CHEMISTRY COMMUNITY

vivianndo_1L

This helps so much!!! Thank you :)

One quick question though, how do you know to tell the difference between a weak and strong acid/base based on its formula alone?

vivianndo_1L

Will we be given the oxidation numbers for the final?

vivianndo_1L

Select an acid and a base for a neutralization reaction that results in the formation of: a) potassium bromide b) zinc nitrite c) calcium cyanide d) potassium phosphate Write the balanced equation for each reaction. How do I begin this problem? How do I determine whether an element (for instance, z...

vivianndo_1L

Where did you see the 2H2O? I only saw H2O in the answer

vivianndo_1L

Can someone please explain to me how to start the process of writing the overall, complete ionic, and net ionic equations for acid-base reactions? I'm still really confused about how to do it all. Here's an example problem that I kinda know how to do but maybe it would help with explaining the steps...

vivianndo_1L

J.5a HF(aq) + NaOH(aq) -> NaF(aq) + H2O(l) -Why is the complete ionic equation for this problem HF + Na+ + OH- -> Na+ + F- + H2O and not H+ + F- + Na+ + OH- -> Na+ + F- + H2O ? J.5b (CH3)3N(aq) + HNO3(aq) -> (CH3)N3HNO3(aq) -I don't understand why (CH3)3N(aq) + HNO3(aq) just combines to become (CH3...

vivianndo_1L

When it asks us to draw the structure of molecules so that we can determine its molecular shape, do we draw it as a ball-and-stick diagram or do we use a Lewis structure? I know the answer in the back of the book is in the form of a Lewis diagram but I just wanted to clarify.

vivianndo_1L

Heteronuclear atoms with an electronegativity difference: -of >2 are considered mainly ionic bonds -of <1.5 are considered mainly covalent bonds What about the range inbetween? Is it difficult to tell when the number is between 1.5 and 2 (acts as a gray area and determining bonds depends on a host o...

vivianndo_1L

Can someone please explain to me why the Lewis structure of ICl4^-1 looks like this?

How is it determined that there are 2 lone pairs surrounding iodine?

vivianndo_1L

Okay, cool, thanks so much!

vivianndo_1L

If the two resonance structures have the same formal charge, would they be considered equal in rank?

vivianndo_1L

How would I start the process of drawing a Lewis structure with multiple compounds?

For instance, 3.41b asks us to draw the structure for CH3OH. How would I begin? Same goes for 3.41c: H2C(NH2)COOH

vivianndo_1L

You can also remember "FONCL" from class as it describes the trend in electronegativity--as you go from F to L, electronegativity decreases.

vivianndo_1L

Oh okay I see, thanks!

vivianndo_1L

Honestly I took a bunch of random steps and hoped it worked out. I started with the molar masses to figure out the moles being used during the combustion. Because we know that ~0.3 grams of nicotine were burned and what the products were, I calculated how many moles of nicotine was in the 0.3 sample...

vivianndo_1L

Use the following SI units:

-meter (m) for length
-kilogram (kg) for mass
-second (s) for time
-Kelvin (K) for temperature

There are only 7 SI units I believe and every other unit is derived from these. I only listed the ones I found relevant for this test.

vivianndo_1L

Here's a really good Crash Course video that helps conceptualize diffraction and its significance in Quantum Theory:

https://youtu.be/IRBfpBPELmE

It'll help visualize the constructive and destructive waves as well.

vivianndo_1L

The y-ray photons emitted by the nuclear decay of a technetium-99 atom used in pharmaceuticals have an energy of 140.511 keV. Calculate the wavelength of these y-rays.

I managed to convert the keV to Joules but now I don't know what to do. Can someone please help?

vivianndo_1L

Which elements are predicted to have the following ground-state electron configurations:

(d) [Rn] 7s^2 6d^2

Why is the answer Th (thorium)? I know that the d orbital comes before f, but isn't thorium an actinoid (therefore belonging in the f-block)? I'm really confused, please help!

vivianndo_1L

I understand why a = 6 electrons and why b/d = 2 electrons, but why is c = 8 electrons?

vivianndo_1L

So are shells and energy levels interchangeable?

vivianndo_1L

Could anyone help me figure out the reason WHY the values of ml go from "-l" to "l" though? I feel like I'm still conceptually confused.

vivianndo_1L

Does the stoichiometric coefficient of a substance indicate its number of moles?

For instance, is 2H2O equivalent to 2 moles of H2O?

vivianndo_1L

I'm still a little confused about what Coulomb's Potential Energy is. Could someone please explain its significance and whether or not we need to thoroughly understand it for the midterm?

vivianndo_1L

To help memorize the electromagnetic spectrum I generally start from the middle of the spectrum. Visible light ranges from ~400nm to ~700nm. Because waves at 400nm emit VIOLET light, waves a bit below that number are ultraVIOLET. Then, because waves at 700nm emit RED light, waves a bit above that nu...

vivianndo_1L

Regarding intensity, its properties vary according to which model you're looking at. In the wave model, the intensity of the radiation is proportional to the square amplitude of the wave. In the particle model, the intensity of the radiation is proportional to the number of photons present at each i...

vivianndo_1L

When referring to light in the aspect of the wave-particle duality, the intensity of the light and its properties vary according to which model you're looking at. In the wave model, the intensity of the radiation is proportional to the square amplitude of the wave. In the particle model, the intensi...

vivianndo_1L

The "surprise" was that Planck proposed energy was transferred in discrete packets (photons) which discarded classical physics. In classical physics, there is no restriction on how small an amount of energy may be transferred from one object to another. However, quantum mechanics focuses o...

vivianndo_1L

How does constructive/destructive interference relate to the wave-particle duality then? I'm still a little confused

vivianndo_1L

Could someone please explain the relationship between the ultraviolet catastrophe and black bodies then?

CHEMISTRY COMMUNITY

Search found 30 matches

Re: Acid-Base Reactions and Ionic Equations

Oxidation Numbers (Final) [ENDORSED]

J.7 Select Acids and Bases

Re: J.5

Acid-Base Reactions and Ionic Equations

J.5a&b

4.3 Structure and Shape [ENDORSED]

Re: ionic and covalent character

3.61

Re: Multiple Compounds (3.41)

Re: ranking

Multiple Compounds (3.41)

Re: electronegativity chart

Re: 1.23 Homework

Re: Question 3 on midterm [ENDORSED]

Re: units

Re: Diffraction Patterns

1.23 Homework

2.45

Re: HW 2.29 [ENDORSED]

Re: Shells?

Re: Clarification on magnetic quantum number

Stoichiometric Coefficient vs Moles

Coulomb Potential Energy [ENDORSED]

Re: Electromagnetic Spectrum [ENDORSED]

Re: Difference between wave model and particle model? [ENDORSED]

Re: Amplitude and Intensity

Re: photoelectric effect

Re: Wave and Particle Properties of Electrons and Photons

Re: Black Body? [ENDORSED]