34 x 10^5 J/kg
Required heat for transition between liquid and gas states
Latent Heat of Vaporization, Lv
(the liquid “vaporizes”)
water Lv
2.256 x10^6 J/kg
