CHEMISTRY COMMUNITY

Yixiao Hu 3C

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

Yixiao Hu 3C

Yes. It depends on the reaction you have.

Yixiao Hu 3C

because Bi is a metalloid.

Yixiao Hu 3C

A substance which can act as either an acid or a base is described as being amphoteric.

Yixiao Hu 3C

as long as you have a metalloid in the formula, the substance is a amphoteric compound.

Yixiao Hu 3C

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

Yixiao Hu 3C

BaO is basic; any group1 metal's oxide are basic

Yixiao Hu 3C

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...

Yixiao Hu 3C

higher electronegativity difference means stronger acids (imagine H2S and HF)

Yixiao Hu 3C

acids donate H+ and accepts e-; while bases donate e- and accepts H+

Yixiao Hu 3C

the number of p orbitals

Yixiao Hu 3C

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.

Yixiao Hu 3C

I think they are the same thing, just in different ways of telling

Yixiao Hu 3C

Yes, shape for an AX2E and AX2E2 molecule are bent.

Yixiao Hu 3C

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.

Yixiao Hu 3C

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

Yixiao Hu 3C

atoms before the period 3 must have a octet rule. Meanwhile, except the central atom, atoms aside should also obey the octet rule

Yixiao Hu 3C

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

Yixiao Hu 3C

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

Yixiao Hu 3C

because it is on the period 3, so it order to have the lowest energy structure, the pcl5 can break the octet rule.

Yixiao Hu 3C

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.

Yixiao Hu 3C

that one is absolutely fine.

Yixiao Hu 3C

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

Yixiao Hu 3C

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

Yixiao Hu 3C

you mean the central atom ? choose atom with lowest ionization energy as central atom

Yixiao Hu 3C

choose the atom with the lowest ionization energy as the central atom

Yixiao Hu 3C

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

Yixiao Hu 3C

line means shared electrons, while the dots means lone pairs. These two are used in different situations and should be treated differently

Yixiao Hu 3C

when a atom has 8 valence electrons it is an octet

Yixiao Hu 3C

I think it does matter. You should put electron on each side first and then make the pairs.

Yixiao Hu 3C

Because you two positive particles will repel to each other.

Yixiao Hu 3C

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

Yixiao Hu 3C

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

Yixiao Hu 3C

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.

Yixiao Hu 3C

1.hv=c
2.lamthum=h/p=h/mv
3.E-work function=1/2mv2

Yixiao Hu 3C

molarity=m(kcal)/M(kcal)/V(KCL)

Yixiao Hu 3C

I think you should use l instead of ml, for the l is the standard units

Yixiao Hu 3C

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.

Yixiao Hu 3C

It depends on the question. But usually ,when we say molarity, it should be L for 1 molarity= 1mol/l

Yixiao Hu 3C

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.

Yixiao Hu 3C

I think you can use if whenever you have all the numbers. mv=mv is available all the time without any contidions:)

Yixiao Hu 3C

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)...

Yixiao Hu 3C

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+

Yixiao Hu 3C

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.

Yixiao Hu 3C

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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