Search found 19 matches

by Courtney Cheney 3E
Fri Dec 08, 2017 3:14 pm
Forum: Molarity, Solutions, Dilutions
Topic: Solutions
Replies: 5
Views: 404

Re: Solutions

Part 3 reply: So for part 3 you are using the stock solution of 2.00M NaOH from part two to make 250mL (250mL X 1000mL/ 1L = 0.250L) of a 0.650M NaOH. For this question you need to use the (Mi)(Vi) = (Mf)(Vf) Given: Mf = 0.650 M Vf = 0.250 L Mi = 2.00 M Vi = ??? So you plug the values in..... (2.00 ...
by Courtney Cheney 3E
Fri Dec 08, 2017 2:54 pm
Forum: Molarity, Solutions, Dilutions
Topic: Solutions
Replies: 5
Views: 404

Re: Solutions

An easy way to know that you have to multiply the number of moles by the molecular weight is by looking at what the value is being expressed in. So for example: O.02 is expressed in moles, and molecular weight is expressed in grams / mole so to get moles to grams you have to multiply the number of m...
by Courtney Cheney 3E
Fri Dec 08, 2017 2:45 pm
Forum: Molarity, Solutions, Dilutions
Topic: Solutions
Replies: 5
Views: 404

Re: Solutions

0.02 is the amount of moles of sodium carbonate that need to be added to the flask, however you then need to multiply the number of moles of sodium carbonate by the molecular weight of sodium carbonate so you know how many grams you need to add to the flask to make your stock solution.
by Courtney Cheney 3E
Fri Dec 08, 2017 2:39 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kc
Replies: 2
Views: 227

Re: Kc

I believe Kc is the same for gases as it is for other solutions. It is just the equilibrium consent for the reaction when given concentrations. Though I'm pretty sure Kp is more commonly used as the equilibrium consent for gases but since the concentration is directly related to partial pressures vi...
by Courtney Cheney 3E
Wed Dec 06, 2017 4:19 pm
Forum: Conjugate Acids & Bases
Topic: Conjugate Acid and Base
Replies: 5
Views: 364

Re: Conjugate Acid and Base

We learned today in my class that congregate bases and conjugate acids can actually change the pH of a solution if they are conjugates of weak bases/acids... Does this mean that all salts formed from weak acids/ bases will have the ability to change the pH of a neutral solution?
by Courtney Cheney 3E
Wed Dec 06, 2017 4:08 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Strength of an Acid
Replies: 5
Views: 491

Re: Strength of an Acid

Since HF, HCl, HBr, and HI are in the same group, we have to relate them through bond strength and since the H-F bond is stronger than the H-I bond, HI is a stronger acid. This is all due to the fact that the weaker the bond between the A and H, the more easily the H dissociates from the A.
by Courtney Cheney 3E
Wed Dec 06, 2017 4:07 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Strength of an Acid
Replies: 5
Views: 491

Re: Strength of an Acid

I got really confused to! But the book goes on to explain that "Acid strengths of binary acids across a period correlate with electron affinities; acid strengths down a group correlate with bond strength."
by Courtney Cheney 3E
Wed Dec 06, 2017 3:49 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: How to assume X is too small
Replies: 3
Views: 351

Re: How to assume X is too small

I don't think so. My TA went over this today in discussion and said that when doing concentration calculations you're almost always going to assume X is too small and then check with the 5% rule. However, he did mention that if the concentration given is rather large (in the example in class it was ...
by Courtney Cheney 3E
Mon Nov 13, 2017 5:48 pm
Forum: Ionic & Covalent Bonds
Topic: Midterm
Replies: 6
Views: 570

Re: Midterm

I believe that the difference in electronegativity guideline(the <1.5 or >2) only works to determine if the molecule is an ionic bond or covalent bond. And then you have to figure out the shape and dipole moments to determine polarity
by Courtney Cheney 3E
Mon Nov 13, 2017 5:33 pm
Forum: Ionic & Covalent Bonds
Topic: Midterm
Replies: 6
Views: 570

Re: Midterm

I'm confused because Silicon has 4 ve- while both Oxygen's have 6 ve- which add up to a total of 16 ve-. So when you draw the Lewis Structure, you're going to get Silicon double bonded to each Oxygen atom and 2 sets of lone pairs on each Oxygen. (The two double bonds makeup 8e- while the 2 set of lo...
by Courtney Cheney 3E
Mon Nov 13, 2017 5:11 pm
Forum: Octet Exceptions
Topic: Radicals
Replies: 2
Views: 254

Re: Radicals

Additionally question, would it be okay if the element that does have the radical to have less than an octet?
by Courtney Cheney 3E
Mon Nov 13, 2017 5:09 pm
Forum: Octet Exceptions
Topic: Radicals
Replies: 2
Views: 254

Radicals

When referring to radicals, in general the unpaired e- can't defy the ocete rule right? For example if a carbon atom in a radical molecule already has 4 single bonds then the unpaired e- has to belong to another atom in the element? or no?
by Courtney Cheney 3E
Tue Oct 31, 2017 12:22 pm
Forum: Trends in The Periodic Table
Topic: 2.67
Replies: 5
Views: 401

Re: 2.67

I understand a) Fluorine, c) Chlorine, and d) Lithium; however the book states that the answer for b) is Carbon???

Can anyone explain why carbon has a higher electron affinity over nitrogen? Even though it is to the left of nitrogen?
by Courtney Cheney 3E
Tue Oct 31, 2017 12:18 pm
Forum: Trends in The Periodic Table
Topic: 2.67
Replies: 5
Views: 401

2.67

Which element of each of the following pairs has the HIGHER electron affinity:

a) Oxygen or Fluorine
b) Nitrogen or Carbon
c) Chlorine or Bromine
d) Lithium or Sodium
by Courtney Cheney 3E
Sat Oct 28, 2017 12:47 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Homework 2.37 [ENDORSED]
Replies: 7
Views: 3082

Re: Homework 2.37 [ENDORSED]

Can someone explain what the effective nuclear charge is please??? :)
by Courtney Cheney 3E
Thu Oct 26, 2017 4:06 pm
Forum: Trends in The Periodic Table
Topic: Electron Affinity vs Electronegativity
Replies: 2
Views: 1148

Electron Affinity vs Electronegativity

Can someone explain the difference between electron affinity and electronegativity, or the relationship between the two. I'm having a hard time distinguishing them.
by Courtney Cheney 3E
Sat Oct 14, 2017 5:54 pm
Forum: Einstein Equation
Topic: What is the eV unit? [ENDORSED]
Replies: 6
Views: 3156

Re: What is the eV unit? [ENDORSED]

Is it necessary to memorize the conversion J?
by Courtney Cheney 3E
Tue Oct 10, 2017 1:17 pm
Forum: Properties of Light
Topic: Amplitude
Replies: 6
Views: 531

Re: Amplitude

If your told one wave of light has higher energy than another do you assume that the amplitude is higher, the frequency is higher, both, or can it not be determined?
by Courtney Cheney 3E
Sat Oct 07, 2017 10:57 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8017
Views: 1401977

Chemistry Jokes

Atom 1: "I lost an electron!"
Atom 2: "Yeah, you really have to keep an ion them."

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