Search found 33 matches

by Alma Carrera 3C
Sat Dec 08, 2018 6:09 pm
Forum: Amphoteric Compounds
Topic: As2O3
Replies: 1
Views: 28

As2O3

Why would As2O3 be considered amphoteric? Can someone show me a chemical equation in which it acts as both an acid and a base?
by Alma Carrera 3C
Sat Dec 08, 2018 5:54 pm
Forum: Lewis Acids & Bases
Topic: 6th edition 12.17
Replies: 5
Views: 64

Re: 6th edition 12.17

Is there a way to tell based on the lewis structures or do we just have to remember this?
by Alma Carrera 3C
Sat Dec 08, 2018 5:33 pm
Forum: Lewis Acids & Bases
Topic: 6th edition 12.17
Replies: 5
Views: 64

6th edition 12.17

BaO is basic according to the solutions manual. Can someone explain why?
by Alma Carrera 3C
Sun Dec 02, 2018 5:15 pm
Forum: Hybridization
Topic: Hybridization
Replies: 5
Views: 56

Re: Hybridization

Yes because there are 4 regions of e- density around the central atom.
by Alma Carrera 3C
Sun Dec 02, 2018 4:14 pm
Forum: Bronsted Acids & Bases
Topic: 6th ed: Fundamentals J.1
Replies: 4
Views: 60

Re: 6th ed: Fundamentals J.1

But how would you know which ones lose a proton and which ones gain a proton?
by Alma Carrera 3C
Sun Dec 02, 2018 3:18 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Acid vs base [ENDORSED]
Replies: 15
Views: 171

Re: Acid vs base [ENDORSED]

How do you know if a compound is an acid or base simply by looking at the compound name?
by Alma Carrera 3C
Sun Nov 25, 2018 10:09 pm
Forum: Hybridization
Topic: Question 4.43 (Sixth Edition)
Replies: 2
Views: 41

Re: Question 4.43 (Sixth Edition)

The s-character is the percentage of the s-orbital in the hybrid. If it is a larger percentage that means their are less bonds and so the bond angles will be larger.
by Alma Carrera 3C
Sat Nov 24, 2018 1:59 pm
Forum: Hybridization
Topic: hybridization problems
Replies: 4
Views: 49

Re: hybridization problems

It may help to draw out the Lewis Structure so you can easily see how many electron density regions there are including lone pairs.
by Alma Carrera 3C
Sat Nov 24, 2018 1:58 pm
Forum: Hybridization
Topic: 4.43 6th Edition
Replies: 1
Views: 28

4.43 6th Edition

This question asks how the bond angle between two hybrid orbitals would change as the s-character of the hybrids is increased. What exactly does it mean by increasing the s-character?
by Alma Carrera 3C
Sun Nov 18, 2018 7:43 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Determining Shape
Replies: 5
Views: 68

Re: Determining Shape

Yes, it depends on the lone pairs since they cause more repulsion. For example, a tetrahedral and a trigonal pyramid both have 4 regions of e- density but since the trigonal pyramid has a lone pair, the high repulsion causes the bond angles to be slightly smaller than those in a tetrahedral.
by Alma Carrera 3C
Sun Nov 18, 2018 7:39 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Repulsion Strength
Replies: 2
Views: 45

Re: Repulsion Strength

Lone pairs of electrons cause much more repulsion, therefore when there is a lone pair present, it will "push away" the other atoms and decrease their bond angles.
by Alma Carrera 3C
Sun Nov 18, 2018 4:20 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: bond angle and bond strength
Replies: 4
Views: 43

Re: bond angle and bond strength

Since all bonds are treated equivalently, they type of bond (whether its a single, double, triple) wouldn't affect its shape.
by Alma Carrera 3C
Sun Nov 11, 2018 6:27 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: molecular shapes
Replies: 13
Views: 135

Re: molecular shapes

I don't think Dr. Lavelle has mentioned the trigonal pyramidal shape, but it is the answer to question 4.7 in the 6th edition. It also says that the bond angles are 109.5 degrees (which is the same angle as a tetrahedral shape) so are these two shapes the same?
by Alma Carrera 3C
Sun Nov 11, 2018 6:06 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pairs
Replies: 7
Views: 85

Re: Lone Pairs

So would H2O have a trigonal planar shape or a tetrahedral shape?
by Alma Carrera 3C
Sun Nov 11, 2018 5:15 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: bond angles and lone pairs
Replies: 4
Views: 51

bond angles and lone pairs

How do you determine if there "may" be or "must" be lone pairs based off of the bond angles?
by Alma Carrera 3C
Sun Nov 04, 2018 8:39 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge on Central Atom
Replies: 9
Views: 101

Re: Formal Charge on Central Atom

The structure will be more stable if the central atom has a formal charge of 0, which is why we always to give the central atom a formal charge of 0.
by Alma Carrera 3C
Sun Nov 04, 2018 11:35 am
Forum: Ionic & Covalent Bonds
Topic: Homework Problem 3.19
Replies: 2
Views: 35

Re: Homework Problem 3.19

Using the valence electrons, fill out the outermost shell by following Hund's Rule, which says to fill in 1 electron in each orbital first and then start pairing them once each orbital 1 electron. Then you can see how many electrons remain unpaired.
by Alma Carrera 3C
Fri Nov 02, 2018 8:03 pm
Forum: Ionic & Covalent Bonds
Topic: 3.23 6th Edition
Replies: 3
Views: 31

3.23 6th Edition

This question asks for the maximum positive and negative oxidation numbers that Chlorine can have. The answers are +7 and -1, respectively. Can someone explain to me how these numbers are derived?
by Alma Carrera 3C
Sun Oct 28, 2018 7:28 pm
Forum: Trends in The Periodic Table
Topic: Electron affinity trend
Replies: 2
Views: 47

Re: Electron affinity trend

In lecture, Dr. Lavelle said that there is generally high electron affinity for elements in the top right of the periodic table. This is why Helium has the highest electron affinity.
by Alma Carrera 3C
Fri Oct 26, 2018 11:36 pm
Forum: Trends in The Periodic Table
Topic: Atomic Radius
Replies: 8
Views: 94

Atomic Radius

I understand that the atomic radii decreases along the periods and increases down the groups, but do we have to know the actual radius? For example in problem 2.57 from the 6th edition, they include the actual radius of the elements, but I don't know where they got those values from.
by Alma Carrera 3C
Fri Oct 26, 2018 9:52 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 2.43 6th edition
Replies: 1
Views: 41

2.43 6th edition

For Tungsten, the electron configuration is written as [Xe] 4f14 5d4 6s2. I thought 6s is always written before 5d unless 5d is full, which in this case it's not. Can someone please explain this to me?
by Alma Carrera 3C
Fri Oct 26, 2018 6:17 pm
Forum: Quantum Numbers and The H-Atom
Topic: Test #2
Replies: 2
Views: 59

Re: Test #2

I think it would depend on what the question is specifically asking for. If it asks for all the possible quantum numbers then you would include all the possible values of m.
by Alma Carrera 3C
Fri Oct 19, 2018 2:40 pm
Forum: Properties of Light
Topic: Inverse Relationships?
Replies: 4
Views: 54

Re: Inverse Relationships?

if you refer back to the equation: speed of light(c)=wavelength(lambda) x frequency(v) you'll see that the product of wavelength times frequency must equal the speed of light which is a set value. Therefore when the wavelength decreases the frequency must increase and vice versa. The units for wavel...
by Alma Carrera 3C
Thu Oct 18, 2018 8:39 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: 6th Edition, 1.43
Replies: 1
Views: 54

6th Edition, 1.43

What is the minimum uncertainty in the speed of an electron confined to within a lead atom of diameter 350. pm? Model the atom as a one dimensional box with a length equal to the diameter of the actual atom. Can someone explain to me what steps they took when solving for this problem please? I'm ver...
by Alma Carrera 3C
Thu Oct 18, 2018 2:36 pm
Forum: DeBroglie Equation
Topic: H.W. Problem 1.55
Replies: 3
Views: 544

Re: H.W. Problem 1.55

I think they are multiplying by 100cm/m to convert the speed of light from m/s to cm/s. That is how I interpreted the answer.
by Alma Carrera 3C
Sat Oct 13, 2018 7:25 pm
Forum: Properties of Light
Topic: Wave vs. Photon
Replies: 2
Views: 38

Wave vs. Photon

Can someone please explain what the difference is between a wave of light and a photon of light? Thanks :)
by Alma Carrera 3C
Fri Oct 12, 2018 2:31 pm
Forum: Properties of Light
Topic: Question 1.3 6th edition
Replies: 2
Views: 38

Re: Question 1.3 6th edition

The extent of change is basically the slope of the wave. We know that low frequency is associated with a long wavelength, so if the frequency decreases then the wavelength must increase. If the wavelength increases, that means that the waves have broadened and the slope has decreased. Therefore, the...
by Alma Carrera 3C
Fri Oct 12, 2018 2:18 pm
Forum: Properties of Light
Topic: Kinetic energy equation
Replies: 4
Views: 37

Re: Kinetic energy equation

Yeah, Professor Lavelle said we would be given a sheet with all the constants so its not necessary to memorize them, but after using them over and over again it'll eventually stick to you.
by Alma Carrera 3C
Thu Oct 04, 2018 9:49 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: F 5 Percent Composition
Replies: 4
Views: 33

Re: F 5 Percent Composition

You have to find the mass percentage of each element. In order to do this, first find the molar mass of each element and add them up to get the total molar mass of the compound, C7H15NO3. Then divide the molar masses of each element by the total molar mass of the compound and multiply by 100 to get ...
by Alma Carrera 3C
Wed Oct 03, 2018 12:36 am
Forum: Molarity, Solutions, Dilutions
Topic: Module question
Replies: 4
Views: 89

Re: Module question

Yeah, so your mistake was multiplying the number of moles by .075 L. The 75 ml of water were used to dissolve the KCl, but the total volume was actually 125 ml. So all you need to do is follow the formula C=n/V, so you would divide the number of moles of KCl by the total volume in Liters, .125 L.
by Alma Carrera 3C
Tue Oct 02, 2018 11:41 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: 6th Edition Question E29b
Replies: 1
Views: 48

Re: 6th Edition Question E29b

It would be twice the amount in part (a) because in 1 mol of copper(II) chloride tetrahydrate there are 2 Cl atoms. Therefore, you multiply the number of moles from (a) times 2.
by Alma Carrera 3C
Fri Apr 06, 2018 11:42 am
Forum: Molarity, Solutions, Dilutions
Topic: G.5 [ENDORSED]
Replies: 3
Views: 141

Re: G.5 [ENDORSED]

They are just multiplying by the ratio because for every mole of Na2CO2 there are 2 moles of Na.
by Alma Carrera 3C
Fri Apr 06, 2018 11:26 am
Forum: Molarity, Solutions, Dilutions
Topic: G. 9 [ENDORSED]
Replies: 2
Views: 104

Re: G. 9 [ENDORSED]

Actually for this question you multiply the molarity of AgNO3 which they want (.179 M) x the volume in liters ( .500 L) x the molar mass of AgNO3 (169.88g/mol) to get the mass in grams of AgNO3 needed.

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