Search found 45 matches

by Yixiao Hu 3C
Fri Dec 07, 2018 12:15 am
Forum: Amphoteric Compounds
Topic: Acidic, Basic, and Amphoteric Oxides
Replies: 2
Views: 38

Re: Acidic, Basic, and Amphoteric Oxides

It would be basic if you have metal element in the formula; it would be acid if you have nonmetal element in the formula; it would be amphoteric if you have metalloid in the formula
by Yixiao Hu 3C
Fri Dec 07, 2018 12:14 am
Forum: Amphoteric Compounds
Topic: Amphoteric clarification
Replies: 5
Views: 61

Re: Amphoteric clarification

Yes. It depends on the reaction you have.
by Yixiao Hu 3C
Fri Dec 07, 2018 12:13 am
Forum: Amphoteric Compounds
Topic: 7th ed. 6A17
Replies: 3
Views: 54

Re: 7th ed. 6A17

because Bi is a metalloid.
by Yixiao Hu 3C
Fri Dec 07, 2018 12:13 am
Forum: Amphoteric Compounds
Topic: Definition
Replies: 6
Views: 85

Re: Definition

A substance which can act as either an acid or a base is described as being amphoteric.
by Yixiao Hu 3C
Fri Dec 07, 2018 12:12 am
Forum: Amphoteric Compounds
Topic: Determining Amphoteric Compounds
Replies: 3
Views: 32

Re: Determining Amphoteric Compounds

as long as you have a metalloid in the formula, the substance is a amphoteric compound.
by Yixiao Hu 3C
Fri Dec 07, 2018 12:11 am
Forum: Amphoteric Compounds
Topic: What makes As2O3 Amphoteric?
Replies: 2
Views: 53

Re: What makes As2O3 Amphoteric?

A substance which can act as either an acid or a base is described as being amphoteric. An amphiprotic substance is one which can both donate hydrogen ions (protons) and also accept them.
As2O3 is amphoteric because As is a metalloid
by Yixiao Hu 3C
Fri Dec 07, 2018 12:09 am
Forum: Amphoteric Compounds
Topic: BaO
Replies: 5
Views: 785

Re: BaO

BaO is basic; any group1 metal's oxide are basic
by Yixiao Hu 3C
Sat Dec 01, 2018 1:25 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: H+ Acidic and OH- Basic
Replies: 4
Views: 155

Re: H+ Acidic and OH- Basic

I think that's only two ways of demonstrating. Acids and Bases: Lewis vs. Bronsted. There are two complementary definitions of acids and bases that are important: the Bronsted (or Bronsted-Lowry) definition: an acid is a proton (H+ ion) donor, and a base is a proton acceptor; the Lewis definition: a...
by Yixiao Hu 3C
Sat Dec 01, 2018 1:23 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Strength of an acid
Replies: 14
Views: 438

Re: Strength of an acid

higher electronegativity difference means stronger acids (imagine H2S and HF)
by Yixiao Hu 3C
Sat Dec 01, 2018 1:21 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Acid vs base [ENDORSED]
Replies: 15
Views: 170

Re: Acid vs base [ENDORSED]

acids donate H+ and accepts e-; while bases donate e- and accepts H+
by Yixiao Hu 3C
Sun Nov 25, 2018 4:12 pm
Forum: Hybridization
Topic: sp orbitals
Replies: 3
Views: 54

Re: sp orbitals

the number of p orbitals
by Yixiao Hu 3C
Sun Nov 25, 2018 4:11 pm
Forum: Hybridization
Topic: double bonds
Replies: 14
Views: 144

Re: double bonds

a double bond has one pi bond and one sigma bond. In a triple bond, there is one sigma bond and two pi bonds now due an additional side-to-side overlap.
by Yixiao Hu 3C
Sun Nov 25, 2018 4:07 pm
Forum: Hybridization
Topic: Hybridization and Hybrid Orbitals
Replies: 4
Views: 45

Re: Hybridization and Hybrid Orbitals

I think they are the same thing, just in different ways of telling
by Yixiao Hu 3C
Fri Nov 23, 2018 10:06 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent - Lone Pairs
Replies: 8
Views: 132

Re: Bent - Lone Pairs

Yes, shape for an AX2E and AX2E2 molecule are bent.
by Yixiao Hu 3C
Fri Nov 23, 2018 10:05 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pairs on the Central Atom
Replies: 5
Views: 69

Re: Lone Pairs on the Central Atom

because the substance wants its structure to be energy minimized; but the lone pairs and the electrons bonds will have repulsive forced which require more energy. in order to reduce energy, the bond electrons will go away from the lone pairs, affecting the shape.
by Yixiao Hu 3C
Fri Nov 23, 2018 10:02 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Difference Between Position and Shape
Replies: 2
Views: 37

Re: Difference Between Position and Shape

shape is determined two parts of electrons: bonds and lonely pairs.we only have to memorize the shape of the substance based on the vespl model
by Yixiao Hu 3C
Thu Nov 15, 2018 12:35 am
Forum: Lewis Structures
Topic: Octet rule question
Replies: 6
Views: 114

Re: Octet rule question

atoms before the period 3 must have a octet rule. Meanwhile, except the central atom, atoms aside should also obey the octet rule
by Yixiao Hu 3C
Thu Nov 15, 2018 12:34 am
Forum: Lewis Structures
Topic: VSEPR Model
Replies: 6
Views: 113

Re: VSEPR Model

from the previous learning, we actually did not really how the molecules look like or its shape; the resonance and the double or more bond we learn actually does not have any effect for the shape. so from the vsepr model, we should learn the practical model
by Yixiao Hu 3C
Thu Nov 15, 2018 12:31 am
Forum: Lewis Structures
Topic: Formal Charge
Replies: 14
Views: 192

Re: Formal Charge

I think it is better to have zero formal charge on the central atom; though the electronegativity is also very important, the formal charge of the central atom is more important
by Yixiao Hu 3C
Mon Nov 05, 2018 9:51 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Why does PCl5 break the Octet Rule?
Replies: 8
Views: 164

Re: Why does PCl5 break the Octet Rule?

because it is on the period 3, so it order to have the lowest energy structure, the pcl5 can break the octet rule.
by Yixiao Hu 3C
Mon Nov 05, 2018 9:49 pm
Forum: Administrative Questions and Class Announcements
Topic: Do we need to memorize formulas and constants?
Replies: 2
Views: 438

Re: Do we need to memorize formulas and constants?

no. I think all the equations and constant are covered in the test paper. The only thing we need to know is to make sure that we know how to use those equations.
by Yixiao Hu 3C
Mon Nov 05, 2018 9:48 pm
Forum: Administrative Questions and Class Announcements
Topic: Type of calculator
Replies: 8
Views: 140

Re: Type of calculator

that one is absolutely fine.
by Yixiao Hu 3C
Mon Nov 05, 2018 9:47 pm
Forum: Administrative Questions and Class Announcements
Topic: Memorizing equations [ENDORSED]
Replies: 5
Views: 170

Re: Memorizing equations [ENDORSED]

I think all the equations will be posted on the test material. The only thing we need to do is to make sure we know how to use them
by Yixiao Hu 3C
Mon Nov 05, 2018 9:46 pm
Forum: Administrative Questions and Class Announcements
Topic: Question from textbook
Replies: 2
Views: 47

Re: Question from textbook

Use 2.111g Na2CO3 and the 250.0mL to get the molarity. 0.08mol/L.
Take the 2.15mmol Na+ ion and convert into moles. There are two Na+ ion per Na2CO3 molecule. Using the molarity, we can convert that into how many liters of the solution we need.
you can find the answers for part c by the same way
by Yixiao Hu 3C
Mon Oct 29, 2018 3:12 pm
Forum: Lewis Structures
Topic: lewis structure
Replies: 10
Views: 207

Re: lewis structure

you mean the central atom ? choose atom with lowest ionization energy as central atom
by Yixiao Hu 3C
Mon Oct 29, 2018 3:11 pm
Forum: Lewis Structures
Topic: central atom
Replies: 7
Views: 80

Re: central atom

choose the atom with the lowest ionization energy as the central atom
by Yixiao Hu 3C
Mon Oct 29, 2018 3:09 pm
Forum: Lewis Structures
Topic: 2 lone pairs
Replies: 5
Views: 131

Re: 2 lone pairs

it does not matter whether you put it on the top or at the bottom. The only thing you only need to pay attention to is to put these two dots on different sides
by Yixiao Hu 3C
Mon Oct 29, 2018 3:07 pm
Forum: Lewis Structures
Topic: Lines that Represent Bonds
Replies: 7
Views: 65

Re: Lines that Represent Bonds

line means shared electrons, while the dots means lone pairs. These two are used in different situations and should be treated differently
by Yixiao Hu 3C
Mon Oct 29, 2018 3:06 pm
Forum: Lewis Structures
Topic: octets
Replies: 13
Views: 120

Re: octets

when a atom has 8 valence electrons it is an octet
by Yixiao Hu 3C
Mon Oct 29, 2018 2:05 pm
Forum: Lewis Structures
Topic: Dots in Lewis Stucture
Replies: 14
Views: 188

Re: Dots in Lewis Stucture

I think it does matter. You should put electron on each side first and then make the pairs.
by Yixiao Hu 3C
Mon Oct 29, 2018 2:04 pm
Forum: Lewis Structures
Topic: Lewis Structure for Compounds
Replies: 6
Views: 90

Re: Lewis Structure for Compounds

Because you two positive particles will repel to each other.
by Yixiao Hu 3C
Mon Oct 29, 2018 2:02 pm
Forum: Lewis Structures
Topic: Delocalized Electrons
Replies: 5
Views: 69

Re: Delocalized Electrons

delocalized electrons are electrons in a molecule, ion or solid metal that are not associated with a single atom or a covalent bond. The term is general and can have slightly different meanings in different fields. It's just a general term and I don't think it will be tested
by Yixiao Hu 3C
Sat Oct 20, 2018 8:56 pm
Forum: Properties of Light
Topic: De Broglie's equation
Replies: 6
Views: 89

Re: De Broglie's equation

you can only use v=h/p for things with matter, for p=mv. if you wanna use that equation for massless photons, you willl be unable to put any numbers for m
by Yixiao Hu 3C
Sat Oct 20, 2018 8:48 pm
Forum: Properties of Light
Topic: Calculating the wavelength of light
Replies: 7
Views: 80

Re: Calculating the wavelength of light

it is both correct to use c=3x10*8or 2.998x10*8; the only difference is that the latter is more precise. I think in the exams you can use c=3x10*8 directly.
by Yixiao Hu 3C
Sat Oct 20, 2018 8:46 pm
Forum: Properties of Light
Topic: Equations
Replies: 7
Views: 95

Re: Equations

1.hv=c
2.lamthum=h/p=h/mv
3.E-work function=1/2mv2
by Yixiao Hu 3C
Sat Oct 13, 2018 3:13 pm
Forum: Molarity, Solutions, Dilutions
Topic: Molarity and Dilution
Replies: 8
Views: 1464

Re: Molarity and Dilution

molarity=m(kcal)/M(kcal)/V(KCL)
by Yixiao Hu 3C
Sat Oct 13, 2018 3:12 pm
Forum: Molarity, Solutions, Dilutions
Topic: Changing Units
Replies: 10
Views: 208

Re: Changing Units

I think you should use l instead of ml, for the l is the standard units
by Yixiao Hu 3C
Sat Oct 13, 2018 3:10 pm
Forum: Molarity, Solutions, Dilutions
Topic: Molarity
Replies: 4
Views: 121

Re: Molarity

you shouldn't use m1v1=m2v1 this time. the equation you should use is that the mole of kmno4 is the same. so you should calculate the moles of kmno4 in the 20ml solution first.
by Yixiao Hu 3C
Sat Oct 13, 2018 3:07 pm
Forum: Molarity, Solutions, Dilutions
Topic: Units?
Replies: 8
Views: 149

Re: Units?

It depends on the question. But usually ,when we say molarity, it should be L for 1 molarity= 1mol/l
by Yixiao Hu 3C
Sun Oct 07, 2018 11:22 pm
Forum: Molarity, Solutions, Dilutions
Topic: Calculation error help!
Replies: 2
Views: 192

Re: Calculation error help!

you should use the formula n=m/M for the moles of kcl; and then you should use the formula molarity=n/v . the first 75ml here is just useless. you only need the final volume.
by Yixiao Hu 3C
Sun Oct 07, 2018 11:18 pm
Forum: Molarity, Solutions, Dilutions
Topic: Molarity formula
Replies: 6
Views: 171

Re: Molarity formula

I think you can use if whenever you have all the numbers. mv=mv is available all the time without any contidions:)
by Yixiao Hu 3C
Sun Oct 07, 2018 11:12 pm
Forum: Molarity, Solutions, Dilutions
Topic: Mixtures and Solutions
Replies: 2
Views: 61

Re: Mixtures and Solutions

c is the concentration of solution, while n equals the mole of the matter and v equals the volume the solution.It's better to understand in this way, if you wanna know how matter is concentrated in the solution in the units of mole, you should divide the total amount of matter( in the unit of mole0)...
by Yixiao Hu 3C
Sun Oct 07, 2018 11:07 pm
Forum: Molarity, Solutions, Dilutions
Topic: Why amount of CH3CO2- doubled for each Ca(CH3CO2)2
Replies: 4
Views: 517

Re: Why amount of CH3CO2- doubled for each Ca(CH3CO2)2

Cause if you wanna have Ca(CH3CO2)2, you have to have one Ca+ and two (CH3CO2) at the same time. so when you are going to calculate the concentration of ca(ch3co2)2, the concentration of ch3co2- must be two times of that of ca+
by Yixiao Hu 3C
Sun Oct 07, 2018 11:02 pm
Forum: Molarity, Solutions, Dilutions
Topic: Why doesn't a solute add to the volume of a solution? [ENDORSED]
Replies: 6
Views: 803

Re: Why doesn't a solute add to the volume of a solution? [ENDORSED]

Compared to the volume of the solution, or to the solvent, the volume of your solute is so tiny; at the same time, the solute will dissolve in your solvent. So the solute will not account to the volume of a solution.
by Yixiao Hu 3C
Sun Oct 07, 2018 10:58 pm
Forum: Significant Figures
Topic: Number of significant figures when using Ka and Kb
Replies: 2
Views: 338

Re: Number of significant figures when using Ka and Kb

I think you should depend your SF on other numbers, instead of Ka and Kb. Ka and Kb will change due to several factors.

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