Search found 32 matches

by Jessica Dharmawan 1G
Fri Dec 07, 2018 10:53 pm
Forum: Biological Examples
Topic: What should we know for the final?
Replies: 6
Views: 152

What should we know for the final?

Are there any specific biological examples that we need to know for the final? In terms of structure, function, etc.
by Jessica Dharmawan 1G
Sun Dec 02, 2018 4:55 pm
Forum: Administrative Questions and Class Announcements
Topic: Final [ENDORSED]
Replies: 5
Views: 152

Re: Final [ENDORSED]

I feel like there might be a practice final because Lyndon, who did the Garlic Bread midterm questions last time, has a session on Friday. He might tell us in class during one of the lectures this week. Also, I assume that the TAs and UAs will also go over practice final questions during their own s...
by Jessica Dharmawan 1G
Wed Nov 28, 2018 3:35 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic/Covalent bond cut offs
Replies: 1
Views: 67

Ionic/Covalent bond cut offs

What are the electronegativity cut offs that can be used to determine if a bond is ionic/covalent?
by Jessica Dharmawan 1G
Sun Nov 25, 2018 7:03 pm
Forum: Properties of Light
Topic: Speed of light
Replies: 13
Views: 204

Speed of light

When doing calculations, should we use 2.99792 × 108 m.s-1 or 3.00 × 108 m.s-1 for the speed of light?
I used the 3.00 × 108 m.s-1 on the midterm and got an answer that was two hundredths off and got it marked wrong, so what should be the accurate number to use?
by Jessica Dharmawan 1G
Sun Nov 25, 2018 6:58 pm
Forum: Limiting Reactant Calculations
Topic: Finding limiting reagent
Replies: 1
Views: 88

Finding limiting reagent

What is the easiest/quickest way to determine what the limiting reagent in a chemical reaction is?
by Jessica Dharmawan 1G
Sun Nov 25, 2018 6:56 pm
Forum: Hybridization
Topic: Hybridization scheme
Replies: 3
Views: 42

Hybridization scheme

What's the easiest way to determine hybridization schemes for certain molecules?
by Jessica Dharmawan 1G
Fri Nov 16, 2018 11:48 am
Forum: Sigma & Pi Bonds
Topic: Significance of sigma and pi bonds
Replies: 2
Views: 59

Significance of sigma and pi bonds

What's the significance of sigma and pi bonds? How are they useful to know when looking at molecular interactions?
by Jessica Dharmawan 1G
Fri Nov 16, 2018 11:27 am
Forum: Hybridization
Topic: General definition/context
Replies: 2
Views: 74

General definition/context

What is hybridization in general, in terms of its definition as well as how it is used in the context of this lesson?
by Jessica Dharmawan 1G
Fri Nov 16, 2018 9:38 am
Forum: Formal Charge and Oxidation Numbers
Topic: Shortcut
Replies: 4
Views: 134

Re: Shortcut

The shortcut is basically to first count how many electrons are surrounding a single atom. For example, when looking at the formal charge for Cl in PCl 5 , you would count that there are 6 lone electrons and then one electron right next to the Cl that is being shared with the P (in other words, only...
by Jessica Dharmawan 1G
Sun Nov 11, 2018 8:38 pm
Forum: Bond Lengths & Energies
Topic: Determine bond length
Replies: 3
Views: 89

Determine bond length

Is there a way to determine bond length of a Lewis structure with single/double/triple bonds? Or does that information have to be given to us in the problem?
by Jessica Dharmawan 1G
Sun Nov 04, 2018 9:05 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: When to multiply by 2
Replies: 5
Views: 170

When to multiply by 2

When do we multiply the uncertainty in p or x or v by 2? I'm getting confused when doing calculations.
by Jessica Dharmawan 1G
Sun Nov 04, 2018 8:46 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Post-Module Q#18
Replies: 3
Views: 131

Re: Post-Module Q#18

The radius of the atom represents 1/2 of the uncertainty of the position of the electron, the diameter equaling the entire uncertainty. the size of the atom represents the uncertainty in position. You can use this uncertainty, as well as the mass of an electron and the constant h/4pi to calculate d...
by Jessica Dharmawan 1G
Sun Nov 04, 2018 6:21 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Post-Module Q#18
Replies: 3
Views: 131

Post-Module Q#18

The question states: The hydrogen atom has a radius of approximately 0.05 nm. Assume that we know the position of an electron to an accuracy of 1 % of the hydrogen radius, calculate the uncertainty in the speed of the electron using the Heisenberg uncertainty principle. Comment on your value obtaine...
by Jessica Dharmawan 1G
Sun Nov 04, 2018 6:09 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Post-Module Q#17
Replies: 1
Views: 74

Post-Module Q#17

The question states: Calculate the uncertainty (indeterminacy) in position of an electron if its uncertainty in speed is one hundredth the speed of light.

Does this mean the uncertainty is 3x10^6? if so, does delta v = 2(3x10^6)?
by Jessica Dharmawan 1G
Sat Nov 03, 2018 8:29 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Post-Module Q#42
Replies: 1
Views: 75

Post-Module Q#42

The question asks: An excited hydrogen atom emits light with a frequency of 1.14 x 10^14 Hz to reach the energy level n = 4. In what principle quantum level did the electron begin?

What is the easiest way to solve this?
by Jessica Dharmawan 1G
Sat Nov 03, 2018 11:52 am
Forum: Properties of Light
Topic: Photoelectric Effect - waves vs. photons
Replies: 3
Views: 122

Photoelectric Effect - waves vs. photons

In the photoelectric effect, do we look at the light as waves or photons? I keep getting confused with questions asking for example: if long wavelength light is not ejecting e- from a surface, will increasing intensity of light result in e- being ejected?? I think increasing the intensity of light w...
by Jessica Dharmawan 1G
Fri Nov 02, 2018 9:05 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Sig figs???
Replies: 1
Views: 81

Sig figs???

When there's a problem asking for the change in energy from n=3 to n=1 of a hydrogen atom, how many sig figs should our answer have, since there's only one sig fig from the given data?
by Jessica Dharmawan 1G
Mon Oct 29, 2018 9:26 am
Forum: Ionic & Covalent Bonds
Topic: Roman numerals next to element
Replies: 8
Views: 174

Re: Roman numerals next to element

Roman numerals are used to name the different ions of the transition metals. An example would be: Cu3+ named as Cu(III).
by Jessica Dharmawan 1G
Mon Oct 29, 2018 9:23 am
Forum: Trends in The Periodic Table
Topic: Periodic table
Replies: 4
Views: 119

Re: Periodic table

I know that ionization energy is the energy needed to remove an electron from an atom. The further away the electron is from the nucleus, the easier it is to remove the electron. Ionization energies decrease down a group and increase across a period.
by Jessica Dharmawan 1G
Mon Oct 29, 2018 9:17 am
Forum: Quantum Numbers and The H-Atom
Topic: Finding number of elements that have given quantum numbers
Replies: 1
Views: 76

Finding number of elements that have given quantum numbers

What is the easiest way to find the number of elements that have given quantum numbers?
Example: given n = 5 and l = 1, how many elements can have these quantum numbers?
by Jessica Dharmawan 1G
Mon Oct 29, 2018 9:12 am
Forum: Properties of Light
Topic: Photoelectric Effect
Replies: 7
Views: 217

Re: Photoelectric Effect

As the light source is increased in intensity, then the number of electrons ejected increases. Light intensity is proportional to the number of electrons ejected.
by Jessica Dharmawan 1G
Mon Oct 29, 2018 9:09 am
Forum: Significant Figures
Topic: Sig Figs in the Middle of a Problem
Replies: 9
Views: 324

Re: Sig Figs in the Middle of a Problem

It is better to round off at the end of the problem, instead of in the middle of a calculation, to ensure accuracy. Use as many digits as possible in the middle of a calculation and just carry those numbers over until you're at the end of the problem.
by Jessica Dharmawan 1G
Wed Oct 24, 2018 9:02 pm
Forum: Properties of Light
Topic: SI Units
Replies: 6
Views: 151

Re: SI Units

Should we also know conversions like M (mega)? It was on the homework so I'm just wondering
by Jessica Dharmawan 1G
Sun Oct 21, 2018 10:47 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Test Question
Replies: 8
Views: 104

Re: Test Question

It's good to know them for context and conceptual understanding, but we don't have to know how to draw them.
by Jessica Dharmawan 1G
Sun Oct 21, 2018 10:44 pm
Forum: Properties of Light
Topic: Test 2 Equations
Replies: 14
Views: 240

Test 2 Equations

What are the equations we should memorize for Test 2?
by Jessica Dharmawan 1G
Sun Oct 21, 2018 10:42 pm
Forum: Quantum Numbers and The H-Atom
Topic: Lyman, Balmer, Pascal
Replies: 10
Views: 204

Re: Lyman, Balmer, Pascal

Do we have to memorize these for the test this week?
by Jessica Dharmawan 1G
Fri Oct 12, 2018 8:23 pm
Forum: SI Units, Unit Conversions
Topic: formula units [ENDORSED]
Replies: 68
Views: 21375

Re: formula units [ENDORSED]

I looked at formula units as the number of atoms/molecules, depending on what is given. I used Avogadro's number to find the formula units asked for in the problem.
by Jessica Dharmawan 1G
Fri Oct 12, 2018 8:22 pm
Forum: Limiting Reactant Calculations
Topic: Test 1
Replies: 8
Views: 328

Re: Test 1

The test was fairly straightforward, and most of the problems were similar to the homework problems. It was also pretty short, and most of us finished early, giving us time to even check back on all of the problems again.
by Jessica Dharmawan 1G
Mon Oct 08, 2018 10:45 pm
Forum: Limiting Reactant Calculations
Topic: How to find the limiting reactant easily and quickly
Replies: 5
Views: 233

How to find the limiting reactant easily and quickly

I'm having trouble finding easy ways to determine the limiting reactant. Any advice??? There is also a problem in one of the post-assessment modules that asks questions about the chemical equation 2A + 1B --> 3C, such as what reactant is in excess and what is the maximum amount of product that can b...
by Jessica Dharmawan 1G
Fri Oct 05, 2018 9:24 am
Forum: Limiting Reactant Calculations
Topic: When to use H vs H2
Replies: 7
Views: 129

Re: When to use H vs H2

I believe you do multiply by 2 when using H2. Because there are two atoms of hydrogen, you would multiply the molar mass of 1 H atom by 2 to get the total molar mass of H2.
by Jessica Dharmawan 1G
Fri Oct 05, 2018 9:10 am
Forum: Balancing Chemical Reactions
Topic: Post-Module Assessment typo?? - Balancing Chemical Reactions
Replies: 3
Views: 129

Post-Module Assessment typo?? - Balancing Chemical Reactions

On question #17, it asks us to balance the equation .
I believe the correct answer is C) , but the survey says it is wrong, maybe it's a typo?
by Jessica Dharmawan 1G
Fri Oct 05, 2018 9:01 am
Forum: Balancing Chemical Reactions
Topic: How To....
Replies: 16
Views: 516

Re: How To....

I believe Dr. Lavelle said we should include the state of matter when balancing an equation. We will probably be able to recognize the states of matter as we go along and do problems, so I think we will pick it up eventually. If not, then the state of matter will be stated in the question. To balanc...

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