Search found 63 matches

by Mark 1D
Sat Mar 16, 2019 7:05 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Assuming ideal gas
Replies: 3
Views: 50

Re: Assuming ideal gas

should usually assume, sometimes question also mentions it explicitly
by Mark 1D
Sat Mar 16, 2019 6:59 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium constant
Replies: 5
Views: 45

Re: Equilibrium constant

Catalyst has no effect on the equilibrium
by Mark 1D
Sat Mar 16, 2019 6:58 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Shifting K with changes in volume
Replies: 4
Views: 66

Re: Shifting K with changes in volume

Yes, less pressure (greater volume) will cause shift to side with more gas moles
by Mark 1D
Sat Mar 16, 2019 6:57 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Midterm, Question 2.B
Replies: 3
Views: 33

Re: Midterm, Question 2.B

1/K , which is the inverse I believe
by Mark 1D
Sat Mar 16, 2019 6:56 pm
Forum: Ideal Gases
Topic: Ideal gas constant R
Replies: 9
Views: 145

Re: Ideal gas constant R

depends on the units in the question
by Mark 1D
Tue Mar 12, 2019 12:17 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: stability of reactants and products
Replies: 3
Views: 38

Re: stability of reactants and products

Spontaneous reaction means products are more stable whilst spontaneous means the reactants will be more stable
by Mark 1D
Mon Mar 11, 2019 8:09 pm
Forum: Calculating Work of Expansion
Topic: Work
Replies: 8
Views: 102

Re: Work

whichever best suits and demands and variables of the question
by Mark 1D
Mon Mar 11, 2019 8:07 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Work done vs work on system
Replies: 18
Views: 243

Re: Work done vs work on system

work done by the system is negative, work done on the system is positive
by Mark 1D
Mon Mar 11, 2019 8:04 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Entropy based on shape of molecule
Replies: 3
Views: 60

Re: Entropy based on shape of molecule

entropy is greater for more complex molecules, so trans would be greater entrophy
by Mark 1D
Mon Mar 11, 2019 8:03 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Equilibrium Constant and Temperature
Replies: 2
Views: 51

Re: Equilibrium Constant and Temperature

i believe standard temperature is 25 C. /298 K, and the question may also state it
by Mark 1D
Mon Mar 11, 2019 8:02 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Formulas
Replies: 6
Views: 65

Re: Formulas

whichever is best suited to the needs and variables of the question
by Mark 1D
Mon Mar 11, 2019 8:01 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Calculating entropy
Replies: 4
Views: 47

Re: Calculating entropy

we isolate the two changes in entrophy and then add together
by Mark 1D
Mon Mar 11, 2019 7:59 pm
Forum: Phase Changes & Related Calculations
Topic: Steam vs Boiling Water
Replies: 8
Views: 126

Re: Steam vs Boiling Water

greater enthalpy and therefore more heat in steam
by Mark 1D
Mon Mar 11, 2019 7:57 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Finding heat(q)
Replies: 3
Views: 34

Re: Finding heat(q)

yes, depends on which is best suited to the question
by Mark 1D
Mon Mar 11, 2019 7:56 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Delta U
Replies: 5
Views: 50

Re: Delta U

Yes because if temperature is constant/not changing then the internal energy is therefore 0
by Mark 1D
Mon Mar 11, 2019 7:54 pm
Forum: Ideal Gases
Topic: ICE
Replies: 8
Views: 75

Re: ICE

x can be ignored, making x equal to 0
by Mark 1D
Mon Mar 11, 2019 7:53 pm
Forum: Ideal Gases
Topic: Cell Diagram/Ecell
Replies: 8
Views: 85

Re: Cell Diagram/Ecell

cathode gains electrons(reduction) whilst the anode loses electrons (oxidation)
by Mark 1D
Mon Mar 11, 2019 7:52 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Le Chatelier's Principle
Replies: 3
Views: 46

Re: Le Chatelier's Principle

the effects of temperature, pressure, adding or removal of reactants or products, or adding of inert gases on the equilibrium and if there will be shifts to left or right or no shift at all
by Mark 1D
Sun Mar 10, 2019 7:52 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Constant Vol.
Replies: 8
Views: 106

Re: Constant Vol.

Work is zero if no change in volume as there is no expansion or compression
by Mark 1D
Sun Mar 10, 2019 7:49 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Injecting noble gasses
Replies: 7
Views: 94

Re: Injecting noble gasses

Noble and inert gasses will cause no shift and no change in equilibrium constant
by Mark 1D
Sun Mar 10, 2019 7:48 pm
Forum: Ideal Gases
Topic: How do I know what is an Ideal Gas
Replies: 11
Views: 125

Re: How do I know what is an Ideal Gas

I think we are supposed to assume the gases in the questions are ideal gases. Sometimes the question will state it as well.
by Mark 1D
Sun Mar 10, 2019 7:46 pm
Forum: Ideal Gases
Topic: sre
Replies: 5
Views: 80

Re: sre

enthalpy of standard state for reactants and products (which are in their standard states)
by Mark 1D
Sun Mar 10, 2019 7:41 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: ignoring x
Replies: 16
Views: 212

Re: ignoring x

X is zero if follows 5% rule or if K is less than 10^-3. Therefore no need to use quadratic equation
by Mark 1D
Sun Mar 10, 2019 7:39 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Stability of reactants and products Midterm question
Replies: 3
Views: 40

Re: Stability of reactants and products Midterm question

The products will be more stable than the reactants when the equilibrium constant K is large
by Mark 1D
Sun Mar 10, 2019 7:38 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Units of Kp
Replies: 9
Views: 158

Re: Units of Kp

Bars or atms I believe
by Mark 1D
Sun Mar 10, 2019 7:37 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Approximation
Replies: 7
Views: 77

Re: Approximation

Approximate if it follows 5% rule or equilibrium constant is below x10^-3. But I sometimes use quadratic anyway to double check. :)
by Mark 1D
Sun Mar 10, 2019 7:35 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Midterm Ice Table
Replies: 6
Views: 106

Re: Midterm Ice Table

I believe we were not supposed to approximate and instead use the quadratic formula
by Mark 1D
Sun Mar 10, 2019 7:33 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Reverse Reaction
Replies: 8
Views: 92

Re: Reverse Reaction

Reverse reaction is 1/K, inverse relationship
by Mark 1D
Sun Mar 10, 2019 7:33 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Midterm
Replies: 5
Views: 63

Re: Midterm

The bigger the equilibrium constant, the more stable the products are
by Mark 1D
Sun Mar 10, 2019 7:32 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Negligible X
Replies: 3
Views: 37

Re: Negligible X

X is zero if 5% of initial concentration or if K less than 10^-3
by Mark 1D
Sun Mar 10, 2019 7:30 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium constant
Replies: 3
Views: 42

Re: Equilibrium constant

No units for K
by Mark 1D
Sun Mar 10, 2019 7:30 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equation I've never seen before?
Replies: 3
Views: 48

Re: Equation I've never seen before?

appears to be a form of PV=nrt
by Mark 1D
Sun Mar 10, 2019 7:29 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Final Exam
Replies: 23
Views: 188

Re: Final Exam

for sure will be on the final
by Mark 1D
Sat Dec 08, 2018 7:16 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: ions
Replies: 3
Views: 113

Re: ions

Cations lose electrons, giving a positive charge
by Mark 1D
Sat Dec 08, 2018 7:11 pm
Forum: Lewis Acids & Bases
Topic: H-
Replies: 3
Views: 49

Re: H-

Bronsted base because H- is a proton acceptor
by Mark 1D
Sat Dec 08, 2018 7:07 pm
Forum: Lewis Structures
Topic: Lewis Acids & Bases
Replies: 3
Views: 91

Re: Lewis Acids & Bases

Lewis acids are defined as accepting a pair of electrons whilst the Lewis bases are donors of electrons. So it would be based on whether the molecule accepts or gives electron pairs
by Mark 1D
Sat Dec 08, 2018 7:03 pm
Forum: Electronegativity
Topic: Exceptions
Replies: 3
Views: 87

Re: Exceptions

I do not think there are exceptions to the electronegativity trend which goes up and to the right on the periodic table
by Mark 1D
Sat Dec 08, 2018 7:02 pm
Forum: Hybridization
Topic: Expanded Octet Hybridizations
Replies: 2
Views: 70

Re: Expanded Octet Hybridizations

because d orbitals allow those elements to have expanded octets so hybridization can show the d along with the s and p orbitals due to the large amount of valence electrons
by Mark 1D
Fri Dec 07, 2018 8:33 pm
Forum: Lewis Acids & Bases
Topic: Lewis v Bronsted
Replies: 2
Views: 46

Re: Lewis v Bronsted

Lewis describes lewis acid as an acceptor of a lone pair of electrons whilst Bronstead describes an acid as a donor of a proton
by Mark 1D
Fri Dec 07, 2018 8:31 pm
Forum: Lewis Structures
Topic: Elements that break the octet rule
Replies: 6
Views: 120

Re: Elements that break the octet rule

The elements in the d block can violate the octet rule because of the presence of the d orbital into which more electrons can reside
by Mark 1D
Fri Dec 07, 2018 8:30 pm
Forum: Hybridization
Topic: pi vs sigma
Replies: 12
Views: 186

Re: pi vs sigma

Sigma bonds overlap more than pi bonds, allowing for more strength whilst also allowing for rotation
by Mark 1D
Fri Dec 07, 2018 8:27 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizing Power: Size vs. Charge
Replies: 3
Views: 112

Re: Polarizing Power: Size vs. Charge

Smaller atomic radius cations have more polarizing power. A higher charge also gives more polarizing power
by Mark 1D
Fri Dec 07, 2018 8:25 pm
Forum: Octet Exceptions
Topic: Exceptions
Replies: 7
Views: 183

Re: Exceptions

elements in the d block are exceptions as they are able to fill their d orbital with more electrons, allowing for an expanded octet
by Mark 1D
Fri Dec 07, 2018 8:23 pm
Forum: Electronegativity
Topic: Ionic Character
Replies: 5
Views: 112

Re: Ionic Character

I believe oxygen is more electronegative as it is higher than chlorine on the periodic table
by Mark 1D
Fri Dec 07, 2018 8:21 pm
Forum: Sigma & Pi Bonds
Topic: Number of sigma and pi bonds
Replies: 5
Views: 138

Re: Number of sigma and pi bonds

a single bond corresponds to a sigma bond, whilst a double bond is 1 sigma and 1 pi and a triple bond is 1 sigma and 2 pis
by Mark 1D
Fri Dec 07, 2018 8:18 pm
Forum: Properties of Electrons
Topic: Orbitals
Replies: 5
Views: 189

Re: Orbitals

p shell has 3 orbitals I believe
by Mark 1D
Fri Dec 07, 2018 8:15 pm
Forum: Properties of Light
Topic: Speed of light
Replies: 13
Views: 206

Re: Speed of light

3X10^8 should be fine I think
by Mark 1D
Sun Nov 25, 2018 8:13 pm
Forum: Hybridization
Topic: 2F.1 7th Edition
Replies: 1
Views: 30

2F.1 7th Edition

Can someone explain the solution for 2F.1 in the 7th Edition? "State the relative orientation of each of the following hybrid orbitals: (a)sp^3; (b) sp; (c)sp^3d^2; (d) sp^2.
by Mark 1D
Sun Nov 25, 2018 8:06 pm
Forum: Hybridization
Topic: Octet Expansion
Replies: 6
Views: 81

Re: Octet Expansion

electrons fill up the s and p orbital. once those orbitals are filled, d orbital is needed for an atom to have more than 8 valence electrons
by Mark 1D
Sun Nov 25, 2018 8:01 pm
Forum: Bond Lengths & Energies
Topic: Why Are Double Bonds Shorter
Replies: 3
Views: 53

Why Are Double Bonds Shorter

Howdy partners. What is the reasoning for why double bonds are shorter (and therefore stronger) than single bonds? Thanks
by Mark 1D
Sun Nov 25, 2018 7:53 pm
Forum: Octet Exceptions
Topic: Understanding Expanded Octets
Replies: 1
Views: 58

Understanding Expanded Octets

Howdy. Can one of ya'll explain how having a greater number of orbitals, such as a d orbital, allow an element to have an expanded octet? Thanks.
by Mark 1D
Sun Oct 28, 2018 8:15 pm
Forum: Ionic & Covalent Bonds
Topic: 2A.21 7th Edition Question
Replies: 2
Views: 27

2A.21 7th Edition Question

Howdy ya'll. Can someone explain why the ground state electron configuration for Ag^+ is [Kr]4d^10 in question 2A.21? Thanks
by Mark 1D
Sun Oct 28, 2018 8:06 pm
Forum: Ionic & Covalent Bonds
Topic: 2A.6 7th Edition
Replies: 1
Views: 31

2A.6 7th Edition

Howdy! 2A.6 asks for the ground-state electron configuration of the ion P^3-. Can someone explain how I would go about solving this?
by Mark 1D
Sun Oct 28, 2018 8:00 pm
Forum: Ionic & Covalent Bonds
Topic: Question regarding ionic bonds
Replies: 9
Views: 106

Question regarding ionic bonds

Howdy partners. Are ionic bonds always between non-metals and metals?
by Mark 1D
Sun Oct 21, 2018 8:02 pm
Forum: Properties of Electrons
Topic: Concept Behind Orbitals
Replies: 6
Views: 102

Concept Behind Orbitals

Howdy there. I was wondering about the conceptual explanation behind why higher orbitals have more energy. Is it because of distance from the positively charged nucleus?
by Mark 1D
Sun Oct 21, 2018 8:00 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: HW Question Regarding 1B.27
Replies: 6
Views: 132

HW Question Regarding 1B.27

Howdy! 1B.27 says "A bowling ball of masss 8.00 kg is rolled down a bowling alley lane at 5.00 +/ 5.0 m/s. What is the minimum uncertainty in its position?" Can one of ya'll explain to me how I use the uncertainty equation to obtain the minimum uncertainty?
by Mark 1D
Sun Oct 21, 2018 7:55 pm
Forum: DeBroglie Equation
Topic: 1B. 25 7th Edition
Replies: 2
Views: 45

1B. 25 7th Edition

Howdy ya'll. 1B.25 states "What is the minimum uncertainty in the speed of an electron confined within a lead atom of diameter 350 pm? Can somebody explain how to obtain the solution please. Thanks
by Mark 1D
Sun Oct 14, 2018 8:25 pm
Forum: Properties of Light
Topic: Photons
Replies: 4
Views: 98

Re: Photons

A single photon requires the sufficient energy needed to remove a single electron. :)
by Mark 1D
Sun Oct 14, 2018 8:23 pm
Forum: Properties of Light
Topic: Measurable Wavelengths
Replies: 3
Views: 40

Measurable Wavelengths

Does anybody know how long a wavelength must be to be "measurable"?
by Mark 1D
Sun Oct 14, 2018 8:19 pm
Forum: Properties of Light
Topic: 1A.3 7th Edition Question
Replies: 4
Views: 69

1A.3 7th Edition Question

1A.3 Which of the following happens when the frequency of electromagnetic radiation decreases? Explain your reasoning. (c) The extent of the change in the electrical field at a given point decreases. Can someone explain what happens to the "extent of the change in the electrical field at a give...
by Mark 1D
Sun Oct 07, 2018 6:09 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: E15 7th Edition
Replies: 1
Views: 63

E15 7th Edition

The molar mass of the metal hydroxide M(OH)2 is 74.10 gmol. What is the molar mass of the sulfide of this metal? I understand how to obtain molar mass but how do I identify the sulfide of M(OH)2? Thanks
by Mark 1D
Sun Oct 07, 2018 6:06 pm
Forum: SI Units, Unit Conversions
Topic: Question regarding showing units within work
Replies: 2
Views: 64

Question regarding showing units within work

When working on the answer to a question, does anybody know if we have to show units in our work? I understand our final answer must have units.
by Mark 1D
Sun Oct 07, 2018 6:03 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Atomic Weight vs Molecular Weight
Replies: 2
Views: 40

Re: Atomic Weight vs Molecular Weight

I believe atomic weight is the measured weight of the atom whilst the molecular weight is the measured weight of the molecule (so add weights of the atoms within the molecule). ;)

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