Search found 25 matches

by Amelia Georgius 1K
Wed Feb 07, 2018 5:35 pm
Forum: Phase Changes & Related Calculations
Topic: Endothermic/exothermic
Replies: 4
Views: 236

Re: Endothermic/exothermic

A process is exothermic when it releases heat and a process is endothermic when it absorbs heat.
by Amelia Georgius 1K
Wed Feb 07, 2018 5:31 pm
Forum: Calculating Work of Expansion
Topic: Work Equations [ENDORSED]
Replies: 9
Views: 267

Re: Work Equations [ENDORSED]

You can use the equation w= -PdeltaV when pressure is constant
You can use the equation w= -nRt lnV2/V1 when temperature is constant
by Amelia Georgius 1K
Wed Feb 07, 2018 5:29 pm
Forum: Calculating Work of Expansion
Topic: Integral [ENDORSED]
Replies: 4
Views: 130

Re: Integral [ENDORSED]

The integrals were used in lecture as a way to show how the different equations were derived
by Amelia Georgius 1K
Wed Feb 07, 2018 5:28 pm
Forum: Calculating Work of Expansion
Topic: Irreversible expansion
Replies: 4
Views: 113

Re: Irreversible expansion

When pressure is constant, you can use the equation w= -PdeltaV, but when temperature is constant, you can use the other equation, w= -nRT lnV2/V1.
by Amelia Georgius 1K
Wed Feb 07, 2018 5:23 pm
Forum: Calculating Work of Expansion
Topic: Diagram of Reversible Expansion
Replies: 3
Views: 120

Re: Diagram of Reversible Expansion

A vacuum is a space that does not have any matter in it, not even air. Space is a vacuum
by Amelia Georgius 1K
Wed Feb 07, 2018 5:19 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Reversible systems
Replies: 7
Views: 224

Re: Reversible systems

Because both volume and pressure are changing, you would need to use both Cv and Cp
by Amelia Georgius 1K
Mon Jan 22, 2018 9:07 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: PdeltaV=deltanRT
Replies: 4
Views: 448

Re: PdeltaV=deltanRT

Because w=PdeltaV, work could also be found using w=deltanRT when a value in the other equation is not known. This is because of the equation pV=nRT
by Amelia Georgius 1K
Mon Jan 22, 2018 9:04 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Open Beaker [ENDORSED]
Replies: 5
Views: 230

Re: Open Beaker [ENDORSED]

Because the system is open it can therefore remain at a constant pressure with its surroundings because it can exchange both energy and matter to come to an equilibrium pressure state.
by Amelia Georgius 1K
Mon Jan 22, 2018 9:02 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Calorimeter
Replies: 10
Views: 357

Re: Calorimeter

A calorimeter can measure energy that will be used in calculations.
by Amelia Georgius 1K
Mon Jan 22, 2018 9:01 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Adiabatic [ENDORSED]
Replies: 8
Views: 310

Re: Adiabatic [ENDORSED]

An adiabatic process is one in which there is no heat transfer between a system and its surroundings.
by Amelia Georgius 1K
Mon Jan 22, 2018 8:59 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Energy and matter?
Replies: 6
Views: 229

Re: Energy and matter?

yes, in an open system, both energy and matter can be exchanged between system and the surroundings. In a closed system, only energy can be exchanged. In an isolated system, neither energy nor matter can be exchanged between a system and its surroundings.
by Amelia Georgius 1K
Mon Jan 22, 2018 8:57 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Bomb calorimeter
Replies: 7
Views: 216

Re: Bomb calorimeter

A bomb calorimeter completely closes off its contents from the surroundings so that neither energy nor matter can be exchanged between the system and its surroundings, making it an isolated system.
by Amelia Georgius 1K
Mon Jan 22, 2018 8:56 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Difference between Closed and Isolated
Replies: 10
Views: 360

Re: Difference between Closed and Isolated

A closed system can exchange energy with its surroundings, an example would be a closed test tube. An isolated system cannot exchange energy or matter with its surroundings, such as an insulated thermos.
by Amelia Georgius 1K
Mon Jan 22, 2018 8:54 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Isolated vs Closed system
Replies: 3
Views: 136

Re: Isolated vs Closed system

An isolated system is completely closed off from its surroundings and cannot exchange matter or energy with its surroundings. A closed system is closed off from its surroundings and cannot exchange matter, but this system can exchange energy with its surroundings.
by Amelia Georgius 1K
Mon Jan 22, 2018 8:52 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: System Types
Replies: 7
Views: 196

Re: System Types

In an open system, both energy and matter can be exchanged between the system and the surroundings. In a closed system, only energy can be exchanged between the system and the surroundings, and in an isolated system neither energy or matter can be exchanged between the system and the surroundings.
by Amelia Georgius 1K
Sun Dec 03, 2017 10:39 pm
Forum: Lewis Structures
Topic: Central Atom? [ENDORSED]
Replies: 7
Views: 327

Re: Central Atom? [ENDORSED]

Hydrogen cannot be the central atom because it only can form one bond, therefore it cannot bond to multiple different atoms or satisfy the octet rule.
by Amelia Georgius 1K
Sun Dec 03, 2017 10:35 pm
Forum: Lewis Structures
Topic: Lewis Structure of IO2F2 (-2) Problem 4.23 [ENDORSED]
Replies: 3
Views: 1158

Re: Lewis Structure of IO2F2 (-2) Problem 4.23 [ENDORSED]

The closer the formal charge is to zero, the more stable it will be. So drawing the structure where more of the formal charges are closer to zero would be more stable and more preferred.
by Amelia Georgius 1K
Sun Nov 12, 2017 10:36 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Central Atom
Replies: 4
Views: 194

Re: Central Atom

For the most part, use the atom with the lowest electronegativity as the central atom unless the problem tells you otherwise
by Amelia Georgius 1K
Sun Nov 12, 2017 9:56 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Drawing lewis structures
Replies: 5
Views: 232

Re: Drawing lewis structures

Usually, if all the atoms have a formal charge of zero in the drawn structure, then that is the most stable form of the molecule.
by Amelia Georgius 1K
Sun Oct 22, 2017 11:05 pm
Forum: Photoelectric Effect
Topic: Post Module #17 [ENDORSED]
Replies: 3
Views: 240

Re: Post Module #17 [ENDORSED]

Increasing the intensity of the light, the amplitude of the wave, would not eject electrons, which showed that light had particle like properties because they were just increasing the number of photons rather than increasing their energy. If more photons were shone onto the metal with the same energ...
by Amelia Georgius 1K
Sun Oct 22, 2017 7:09 pm
Forum: Properties of Light
Topic: Light travels as a "wave"
Replies: 5
Views: 294

Re: Light travels as a "wave"

The way the way would travel, like diagonally or up and down etc, would be dependent upon the direction of the electric field and the magnetic field.
by Amelia Georgius 1K
Tue Oct 10, 2017 7:43 pm
Forum: Properties of Light
Topic: Problem 1.4
Replies: 3
Views: 167

Re: Problem 1.4

I'm confused with this problem as well because A. all waves travel at the speed of light, which is a constant, B. The wavelength of visible light increases as it changes from blue to green (but the frequency does decrease), and when you calculate the frequency of infrared radiation and radio waves, ...
by Amelia Georgius 1K
Tue Oct 10, 2017 7:27 pm
Forum: Properties of Light
Topic: Question 1.23
Replies: 2
Views: 277

Re: Question 1.23

An eV is an electron volt, which is another unit of energy. 1 eV = 1.60218x10^-19 J.
by Amelia Georgius 1K
Sun Oct 08, 2017 9:16 pm
Forum: Molarity, Solutions, Dilutions
Topic: Molarity unit [ENDORSED]
Replies: 11
Views: 633

Re: Molarity unit [ENDORSED]

It is usually easiest to convert all of your units to SI units at the beginning of a problem so that you are less likely to make an error in the calculation and answer, which in this case the SI unit is mol/L.
by Amelia Georgius 1K
Tue Oct 03, 2017 4:25 pm
Forum: SI Units, Unit Conversions
Topic: Molecules [ENDORSED]
Replies: 10
Views: 451

Re: Molecules [ENDORSED]

A mole is an amount of something, similar to how a dozen is 12 units of something, a mole is 6.022x10^23 units of something. A mole of molecules would be 6.022x10^23 molecules, where a single unit, in this example, would be a molecule.

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