CHEMISTRY COMMUNITY

huntercrespo1C

Wants to prepare 200.0 mL of a 0.025 M HCl solution but uses a 250.0 mL flask
I understand part a but where does the equation pH = -log * (200mL * .025M)/250.0M come from for part b

huntercrespo1C

Calculate the initial molarity of Ba(OH)2 and the molarities of Ba2+, OH-, and H3O+ in an aqueous solution that contains 0.43h of Ba(OH)2 in 0.1L of solution. For this one I understand how to get the molares of Ba2+ and OH- by finding the number of mols of Ba(OH)2 then doing the math but I don’t und...

huntercrespo1C

State whether the following oxides are acids or bases or amphoteric.
For these, what is the best way to determine what they are by drawing the Lewis structure and then seeing if they want to gain or lose electrons?

huntercrespo1C

Estimate the bond angles... when you are finding bond angles of an element with mutliple bonds how do you just find one of them?

huntercrespo1C

Noting that the bond angle of an sp3 hybridized atom is 109.5 and that of an sp2 hybridized atom is 120, do you expect the bond angle between two hybrid orbitals to increase or descremase as the s character of the hybrids is increased? In this question what is meant by the “s character” because isn’...

huntercrespo1C

When there are more than 2 elements in a molecule how do you determine whether they are polar or non polar?

huntercrespo1C

This one asked for the most stable lewis structure of carbon monoxide and I drew it as C with two lone pair electrons double bonded to an O with four lone pair of electrons but the right answer is C with two lone pair electrons triple bonded to O with one lone pair electron. I am confused on this be...

huntercrespo1C

I am pretty sure in molecules like this one of the lone pairs are going backwards (into the board) and one of the lone pairs are going forward (out of the board) and it is just hard to visualize when we are writing this on paper.

huntercrespo1C

Which do you predict to have the stronger CX bond, where x is a halogen CF4, CCl4, CBr4
How do you judge the strength of the bond using length when they all are connected by only 4 single bonds?

huntercrespo1C

What are all the elements with expanded octects that we are expected to know?

huntercrespo1C

How is the Lewis structure for this one correct if neither of them have full octects and the formal charge is a 4?

huntercrespo1C

For this one the answers are
A) NO2- isn’t a radical
B) CH3 is a radical
Which I understand but for
C) BF4- I get 32 electrons but it says that it is a radical
D) BRO I get 11 electrons and it says it’s NOT a radical so am I doing something wrong or why is this?

huntercrespo1C

For b (the second one) when you get O formal charge of -1 and S formal charge of 1 do those cancel out and equal a formal charge of 0? If so, why aren’t the two structures equal in energy?

huntercrespo1C

It doesn't matter as long as they are going in parallel with each other to fill all the orbitals, but conventionally they start with a (+1/2) or up arrow spin.

huntercrespo1C

For these, how do we know which letter should be in the middle? I know it is lowest ionization energy but what if two elements are in two different rows and groups? How can you tell?

huntercrespo1C

On the basis of the expected charges on the monatomic ions, give a chemical formula of each of the following ions?
Can someone please run through how to do these?

huntercrespo1C

In the review session he explained that although ionization energies increase across a period when comparing C, N, O, F the order is C O N then F
I know he said that O is more inclined to lose an electron than N but why?

huntercrespo1C

What is a diagonal relationship? I looked it up and it said similarity in chemical properties between an element in the periodic table ande one group lying one period lower and one group to the right.
I don’t remember him talking about this in class... do we need to know it for the midterm?

huntercrespo1C

Which element of the following has a higher electron affinity?
So electron affinity means: amount of energy released when an electron is added to a neutral atom or molecule in the gaseous state to form a (-) ion.
Is this the same as ionization energy? What is the trend for this?

huntercrespo1C

How many electrons can occupy the...
Is there an easier way to memorize/ understand how many orbitals each level has or do I just have to memorize the chart?

huntercrespo1C

What are the principal and orbital angular momentum quantum numbers for each of the following orbitals?
for d) 5f, why does l = 3?

huntercrespo1C

Describe the orientation of the lobes in the px, py, and pz orbitals with respect to the cartesian axis. The answers to this made sense because the lobes are orientated along the corresponding letters (px orbital will have its lobes orientated along the x axis) But what do these lobes refer to and w...

huntercrespo1C

Can someone please explain to be the difference between constructive and destructive waves and what exactly it means?

huntercrespo1C

For the wavelengths spectrum do we need to know all the exact lengths for microwave, infrared, visible (red, orange, yellow, green, blue, violet), x- ray, y-ray or just the general idea?

huntercrespo1C

Lines in the Balmer series of the hydrogen spectrum observed at 656.3, 486.1, 434.0 and 410.2 nm. What is the wave length of the next line in the series?
I understand that n1 is 2 because its the Balmer series but how do you get n2 is 7, shouldn’t it be 6?

huntercrespo1C

Rydbery formula:
V=R(1/n1^2 + 1/n2^2)
C=vλ
So you can just substitute Rydbery formula for V since thats what it equals.
C=R(1/n1^2 + 1/n2^2)λ

Then just plug in your numbers

huntercrespo1C

What is common to the lines within a series that makes grouping them together logical?

huntercrespo1C

Calculate the wavelength of radiation (using the Rydberg formula) generated by the transition from n=4 to n=2.

In the answer n1= 2 and n2= 4 but I don’t understand why it isn’t the other way around because its going from 4-2.

huntercrespo1C

A solution is prepared by dissolving 55.1 g of KCl in approximately 75 mL of water and then adding water to a final volume of 125 mL. What is the molarity of KCl in this solution?

huntercrespo1C

PCl3 + 3H2O -> 3HCl + H3PO3. What mass is produced by the reaction of 23.6 g of PCl?

huntercrespo1C

750 g of CHH9Cl13 is mixed with 1.0 kg of AgNO3 in a flask of water. AgCl precipitates out - what is the mass of AgCl.

CHEMISTRY COMMUNITY

Search found 31 matches

12.27

12.15

12.17

4.109

4.43

4.27

Test 3 Q2

Re: How to know what position lone pair electrons will be at?

3.87

Expanded octects

3.59

3.55

3.53 b

Re: Electron configuration

3.33

3.25/ 3.27

Unicorn practice test 6d.

2.71

2.67

2.25

2.21

2.13

Wave properties of electrons

Wavelengths

1.57 [ENDORSED]

Re: Homework 1.13 [ENDORSED]

1.11

Question 1.13

Video 4 - post assessment [ENDORSED]

Video 3 Post- assessment [ENDORSED]

Video 3 Post- assessment