Chapter 4 lesson 1-6

This is the ______ _______ _________ in action: not all the energy can be used. If all the energy I applied to the car could've been used, the car could've continued to use that______ _______ until I stopped it. However, we know that ________ is slowly lost over time and that causes the car to stop.

second law of thermodynamics kinetic energy energy

_______ __________ of __________ states that it is impossible to extract _______ from a hot reservoir and use it all to do _______ some must be exhausted into a cold reservoir

second law of thermodynamics heat work

The first law of thermodynamics or law of conservation of energy

states that energy can't be created or destroyed, but you can convert it from one form to another.

law of conservation of energy

states that in any chemical or physical process, energy is neither created nor destroyed.

second law of thermodynamics

states that not all energy can be used.

A solid changing straight into a gas is called ______

sublimation.

A higher ___________ means that the molecules are moving faster on average. If you heat up a material, the molecules move faster and, as a result, they take up more _________- they tend to move into areas that were previously empty. This causes the size of the object to _________.

temperature space increase

Whereas _______ is the average kinetic energy of the molecules, the ______ is related to the spacing (or potential energy) of the molecules. Molecules that are further apart have more potential energy.

temperature state

What does it mean when the enthalpy change for a reaction is negative? that the reaction won't take place that the reaction is exothermic that the reaction is endothermic that the reaction needed energy to get started that the reaction was spontaneous

that the reaction is exothermic

Enthalpy change is the total amount of energy in a system when energy is neither created nor destroyed when one or more substances are changed into one or more different substances. the amount of energy as heat that is lost or gained by a system a chemical reaction

the amount of energy as heat that is lost or gained by a system

An example of an exothermic reaction is: an instant cold pack evaporation of water the lighting of a match when two chemicals are added together the breaking of bonds

the lighting of a match

Convection

the movement of heat by actual motion of matter;

radiation

the transfer of energy with the help of electromagnetic waves.

Conduction

the transfer of heat energy by direct contact

The ____ _______ that comes out of the Carnot Cycle is the difference between the work done by the engine in stages 1 and 2 and the ___ ______ (or the energy wasted) by you in stages 3 and 4.

useful work work done

An endothermic reaction is: when energy is either created or destroyed when the system gains heat as the surroundings cool down. when one or more substances are changed into one or more different substances. when the reaction involves subatomic particles when the system loses heat as the surroundings heat up.

when the system gains heat as the surroundings cool down.

Stages 3 and 4 both involve you doing ______ _on the system; you are expending _____ to make this happen by pushing down on the piston.

work energy

Thermal expansion

...occurs when an object expands and becomes larger due to a change in the object's temperature.

A metal bar has an original length of 2 meters and an expansion coefficient of 0.01. If you heat it up from 27 degrees Celcius to 37 degrees Celcius, by how much will the length change? 0.02 meters 0.74 meters 0.2 meters 2 meters

0.2 meters DeltaL/L = alphaL * deltaT temperature 36 degree C- 27 degree C = 10 degree C L= 2 meters alphaL= expansion coefficient of 0.01. deltaT= 10 degree C DeltaL = alphaL * deltaT * L DeltaL = 0.01 * 10 degree C* 2 meters DeltaL =0.2 total length change in metal bar =2.2 meters

This includes the types of heat transfer

1. conduction 2 convection, 3 radiation 4 phase (or state) changes 5. the relationship between energy and work 6 heat engines 7 the laws of thermodynamics

Or, in other words, no process can be _____ efficient because ______ is always lost somewhere. The _____ ________ sets the upper limit for what is possible, for what the maximally-efficient engine would look like.

100% energy Carnot Cycle

So let's say a bridge has a length of 50 meters on a day where the temperature is 15 degrees Celsius, and the expansion coefficient of the bridge is 0.0005. How long will the bridge be on a day where the temperature is 35 degrees Celsius?

35 degree C - 15 degree C = 20 degree C DeltaL/L = alphaL * deltaT delta L= ? L= 50 meters alphaL=expansion coefficient of the bridge is 0.0005 deltaT= 20 DeltaL= L * alphaL * deltaT DeltaL= 50meter * 0.0005* 20 DeltaL= 0.5 Total length of the bridge = 50 + 0.5 Total length of the bridge = 50.5

A Carnot engine has a hot reservoir at a temperature of 2000 degrees Celsius, and a cold reservoir at a temperature of -50 degrees Celsius. What is the efficient of the Carnot engine? 2.5% 80% 111% 90% 97.5%

90% T Kelvin= T Celsuis +273 Thot-> 2000 C-> 2273 K Tcold-> -50 C-> 223 K Carnot Efficiency = THot - TCold /Thot *100 =(2273 K- 223 K/ 2273 K)*100 90%

What is a heat engine? Any engine that produces motion. A device that produces heat from motion, and includes gasoline engines and steam engines. A device that produces heat from motion, and includes a bicycle. A device that produces motion from heat, and includes gasoline engines and steam engines. A device that produces motion from heat, and includes a bicycle.

A device that produces motion from heat, and includes gasoline engines and steam engines.

Which of the following is the best definition of thermal expansion? Molecules moving faster An object decreasing in size due to increased temperature An object increasing in size due to increased temperature An object never changing in size

An object increasing in size due to increased temperature

Why do bridges need expansion joints? Because bridges move around in the wind, and without expansion joints, they might collapse Expansion joints aren't actually necessary. Because the bridge might need to be extended one day Because bridges will expand and contract as temperature changes, and without expansion joints, they might collapse

Because bridges will expand and contract as temperature changes, and without expansion joints, they might collapse

Why does running a jar under hot water make it easier to open? Because the metal expands into the spaces between the glass threads Because hot things are more malleable Because the gaps between the threads and the lid get larger as it expands It doesn't.

Because the gaps between the threads and the lid get larger as it expands

Why is the zeroth law of thermodynamics important or necessary? Because you have to first define your terms, in particular: temperature. Because you have to first define your terms, in particular: pressure. It isn't important or necessary, because it's too obvious. Because you have to first define your terms, in particular: volume. Because you have to understand what thermal equilibrium is.

Because you have to first define your terms, in particular: temperature.

What does the linear coefficient of thermal expansion refer to? A number that can refer to how glass expands Both answers are correct. A number that can refer to how much metals expand Neither answer is correct.

Both answers are correct.

What is Carnot Efficiency Formula?

Carnot Efficiency = N_C = T_hot- T_cold / T_hot where TH is the temperature of the hot reservoir in Kelvin, and TC is the temperature of the cold reservoir in Kelvin: Carnot equation So, all you do is take the difference in temperature between the reservoirs, divide it by the temperature of the hot reservoir, and then multiply it by 100 to turn it into a percentage.

_______ represents How heat travels between objects in direct contact.

Conduction

_______ represents How heat passes through fluids.

Convection

Linear thermal expansion

DeltaL = L * alpha * deltaT DeltaL -> change in length L -> original length deltaT-> change in temperature L * alpha -> linear coefficient of linear thermal expansion

When energy is unavailable to be used it is called _____. Lost energy Entropy Wasted energy Enthalpy

Entropy

second law of thermodynamics

Every energy transfer or transformation increases the entropy of the universe.

The second law of thermodynamics states that: I. Energy can neither be created nor destroyed II. All free energy cannot be converted into usable energy III. The entropy of a system increases over time II and III II I III I and II

II and 111

What is the zeroth law of thermodynamics? If system (or object) A is in thermal equilibrium with system (or object) B, and is also in thermal equilibrium with system (or object) C, then B and C must also be in thermal equilibrium with each other. If system (or object) A has the same volume as system (or object) B, and also has the same volume as system (or object) C, then B and C must also have the same volume. If system (or object) A has the same pressure as system (or object) B, and also has the same pressure as system (or object) C, then B and C must also have the same pressure. If system (or object) A is in thermal equilibrium with system (or object) B, and is also in thermal equilibrium with system (or object) C, then B and C may or may not be in thermal equilibrium with each other. If system (or object) A is in thermal equilibrium with system (or object) B, and is also in thermal equilibrium with system (or object) C, then B and C must NOT be in thermal equilibrium with each other.

If system (or object) A is in thermal equilibrium with system (or object) B, and is also in thermal equilibrium with system (or object) C, then B and C must also be in thermal equilibrium with each other.

It's important to note that the temperatures must be in _______ for it to work. So, if you have a temperature in degrees ______ for example, you need to add 273 to that value to convert into Kelvin.

Kelvin Celsius

When something is moving it has _____ energy. High No Kinetic Potential

Kinetic

What are the laws of thermodynamics? Laws that govern the stationary heat energy. Laws that describe how objects move. Laws that describe nature as a whole. Laws that govern the movement of heat -- why and how it moves. Laws that describe how molecules are distributed statistically.

Laws that govern the movement of heat -- why and how it moves.

Which phase (or state) has molecules that can slide past each other, but always have the same volume? Liquids Gases Solids Bose-Einstein Condensate Plasma

Liquids

________ on the other hand are substances with molecules that can slide past one another and aren't as tightly packed as _________. Liquids do not have a consistent ________, and will change _______ to fill the container.

Liquids solids shape shape

If object A has a temperature of 50 degrees Celsius, and object A is in thermal equilibrium with objects B and C, which of the following statements can NOT be concluded from the zeroth law of thermodynamics? The temperature of object A is 50 degrees Celsius. Objects B and C are in thermal equilibrium with each other. Objects B and C have the same heat content. The temperature of object C is 50 degrees Celsius. The temperature of object B is 50 degrees Celsius.

Objects B and C have the same heat content.

_______ represents How heat flows through empty spaces.

Radiation

________ are substances with tightly-packed molecules in neat rows that can only move by vibrating.

Solids

During which stages of the Carnot Cycle is useful work extracted? Stages 2 and 4 (adiabatic expansion, and adiabatic contraction). Stages 3 and 4 (isothermal contraction, and adiabatic contraction). Stages 1 and 3 (isothermal expansion, and isothermal contraction). Stages 1 and 4 (isothermal expansion, and adiabatic contraction). Stages 1 and 2 (isothermal expansion, and adiabatic expansion).

Stages 1 and 2 (isothermal expansion, and adiabatic expansion).

During which stages of the Carnot Cycle is work done on the system (lost energy)? Stages 1 and 3 (isothermal expansion, and isothermal contraction). Stages 1 and 2 (isothermal expansion, and adiabatic expansion). Stages 1 and 4 (isothermal expansion, and adiabatic contraction). Stages 3 and 4 (isothermal contraction, and adiabatic contraction). Stages 2 and 4 (adiabatic expansion, and adiabatic contraction).

Stages 3 and 4 (isothermal contraction, and adiabatic contraction).

Which of the following is not an example of a phase change? Sublimation Freezing Condensing Sweating Boiling

Sweating

Let's say you are operating a Carnot engine with a hot reservoir at a temperature of 100 degrees Celsius and a cold reservoir at a temperature of 0 degrees Celsius. What is the efficiency of the Carnot engine?

T Kelvin= T Celsuis +273 Thot-> 100 C-> 373 K Tcold->0 C-> 273 K Carnot Efficiency = THot - TCold /Thot *100 = 373K - 273K / 373K * 100 = 100/ 373 *100 = 27 %

How are temperature and phase different in terms of molecules? Temperature is a larger increase in the kinetic energy of molecules than phase. Temperature is the average movement energy of molecules, whereas phase is related to how much the molecules stick to each other. Phase is the average movement energy of molecules, whereas temperature is related to the potential energy (position) of molecules. Temperature is the average movement energy of molecules, whereas phase is related to the potential energy (position) of molecules. Temperature is a smaller increase in the kinetic energy of molecules than phase.

Temperature is the average movement energy of molecules, whereas phase is related to the potential energy (position) of molecules.

The fact that energy can be neither created nor destroyed is _____. Newton's First Law of Motion Einstein's Law The First Law of Thermodynamics Not true

The First Law of Thermodynamics

Which of the following concepts best describes a chlorophyll molecule absorbing light and changing it into chemical energy? Boyle's Law The Second Law of Thermodynamics Newton's Third Law of Motion Bernoulli's Principle The Law of Conservation of Energy

The Law of Conservation of Energy

What is thermal energy? The energy of a substance or system in terms of the pressure of its molecules. The energy of a gas. The energy of a substance or system in terms of the potential energy of its molecules. The energy of a substance or system as a whole object. The energy of a substance or system in terms of the motion or vibrations of its molecules.

The energy of a substance or system in terms of the motion or vibrations of its molecules.

What is the Carnot Cycle? The least efficient possible heat engine, involving two isothermal processes and two adiabatic processes. The most efficient possible heat engine, involving two isothermal processes and two isobaric processes. The most efficient possible heat engine, involving two isobaric processes and two adiabatic processes. The most efficient possible heat engine, involving two isothermal processes and two adiabatic processes. The most efficient possible heat engine, involving three isothermal processes and two adiabatic processes.

The most efficient possible heat engine, involving two isothermal processes and two adiabatic processes.

heat transfer

The movement of energy from hot object to colder object through collisions and movements of molecules, .

What is heat transfer? The movement of energy through collisions and movements of molecules, from cold places to hot places. The movement of energy through collisions and movements of molecules, from hot places to other hot places. The movement of energy through collisions and movements of molecules, from hot places to cold places. The movement of energy through two objects colliding. The movement of energy through electrical generation.

The movement of energy through collisions and movements of molecules, from hot places to cold places.

What is thermodynamics? The study of temperature. The study of the movement of heat energy. The study of stationary heat energy. The study of superheroes. The study of heat engines.

The study of the movement of heat energy.

Entropy

a measure of molecular randomness or disorder of a system

heat content

a thermodynamic quantity equal to the internal energy of a system plus the product of its volume and pressure

Lastly, stage 4 is an _______ _________-, where you remove the _____ reservoir. The volume continues to ______ but without the cold reservoir, this leads to both the pressure and temperature _________.

adiabatic compression cold decrease increasing

Stage 2 is an ________ _________ , where the hot reservoir is now taken away. The gas continues to _______, causing the pressure and temperature to ________. Stages 1 and 2 are where the engine actually does useful ________.

adiabatic expansion expand decrease work

When a bond forms, energy is given off to the surroundings. This is an example of an exothermic reaction an endothermic reaction the law of conservation of matter. Newton's third law.

an exothermic reaction

An open system

can exchange energy and matter.

An isolated system

cannot exchange any heat, work, or matter with the surroundings

To know for certain that a reaction has happened, you need to have evidence that a substance has _______ __________.

changed identity.

A ______ system has boundaries which are completely closed.

closed system

A ______ system mass will remain constant with time

closed system

Energy in a closed system

closed system can exchange energy (as heat or work) but not matter, with its surroundings.

This is where heat enters the system from the hot reservoir (i.e., from your power source) to keep the temperature ________. The gas inside the engine is allowed to naturally ______ and _____ a piston.

constant expand push

a gas changing straight into a solid is called _______.

deposition.

Carnot Cycle

describes the most efficient possible heat engine, involving two isothermal processes and two adiabatic processes.

An __________ reaction is the opposite. This is when a reaction starts colder and ends up hotter, taking in energy from start to finish.

endothermic

___________ reaction, the system gains heat as the surroundings cool down.

endothermic

At the molecular level, an __________ reaction is when a bond is formed. When two things come together, they're happier and take less energy to stay together.

exothermic

In an __________ reaction, the system loses heat as the surroundings heat up.

exothermic

means that during the reaction, molecules have moved from a higher state of energy to a lower state.

exothermic reaction

If heat is given off, the reaction is___________

exothermic.

Bridges are built out of concrete and other relatively firm materials, but these materials ______ just like anything else. When that happens, a bridge could break and collapse. To avoid this, expansion joints are placed on large bridges. That way, as the temperature varies over the course of the year, the bridge is free to get longer or shorter, without causing cracks or breakages.

expand

So when you heat up the jar lid, the same thing happens - the jar lid __________. So does the _______, but ________ expand more than glass. The gaps between the metal jar lid and the glass threads __________, so it becomes easier to open.

expands glass metals increase

The coefficient is just a number that represents how much the material _________. Metals, for example, tend to expand more than _______.

expands plastics

And ________ are substances with molecules that are free to move in every direction. With a ____, not only does it not have a consistent ________, but it doesn't even have a consistent _______- the space it takes up can change.

gases gas shape volume

We can plot a graph to show the energy involved in phase changes: a graph of temperature plotted against______ added. It looks like this. As you can see, there are diagonal areas and flat areas. The diagonal areas are where _______ is being added to increase the temperature. The flat areas are the phase changes, where heat is being added, but is going into the ______ _______ of the molecules, not the kinetic energy - the temperature therefore remains the same during these phase changes. These graphs and the equations that go with them are discussed in more detail in another lesson.

heat heat potential energy

If two substances combine and ______ & _______ are produced, this is strong evidence that a reaction has taken place.

heat and light

The faster the molecules in a substance move, the more ____ ______ they have.

heat energy

And _________ __________includes gasoline engines and steam engines.

heat engine

For example, if you were to put your warm hands against a cold metal pole, the skin on your hands would feel cold. That's because the heat from your hands transfers to the cooler metal. Your hands feel colder because some of your heat has been transferred to the metal.

heat transfer

You can transfer heat energy from one object to another, and in fact, a ______ ______ will occur naturally whenever a hotter object is in contact with a colder one; heat will always move from the ________ object to the _______ one.

heat transfer hotter colder

A heat engine

is a device that produces motion from heat

Enthalpy

is a measure of the total system of energy of a thermodynamic system. It includes the internal energy, which is the required to create a system.

An adiabatic process

is a process where no heat enters or leaves the system to or from a reservoir and the temperature, pressure, and volume are all free to change, relative to each other.

isothermic process

is a process where the temperature remains constant and the volume and pressure vary relative to each other.

Enthalpy change

is the amount of energy as heat that is lost or gained by a system.

Temperature

is the average kinetic (or movement) energy of the molecules in a substance.

Temperature

is the average kinetic energy of the molecules in a substance

Heat energy, or thermal energy

is the energy of a substance or system in terms of the motion or vibrations of its molecules.

Thermodynamics

is the study of the movement of heat energy.

chemical reaction

is when one or more substances are changed into one or more different substances.

Thermal equilibrium

is when two systems or objects have no flow of heat between them despite being connected by a path permeable to heat. permeable (allowing liquid or gas to pass through

Stage 3 is an ________ ____________, where the volume _________ and the pressure _______ at a constant _________. The temperature is kept constant by putting it in contact with a _____ reservoir. Here, you actually have to do ______ by physically pushing the piston to compress the gas.

isothermal compression decreases increases temperature cold work

Stage 1 is an _____ __________, where the ______- increases and the ______decreases at a constant temperature.

isothermal expansion volume pressure

The numbers represent the strength of a chemical bond. They are usually measured in .....

kcal/mole or kJ/mole.

When I pushed the car, I infused that car with _____ ______. Those rubber tires started to move and continued to move down the street. However, the rubber of the tire is scraping against the pavement. As it scrapes against the pavement, it's going to produce______ due to the ________. Heat is another form of ________, but heat isn't ____ ________.

kinetic energy heat friction energy kinetic energy

example of ______ of _______ of _________ What this means is that if energy of the system decreases, then the energy of the surroundings _________ by the same amount

law of conservation of energy increases

enthalpy is the amount of energy in a system capable of doing _____ _______-" enthalpy, total __________, H.

mechanical work heat

Every phase change has a name: changing a solid to a liquid is called _________, changing a liquid to a gas is called __________ (or _________) , changing a gas to a liquid is called _____________. changing a liquid to a solid is called ________.

melting boiling evaporating/ condensing freezing

spontaneous

not requiring an outside source of energy to proceed

A ______ system has boundaries which are not closed.

open system

A ______ system mass will vary with time

open system

Molecules that are further apart have more _____ _______.

potential energy.

The Carnot Cycle can be described by this ______-_______ graph

pressure-volume graph:

zeroth law of thermodynamics

says that if system (or object) A is in thermal equilibrium with system (or object) B, and is also in thermal equilibrium with system (or object) C, then B and C must also be in thermal equilibrium with each other.