CHEMISTRY COMMUNITY

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Is a triprotic acid an acid with 3 hydrogens?

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Is there a difference between rate or consumption of a reactant and the rate a product is formed?

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Is emf E or Enot?

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Van Hoff's can find a K value knowing two different temperature or it can find a temperature knowing two different K values.

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It changes based on whether it is integers or in ln form.

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Make sure to write units when calculating. That makes it a lot easier to tell which units it's supposed to be. Also if you're given the order you can know what units k is suppose to be in.

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If you remember temperature is the only thing that can change K.

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You are often times given information for E or Ecell.

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you can find K. Then since you know either k2 or k1 you can just plug one into the other. K= K2/ K1

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You have to make everything is balanced. P4 is the reactant for both equations. After you've split the equations balance the O's then balance the H's and lastly balance the charges. In a basic solution, you add H2O and OH to balance the reactions. Then you add elections to whichever side has the lea...

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Yes. Br2 is the reactant in both half reactions.

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Also he might ask questions about the cathode and anode and the second method gives you a better understanding of what is going on.

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I had trouble with this one too. With 6OH and 6H2O the equation is still not balanced that's why you need 12OH and 12 H2O.

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What do you mean by "what kind you're doing"? I would think that it is always in kelvins.

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Yes, T is constant. In general if there it is a delta change or a ratio of T there is a change in temperature, but if it is just T temperature is constant.

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Delta G is spontaneity. From what I understand is if delta G is spontaneous it is also endothermic and if delta G is negative it is not spontaneous and it is exothermic.

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Also what exactly is residual entropy?

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How do you know when to assume it is a monatomic gas?

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I'm very confused as to why the textbook inter changes between delta H and q. I thought they weren't the same thing, but for many solutions the textbook will substitute delta H for q. Can someone please explain to me why this is possible.

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Because there are 4 TNT and you want to find it for just 1 mole of TNT.

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In the homework the textbook often assumes something is an ideal gas or the pressure is constant. How do we know when we can make assumptions like those?

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Okay I feel really dumb for asking this but is J.C-1.mol-1 equal to J/C.mol or J/C/mol?

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You need to always have the same units, but delta t is a change in final and initial and 1 C change is equivalent to 1 K change thats why you were able to calculate delta T in C because it is the same as in K.

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I don't think there is a part of the equation that accounts for attractive and repulsive forces on each other.

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Also you might have to switch some of the equations and make the products the reactants. If you do so make sure the multiply the enthalpy by -1 of the specific reaction.

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Heat capacity just depends on the final and initial values that is why it is a state property.

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The ice tables can be used with moles, concentration, pressure but you need to make sure you know what you're using so that you can convert correctly at the end.

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yes, there is just an initial concentration for the salt as well as the weak acid. But the steps are the same.

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It depends on the molecules. For instance 25 degrees C is the equilibrium temperature for water.

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you can still do the 5% rule he sort of did an example like this in lecture on Wednesday I believe.

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You can use it for both you just need to pay attention to what you are using when coming up with a final answer.

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yes since there is more reactant more product will be formed.

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K value doesn't determine if its spontaneous or not.

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how do you know when your suppose to subtract just x or subtract something like 2x?

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It depends on your TA. If you want to get you test back before we go to break email your TA.

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Cl is a large atom than F so that means the the bond length of HCl is longer than the bond length of HF so HCl has a weak bond. Since the bond is weaker HCl is more likely to donate the H+ making it a stronger acid.

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If a molecule or element is outside of the brackets like Cl3 then it would just be chloride not tricholoro.

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A negative pH can be calculated, I'm just not sure why. But it is possible.

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When he says use the VSPER Model his is saying to refer to it when answering the question. So you should take in consideration the formula, shape (lone pairs), and bond angles.

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I don't think so.

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You do need to know that single bonds are the longest, then it's doubles bonds and triple bands are the shortest out of the three.

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I've just memorized the shapes it is the quickest way to name molecules which is really important for the test since you don't want to run out of time.

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the molecular shape helps more because it shows the actual arrangement of the atoms where as the geometry just says how many bonds or regions of bonds around the central atom. The geometry doesn't include lone pairs.

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Usually the central atom doesn't have a high formal charge. It depends what the charge is of the full compound. If the compound is neutral then the central atom should have a formal charge of 0 or a formal charge that cancels out the formal charge of the other atoms.

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We haven't gone over this in lecture as far as I know. Dr. Lavelle will most likely answer you question in the following lectures.

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If the central atom has three bonds and no lone pairs then it will be trigonal planar it doesn't matter if the elements are different.

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He doesn't post grades on CCLE just on my UCLA, but he hasn't updated grades as far as I know.

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Because CO2 has double bonds and H2O doesn't.

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How do you know which end of a molecule is delta positive or delta negative?

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My PLF said that for example if you got the value 1.09 you can't assume 1 but anything lower than 1.09 you can assume one. So in general if it is less than .09 away from a whole number you can still round to that whole number.

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You should always check the formula charge when you're drawing a lewis structure no matter way. This way you can make sure that the lewis structure you drew is the best one.

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I'm pretty sure we won't need to know how many resonance structures we need to draw, the problems will tell us how many resonance we need to draw.

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We only need to know the things Dr. Lavelle covered up until wednesday's lecture.

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How do I do 5a because I know that Copper can have exceptions. Give the ground-state electron configuration expected for
each of the following ions: Cu^+

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Want to hear a joke about sodium, bromine, and oxygen?
NaBrO

almaochoa2D · Re: Friday 10/26/18 lecture ionic and covalent bonds

ionic and covalent bonds

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Does anyone know if we're suppose to know about electron configuration for the test? He said we would only need to know the stuff he lecture about up until friday's lecture, but he didn't really go over electron configuration and that is in outline 2. I don't know if I should study it for the test.

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Also the DeBroglie Equations is for objects with mass.

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The symbol doesn't need to be there because you are just finding the missing value. The symbol is just there for the purpose of finding the missing value because we are uncertain of what exactly the number is that's why there can't be a = symbol.

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Everything has a wavelength (even we do). The DeBroglie wavelength is for things with mass such as a baseball or a human. The wavelength in the equation for speed of light is the wavelength for photons. These two wavelength are not the same thing. One is for objects with mass while the other one is ...

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How do you know which equations to use for number 33? I started of my using E=hv and got a very small number so I decided to look in the solutions manual and it showed that I should be using the De Broglie equation. When do you know you should use that equation?

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It could most likely be that you're plugging in things wrong into your calculator or you aren't using parenthesis. Because I multiplied 2 by 32 to cancel out the seconds and got 64 J. You the use the E= hc/wavelength equation and plug in what is given. You should get 4.7x10^-19 J photons^-1. After t...

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The answer is actually c. The extent of change is referring to the slope of the wave so when the frequency decreases the wave gets wider which means that the extent of change is decreases.

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It depends what kind of formula it was looking for. If it's molecular you shouldn't simplify, but if it's empirical then you should simplify.

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Rounding up would make the most sense. Rounding down would change the final answer from what it really is.

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Does anyone know if homework for outline 2 is due on the day we have the test about the high school review?

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