The Official AP Chemistry Discussion Thread

<p>"How do you know that n is 6? n is like the moles of electrons "
Split up the reaction into half reactions and then find how many electrons it takes to balance the charges on both sides</p>

<p>"does a double bond count as 1 sigma AND 1 pi bond? "</p>

<p>yes</p>

<p>MC help!
The mass of element Q found in 1.00 mole of each of four different compounds is 38.0 grams, 57.0 grams, 76.0 grams, and 114 grams, respectively. A possible atomic weight of Q is:
(A) 12.7
(B) 19.0
(C) 27.5
(D) 38.0
(E) 57.0</p>

<p>The answer is B. I don’t understand this and I know it should be really easy! Help?</p>

<p>Where did you pull that from? I have no clue about how to solve that.</p>

<p>I think calorimetry is a pretty safe bet, considering it’s thermo, but how do you do a calorimetry lab?!</p>

<p>look at your periodic table, 19.0 is the only real atomic weight</p>

<p>are there answers to the 2004 multiple choice?</p>

<p>it’s from the 1989 mc. so you’re saying it’s diatomic? F2?</p>

<p>atomic weight is just one atom and so it is f which is 19.0</p>

<p>19.0 is the only one of the masses that can be divided EVENLY into the others. =]</p>

<p>what is a coordination complex?</p>

<p>ok thanks that seemed tricky</p>

<p>In chemistry, a complex, also called a “coordination compound” or “metal complex”, is a structure consisting of a central atom or molecule connected to surrounding atoms or molecules. Originally, a complex implied a reversible association of molecules, atoms, or ions through weak chemical bonds.</p>

<p>Anyone wana review sigma/pi bonds? Electron affinity, atomic radius and the likes?</p>

<p>I think i understand most of the colligative properties. but just for reassurance, can you explain the trends of electron affinity? That’s the only tricky one.</p>

<p>Come on guys keep this thread alive for the nx 10 hours.</p>

<p>I’m hoping for a 4 on this test… I’m good on most things except LeChatelier’s and Atomic Structure/Bonding/IMFs… which is a pretty big chunk of the test! Guess I gotta study…
Anyway my predictions…</p>

<p>1) Ka or Kb
2) Gases (Finding Molar Mass from Vaporizing a Compound)
3) Thermo
4) Net Ionic Reactions
5) Electrochem (Electrolytic Cells)
6) VSEPR/Bonding/Atomic Structure</p>

<p>We better keep this alive! The AP Bio kids are all going “whew this test was easy” yet their review thread is much larger than ours!</p>

<p>JinKoroshiku - Le Chatelier’s Principles apply to almost every topic, it’s kinda nuts. Especially Equilibrium and Solutions. Also, how did you decide your predictions? No stoichemetry? Just wondering.</p>

<p>aznjunior - a coordination complex is the “charge” part of a complex ion, like Cu(NH3)4+. Since Cu2+ is a ligand, its coordination complex # are usually double of a ligand’s charge, so you add it to the charge of the lewis base (NH3) to get the total complex ion coordination complex.</p>

<p>this may have been discussed but what is the approx. # of MC you must get right to get a 4 and 5? and do you all actually get through all 75? i’m really slow…90 minutes isn’t enough time for me to finish</p>

<p>50/75 raw score is enough to get 70% - 5. I would use a two pass system (doing all the ones you know first, then going back later) in this situation. What topics do you think you’re weak on for MC? I’m in the same situation =/ Apparently the big hitters are stoichemetry, acid base, solutions, electrochem, and the other big topics.</p>

<p>Wish all of you guys and myself good luck and get a 5!!!
God bless!!!</p>

<p>i’m weak on electochem and thermochem…some of these questions are so random</p>