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Can anyone correct me if im wrong? This is basic basic basic basic basic basic biology, and i am just trying to refresh my memory and make sure that i am stating the correct facts 1) General concepts about tonicity ---- Lets say for example, we have a red blood cell exposed to solutions of different tonicity (hypo, iso, hyper) If the red blood cell was hypotonic to the solution, then the red's blood cell volume will increase, and ultimatey lysing the cell. If the red blood cell was iso to the solution, it will make no differenfce If the red blood cell was hyper to the solution, the cell would shrivel as water will leave the cell and thus losing volume in the red blood cell. 2) Lets say for example, the isotonic concentrations for the red blood cell's was exposed to different solution of increasing osmlarity but equal concnetration. If this was to happen, osmosis would be in equilibrium, since osmosis is only determnined only by a difference in total solute concentration, nut just spefically different solutions. 3) If polar molecules of increasing molecular weight was introduced to the red blood cell plasma membrane, then how would the rate of transport across the red blood cell membrane change? Well, first of all , it is very hard for a polar molecule to pass thru the membrane, let alone the size. So, the rate of transport across the red blood cell membrane would greatly be reduced. So am i stating the correct facts. Or are they any more stuff that can be added to my concepts? If im wrong anywhere, can you show me where and why? thanks

its the substitution of hydrogen on a benzene ring by molecular bromine acetanlide + Br2 ---> 4-Bormoacetanilide +HBr

If each molecule of acetanilide produces one molecule of hydroge bromide, what volume of HBr gas should be evolved from the reaction? So to solve this, ONE molecule of acetanlide will produce ONE molecule of hydrogen bromide... then, the molecular weight of hydrogen bromide produced will have a mass of 82 grams... Ok, am i doing this problem correctly so far? So what step do i have to go to next, i am confused on how to approach this problem, thanks

If you increase the substrate concetration, then the enzmatic reation will increas right? If you alter the pH affect of an enzymatic reaction,then the enzyme will denature right? are my concepts right ? also, If you pretreat an enzmye with high heat, how will it affect the rate?

how do we know if a molecule is optically active? does it have to do something about R,S configurations? I have no idea, what it is...and how to know whether a molecule is optically active or not thanks

what is a disadvantage of using diffential staining (dyes to increase the speciman's contrast) in light microscopes?

which of the following will most likely be disrupted by a change in pH? 1) hydrogen bonding 2) ionic bonding 3) hydrophobic interactions 4) disulfide bonds 5) neither -I'm pretty sure its not 1) and 2) since changing the pH won't affect the electronegativity of an atom...Pretty sure that its not disulfide bonds either, so from that im guessing that its hydrophobic interactions..am i right? or is my concept wrong? A nucleotide containing a purine, ribose, and a phosphate group could be a building block for? a) dna b) mRna c) tRna d) rRna e) b,c,d -Ok it is NOT A for sure, so im assuming that a nucleotide contaning a purine, ribose, and phosphate group could be a building block for all b,c,d....am i right ? or am i missing an important concept? A DNA molecule with 5'ATCGTAC3' = 3'TAGCATG5' right? If one thousaidn glucose molecues arrive in a cell, and the 1000 glucose molecules join together into a starch molecue, what changes occured with the synthesis of the starch molecule? -well this is an anabolic pathway since we are building something small into something bigger. So entropy decreases, since this is a non-spontaneous system. However, does the entropy of the universe decrease, or the entropy of the cell decrease? Dehydration syntehisis will decrease entropy within a system right? since its the formation of smaller molecules into bigger ones?

Why is it necessary to use a large excess of acetic adic in the prepartion of isopentyl acetate?

1) how many moles of h2 gas should be taken up by 1 octene in the courseof this reaction? CH3-(CH2)5-CH=CH2 -> (H2PtCl6) -> NaBH4, C2H5OH, HCL -> CH3-(CH2)5-CH2-CH3 Answer is 2 right??? 2) What volume does this correspond to at STP? How can i solve this part? 3) how many moles of molecular hydrogen are consumed per mole of the precatalyst (H2PtCl6) in order to convert it enterily to platinum metal? Isnt this 2 also?? what is the diff between this and the moles of H2 gas for the question #1? 4) How many moles of precataylst (H2PtCl6) are used in this reaction? Again is isn't this 2?? My answers don't seem right and i am still a little dubios before submitting them...am i misunderstanding a simple concept here? thanks

thx

ok, well here is the exact details of the problem: which fatty acid melts at the highest temperature (solid to liquid) (order from lowest to highest temp required to melt) Don't know how to draw on here, so i will just explain it to you 1) a 17 long hydrocarbon chain with a Carboxyl group attached at the end. Has no double bond 2) a 17 long hydrocarbon chain with a Carboxyl group attached at the end. Has 1 double bond 3) a 17 long hydrocarbon chain with a Carboxyl group attached at the end. Has 2 double bonds. My guess is that 1 requires least and 3 requires most temperature

how many diff polypeptides, each composed of 5 amino acids, could be synthesized using the 20 common amino acids? the answer is simply 20^5 right? if not, then can u please tell me what im doing wrong thx

okay, i understand how these reactions works and in which circumstances, but there are some general concepts that i am confused about. first of all, i know that in Sn2 reactions, generally weak bases are best as nucleophiles..but how can you know what a weak base is? for example, why is CH3CO2- a weak base (sn2 will predominate) and CH3CH2O- a strong base (E2 will predominate)? And..how can u tell what is an aprotic or protic solvent? for example, CH3OH is protic, but CH3CN is aprotic?

why is that a (Z)-2-chlorobutenedioc acid reacts MUCh faster than a (E)- configuration?

is it posssible to do a dehydrohalogenation of Cl using KOH, ethanol instead of NaNH2, NH3. for example: CH3-CH2-CL-C (double bond) CH-CH3 ----> CH3CH2C(triple Bond)CH On the midterm, i put KOH, ethanol, but i got it marked incorrect and the right answer was NaNH2, NH3...but when i read the book, it said either NaNH2, NH3 or KOH, ethanol is possible? somebody help me out here?

is it posssible to do a dehydrohalogenation of Cl using KOH, ethanol instead of NaNH2, NH3. for example: CH3-CH2-CL-C (double bond) CH-CH3 ----> CH3CH2C(triple Bond)CH On the midterm, i put KOH, ethanol, but i got it marked incorrect and the right answer was NaNH2, NH3...but when i read the book, it said either NaNH2, NH3 or KOH, ethanol is possible? somebody help me out here?

Suppose u let an acid sample sit for a week, does it lose weight after a period of time? and a base sample gain weight after a period of time? why is like this? and when a sample gains weight, the melthing point rises. is it because of the increased intermolecular forces? thanks

hi, i am tutoring someone tomorrow for the first time he is in 9th grade, learning geometry and english.. can anyone recommend me any good books? he never learned any geometry before. and for english, looking for good vocab building/ reading comprehension books thanks also any tips for me? my first tutoring

hey...i am screwed for life... i go to a UC and i got caught plagiarising on my english essay because i used my friends rough draft instead of my own, but the thing is its only the rough draft and the final draft is COMPLETELY different and in my own words, but still the proff turned it in to the board members and i got an automatic F for the class... This is my first time and i am fed cause i had my whole mind set in going to medical school...i studied extremely hard my whole freshman and soph year and maintaned a GPA of 3.8...and now cause of that one class, it would effect my gpa tremendously, and not to mention the added bonus of plagiarism getting put into my permanent profile would defniately eliminate my chances of going to a med school no matter how high my gpa or how high my mcats are..... how big is it if u plagiarise a rough draft?? im going to talk to them tomrorrow and i need to know what to say..thanks

Lets say you pipet into a 250 mL volumetric flask the following: 10 ml of 3e-4 M bromscresol green solution 25 mL of 1.6 M acetic acid (HC2H3O2) 10 mL of .200 M KC1 Solution and diluted to the 250 mL mark What is the molarity of acetic acid in this solution? Do you calculate the number of moles in the 25 mL solution since you know the molarity, then when u get the moles you find molarity over 250 mL? 2nd problem.. Lets say you have a solution with the following: 10 mL of 3e-4 Bromscresol green solution 10 mL of .160 M sodium acetate solution and diluted to 250 mL mark What is the mles acetate present? Do you calculate the # of moles over just 10 mL? Does the # of moles stay constant even though you add more volume? I think i heard that somewhere but not sure

If you put 25 mL of 1.6 M acetic acid, then, what is the molarity of acetic acid? Is it just 1.6 M x .025 L, or is it .160 M / .025 L? And..if you have 10 mL of 0.160 M sodium acetate , what is the moles of acetate in the solution? Is it .160 M X .01 L, im getting confused with the concepts involved in here

I know that Kw is equilibrium constant for water.. but what is Ka and Kb? I Is Ka equilibrium constant for acid and Kb equilibrium constant for Kb? If so how can u find those?? For example..here is an equation Kw = [OH-][H+] = 1e-14 What is the Ka and the Kb? Someone told me that Kw=Ka*Kb...is that true?

Why is HSO3- a stronger acid then H2SO3? And also, i know that When the size of an atom X increases, the H-X bonds decreases, meaning the strength of the acid increases since more H+ are ionized. But when when H-X are more electronegitive, doesnt it mean the bonds between the H-X gets stronger, meaning fewer H+ ionizes?? But this is not the case, the more electrongetive the bond between H-X, the acid strength gets stronger. Is my conceptual idea wrong? Also, lets say you have solutions of NH3, HCl, NaOH, and HC2H3O2 , all with the same solute concetrations. How would you know rank the pH of these solutions from highest to lowest or vice versa?

1) 1 Cu2O(s)+ (1/2)O2(g) -> 2CuO(s) Change in H = -144 kj 2 Cu2O(s) -> Cu(s) + CuO(s) Change in H = +11 Calculate the standard enthalpy of formation of CuO This is what i did, i reversed the 2nd equation so i get Cu(s) + CuO(s) -> Cu2O(s) by applying hess law, and Change in H becomes -11, then i added both equation 1 and 2 and got Cu(s)+(1/2)O2 -> CuO(s) after balancing, and the standard enthalpy becomes -144 kj - 11 kj which equals -155 kj.. Did i do this problem correctly? The following questions i got wrong and i have no idea why... 1) Calculate the S*net for the following reaction, Given the S* vales: Na(s)=51.4 e.u, H20 (l) = 69.9 e.u , Na+ (aq) = 60.2 e.u., OH- (aq) = -10.5 e.u. H2(g) = 130.6 Reaction = Na(s) + H20(l) <---> Na+(aq) +OH- + H2(g) This is how i solved it.. After balancing the equation, i got Na(s)+2H2O(l)<----> Na+(aq) +2OH- +H2(g)...And S*net = products - reactans, and after plugging it all in i got (60.2-2(10.5)+130.6) - (51.4 +2(69.9) which is -21.4 e.u. However, my answer was wrong and the answer was -12.6 e.u. How the heck did the professor get -12.6 ?? 2) For the process: benzene(l) --(1 atm)--> benzene (g), Change in Enthalpy = 30.5 kj/mol Change in S*vap=86.4 J/mol*K Assuming these vales are independent of T, what is the normal boiling point of benzene? This is how i solved it, since it is in 1 atm , it is simply Change in enthalpy - T*change in entropy= Change in G (free energy) = 0 0 = Change in H - T*Change in S After plugging it in.. 0 = 30,500 J/mol*k - T(86.4 J/mol*k) = 0 Solving for T you get 353degree Celcius..BUt that is not the answer, the answer is 80 degree celcius.. Where did i go wrong?

Hi, i am a 3rd year in General Chemistry, freshmen at a university, and i have a few problems that i've encountered along the way. These questions has been bugging me for a long time now and i really hope someone can fill in the holes and gaps in for me..anyways here they are 1) Lets say you have a .00035 L volume of .25 M Pb(NO2). What are the moles of Pb2+? This is my guess on how to do this. Since molarity = moles/volume...molarity of pb2+ = moles of pb2+/.00035 But how would i know what the molarity of Pb2+ is?? Can i just use .25 M Pb(N02) instead? Is it the same thing or am i missing something here 2) Lets say you put a test tube which in a hot bath for 30 seconds. Then you shake and stir the test tube and the solid precipitates. Is this an endo or exo thermic reaction? My guess is that its exo, because the surroundings are hot? But i am not sure, since the precipitate dissapears, wouldnt the equilibrium shift to the reactant side, meaning few products, which means endothermic?? 3) Lets say you have a pH of 0.10 M HCN solution which is 5.2. What is the [H+] and [CN-]. I know that pH = -log[H+], so to find the [H+] i would just take the antilog, but then how would i find the [CN-]?