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Posts by Devron

Total # Posts: 1,047

math
That is correct. 200 + [0.15 * (2,500-1,000)] = ?

math--typo
200 + (0.15 * 2,500) = ?

Math Check
Thanks

Math Check
Thanks, so this falls under induction by reasoning, if I'm not mistaken?

Math Check
For each integer n>1, let A(n) denote the sum of the integers from 1 to n. For example, A(100)=1+2+3+ +100=5,050. What is the value of A(200)? A.)10,100 B.)15,050 C.)15,150 D.)20,100 E.)21,500 I know that the best answer choice is D, but the explanation that I was provided ...

Biology
a.The monomers that make up a protein vary whereas the monomers that make up a complex carbohydrate are all the same. --This is mostly true, but I would suggest that you give a couple of examples, such as fatty acids, or a short truncated protein. b.Proteins function as energy...

Chemistry
Things to keep in mind: Molarity=Moles/Volume (L) HNO3=63.01g/mol 69.5%=0.695 and 1cm^3=1mL=10^-3L Convert Density from g/cm^3 to g/L: 1.42g/cm3*(1cm^3/10^-3L)=1420g/L Calculate the amount of pure acid: 1.420g/L*(0.695)= mass of pure HNO3 in g/L Since the molar mass of HNO3=63...

Math Check
Got it. I was totally overthinking this.

Math Check
I know that, which is why I thought the answer was no, but then I was told that the answer was yes. I couldn't simplify nor reason it any further than what I have submitted. If you can show how to do it, it would be greatly appreciated; the problem is kind of bugging me.

Math Check
I thought is was no. When asked this question by someone, I could not get the left side to look like the right. x^2+ x(6)^1/2+3=x^2 +3 How does this simplify any further?

Math Check-Typo
Is the following statement true: (x^4+6x^2+9)^1/2=x^2+3

Math Check
Is the following statement true: (x^4+6x^2+9)=x^2+3

Science
The pull of electrons is the main reason. The pull of the lone electron of hydrogen by oxygen shortens bond length; this is easily seen by looking at the electronegativity difference between oxygen and hydrogen. Although alcohol also contains a OH bond, the OH is bonded to a ...

Organic chemistry
I'm not sure, but I do not think that a reaction would occur. ALCl3 usually acts as a catalyst, and would just form an ionic bond with the oxygen on the carbonyl of the compound; there isn't another reactant to form some other compound.

chemistry
First, determine the molarity of KHC2O4: 0.717g*(1 mol/128.12g)=moles of KHC2O4 18.47 mL=0.01847L Molarity of KHC2O4=moles of KHC2O4/0.01847L The reaction is a 1 mole to 1 mole reaction. Therefore, moles of KHC2O4=moles of NaOH. So, Molarity of KHC2O4=Molarity of NaOH ***...

Physics
I hope someone validates this answer since I don't play around with these concepts all of the time, but here is my response. The force that the block exerts down the ramp is the following: Fof block=mg*Sin(30) Fof block=(4.0kg)*(9.8m/s^2)*(0.5)=19.6N Force of Static ...

Chemistry 2--Dr.Bob222
I initially made the same mistake, which confused me a little. I reread the question and saw that the questioner and I, both, may have initially overthought the question. --Best

Chemistry 2
To the questioner: I apologize about the typos. I meant to say solve for Delta*G and not just Delta. My post should have said the following: DeltaG=DeltaH-DeltaS*T Where DeltaH=-220kJ/mol DeltaS=-136.76J/K=-0.13676kJ/K T=426K and DeltaG=???

Chemistry 2---Dr.Bob222
The key part of the equation states that ASSUME that DeltaS and DeltaH DOESN'T Change much, meaning that it is safe to plug and chug. ***To the questioner: change -136.76J/K to kJ, which should be -0.13676kJ/K

Chemistry 2
DeltaG=DeltaH-DeltaS*T Where DeltaH=-220kJ/mol DeltaS=-136.76kJ/K T=426K and Delta=????

Ap chem
It would increase the rate of the reaction. Looking at the equation should allow you to notice this. In general there are three factors that can affect the rate of a reaction: 1.) reactant concentrations 2.) catalysts 3.) temperature

Chem
You can use an equation or you could just do it intuitively; I choose to do this one intuitively. 1.0mg =12 hrs 2.0mg=10 hrs 4.0mg=8 hrs 8.0mg= 6hrs 16.0mg=4hrs 32.0mg=2hr 64.0mg=0hrs So, you will initially need 64.0mg of 55Cr to have a minimum of 1.0mg after 12-hours.

Chem
I think that you need more information then what you are providing for someone to be of any help.

chemistry - kinetics
Use the following equation: Ln(k2/k1)=Ea/R[(1/T1)-(1/T2)] Where k1=0.0796 M−1*s−1 k2=0.0815 M−1*s−1 R=8.314 J/mol K. T1=273+737=1010K T2=273+947=1220K and Ea=???? Solve for Ea: Ea={R*[Ln(k1/k2)]}/[(1/T1)-(1/T2)]

science
I just noticed that I messed up. D is an answer that shouldn't have eliminated, and to be honest, I believe that it is the best answer choice.

science
The purpose of the endocrine system, which secretes hormones, is to control growth and development. Which of these answer choices best fits that description? I will eliminate two answers for you -- answer choices C and D-- to give you a 50/50 chance

PHYSICS
I apologize about that. I should have thought about it for more than 3 seconds. The answer is in the directions: the puck travels only one-half the distance Conservation of mechanical energy says that Work=kinetic energy F*d=1/2mv^2 m*a*d=1/2mv^2 masses are the same and cancel...

PHYSICS
I wouldn't know how to solve the problem either because you are missing some information.

General Physics--Typo
V3=9.82m/s

General Physics
Use the following relationship: M1V1 +M2V2= M3V3 Where M1=5.00kg V1=12.0m/s M2=6.00kg V2=8.00m/s M3=5.00kg+6.00kg=11.00kg and V3=??? Solve for V3: (5.00kg*12.0m/s)+(6.00kg*8.00m/s)=(11.00kg)V3 V3=108kg*m/s/11.00kg V3=9.82 N s

Heat
The same way that I showed you how to do the other one, but just convert 8.08g of H2 to moles: 8.08g of H2*(1 mole/2.02g)=??? moles

Enthalpy
Assuming O2 is in excess: 2 moles of MgO=2 moles of Mg=1 moles of O2 So, 4 moles of Mg*(-1203kJ/2 moles of Mg)=???

Chem
14 H^+ + 2 Mn^2+ + 5 NaBiO3 --->5 Bi^3+ + 2 MnO4^- + 5 Na^+ + 7 H2O Here is the the balanced reaction (Oxidation and Reduction) 34.2MgSO4=0.0342g of MgSO4 0.0342g of MgSO4*(1 mole/120.366 g)= moles of MgSO4 The equation shows that 2 MnSO4 moles=5 moles of NaBiO3 So, moles ...

Chemistry
I wouldn't tackled it this way, and you are free to not use what I am telling you because I can not be 100% positive about the answer. However, I would go this route: q=mct where q=44,000 kJ=4.4 x 10^4 kJ=4.4 x 10^7 J c=8.37 J/g*C t=110 C-95 C=15 C and m=??? Solve for m: m...

chemistry
I am not sure, and someone can come along after I am done and check what I am telling you, but I believe you are missing some information like the temperature change. The question seems to be incomplete.

chemistry
I didn't fully read this question; I was wondering what Dr.Bob222 did. He is correct: 4.0mL of of Cl2 will be used meaning that there will be no Cl2 left at the end of the reaction, but 3.0mL of H2 gas will be left after the reaction is complete. However, I'm not sure ...

chemistry
The reaction is as followed: H2 + Cl2 ----> 2HCl You can treat this as a limiting reagent problem, where Cl2 is the limiting reagent. 1 mole of Cl2=2 moles of HCl or 1mL of Cl2= 2 mL of HCl 4.0mL of Cl2*(2 mL of HCl/Cl2)= 8mL of HCl (g)

chemistry-typo
I meant to say that the answer to part 2 isn't the answer to part 1.

chemistry
I agree with DrBob222 and then I don't agree with him: I agree that the 2nd part that he gave you in his last point is correct, but the answer to part 2 isn't the answer to part 2. I agree that it should because adding these two concentrations of acid together doesn&#...

chemistry
The first question asks for the MOLARITY of the solution after adding the two together; the second question asks for the molarity using the DENSITY. You will get two different answers. Also, the acid that is given is H2SO4 and not HCl. The molecular weight that Drbob222 used ...

BIO HELP PLEASE!!!
Because the virus doesn't affect the rest of the cell types that it targets until a stress or an environmental factor causes reproduction and lysis; it remains dormant until it receives it's que to begin.

Chemistry
First, convert mL to L: 20mL=0.0200L and 30.0mL=0.0300L Solve for moles: M=moles/Volume (L) so, moles=M*Volume(L) New Molarity=Total moles/Total Volume M=[(0.0200L)*(3.0 M)+(0.0300L)*(2.0M)]/(0.0200L+0.0300L)

chemistry
HCl is a strong acid so, determine the pH: pH=-log[HCl] pH+pOH=14 14-pH=pOH Since pOH=-log[OH^-] 10^-(pOH)=[OH]

science
I don't see questions 1 and 2, but if you are referring to questions 4 and 5, then I believe that answer choice A is the best answer choice for number 4 and I agree with your answer choice for number five as well.

chemistry
Write out the reaction: ZN + 2 HCl --> ZNCl2 + H2 Covert g of H2 gas produced to moles: 0.15g of H2*(1 mole/2.016g)= moles of H2 moles of H2=moles of Zn moles of Zn*(65.37g/mol)= g of Zn Answer contains two significant figures Conversely, this could have just been combined ...

Scientific Notation
3^4=??????

Chemistry
if the volumes of the weak acid and its conjugate base are equal than the pH=pka of the solution. You know this by looking at the Henderson–Hasselbalch equation. pH=pka+log[A^-]/[HA] Where A^-=NaNO2 and HA= HNO2 Since the concentrations are equal, the above equation ...

biology
ATP is the energy source for all cells, so that answer is ruled out. C is also ruled out because although it is a neurotransmitter, it is activated to usually cause an emotional response; Glycine is one of the simple amino acids that doesn't act on taste buds -- as far as ...

biology
The control of skeletal muscle is voluntary, which means that you can control its' movement. However, the movement of blood through the body is not voluntary, which means you can not control it. So no, A can not be the answer.

Biology
No, that is why they are called memory B-cells. They remember that specific infection and respond accordingly.

Chemistry
Used the following equation and plug in a couple of variables for T and see what you get. ΔG=ΔH−TΔS Remember, if ΔG is negative then the reaction is spontaneous, if positive, than the reaction is not spontaneous, and if equal to 0 is at equilibrium.

Chemistry
I am not sure I understand what you are saying, but the number that number seems to be the Ka value for phosphoric acid. pH=pka+log[A^-/HA] let pka=-log[Ka] Ka=6.2 x 10^-8 pka=-log[Ka]=7.21 A^-=0.335 HA=0.335 To help you out a little bit: The concentrations are equal, so the ...

Chem
0.750g of MgCl2*(1 mol/95.211g)=0.007877 mol of MgCl2 *****1 mol of MgCl2=2 moles of AgCl This is the key and is where your error lies. 0.007877 mol of MgCl2*(2 mol of AgCl/MgCl2)=0.01575 moles of AgCl 0.01575 moles of AgCl*(143.32 g/mol)=2.26g of AgCl Best

Biology
Cross it with a wrinkled seed. rr=wrinkled. Rr x rr Progeny: 1 Rr 1 rr RR x rr Progeny will all be Rr and will all be Round

Chemistry
Use the gas law equation and solve for n (moles): PV=nRT Where P=3 atm V=5.00L R= 0.0821 liter·atm/mol·K T=292K and n=??? Solve for n: n=PV/RT n*39.95g/mol=mass of gas ***You can perform the rest.

Cara-Chem
Remember, pH=-log[H^+] so, pH=-log[x]

Cara-Chem
I made a bobo, which may lead to some confusion. Here is my post revised: You don't need it. Just calculate the new molarity of the acid after addition of NaOH, and then determine the molarity of the acid in solution. How many moles of propionic acid are left after ...

Chemistry
I do apologize about that. I totally forgot about the salt. Ignore the x for the salt in the setup that Dr. bob222 gave you because we are assuming that dissociation is small and solve for x. When I gave you the setup, I ignored the x in the denominator assuming dissociation ...

Chemistry
You don't need it. Just calculate the new molarity of the acid after addition of NaOH, and then determine the molarity of the acid in solution. How many moles of propionic acid are left after addition, of the strong base? In this case, Molarity=moles 1.29 x 10^-2 M=1.29 x ...

Chemistry
I'm going to assume that this is mass/volume percent: m/v%=(g/mL)*100 6.0%=(x g/50mL)*100 (6.0/100)*50=x g Solve for x g Which should be 3g, I believe.

chemistry
HNO3 is a strong acid, so this is fairly straight forward question. Calculate the new molarity of the acid after being mixed with H2O: 0.01M*0.005L= moles of HNO3. moles of HNO3/(0.005L+0.05L)= Molarity of HNO3 after addition of water. Since this is a strong acid, you can just...

chemistry
You need to pay attention to your units. The temperature for heat capacity is in given with C not K. You have to use C as temperature and not K. Also, I have no idea what the problem is asking; all I see is numbers, so I really can't check, nor can anyone else.

Chemistry
Check the units. That is where the error is. q=mct where m=10.0kg=10,000g or 10 x 10^3g c=0.385 J/g*C and T=65 C - 25 C=40 C q=(10,000g)(0.385 J/g*C)(40 C) q=15.4 x 10^4 J We agree, but I have 154,000J and not KJ. You have to convert 154,000J to KJ. 154,000J =15.4 x 10^1 KJ= ...

physics
a.) m1v1+m2v2=m3v3 Let: m1=1300g=1.3kg v1=0m/s m2=39g=0.039kg v2=290m/s m3=1.339kg *** addition of m1 and m2 and v3=??? Solve for v3: (1.3kg+0)+(0.039kg+290m/s)=(1.339kg)v3 v3=[(1.3kg+0)+(0.039kg+290m/s)]/1.339kg v3=1.3+11.31/1.339 v3=9.41m/s b.) Fnet=F(block)-F(friction) Let ...

Organic Chem
The answer may be answer choice B. Answer choice A, in my opinion, is the best answer choice. However, adding more benzene would DECREASE the amount of undesirable side products, but would NOT prevent it. Adding more benzene would not solve the problem, but it would help.

Organic Chem
I believe the best answer choice is A. Using more Benzene wouldn't do anything to prevent the formation of undesirable side products. Distillation will remove H2O and wouldn't do anything as well; I do not believe that H2O will react with Toluene, but it will react ...

Chemistry--Typo
I meant to say solve for Ka and not x.

Chemistry--Typo
Typed something out of habit. plug in the value for x and solve Ka: I apologize about that.

chemistry
HA ----> A^- + H^+ Ka=[A^-][H^+]/[HA] ....HA........A^-....H^+ I ..0.22 ......0......0 C..-x..........x.......x E.0.22-x....x.......x Ka=[x][x]/[0.22-x] Let x=0.22*(0.209) Solve for x:

Chemistry
I think this has to do with the orbital stuff that you learn in organic chemistry, and/or physical chemistry, or some other chemistry courses. I think you should go with A, collection of balloons. This is what that orbital stuff looks like in a book; I hated that orbital stuff...

Chemistry
You have to do your own work. Maybe just post what you think it is and why.

chemistry
The nucleus contains what? Positively charged protons and neutrons, so what is it likely to attract? Therefore, what is shielded? I think you may be on to something.

Chemistry
It doesn't detect hydrogen nor helium, so that only leaves one answer.

chemistry
I've told you enough.

chemistry
NMR is usually abbreviated as 1H NMR. So, I'll let you answer that question as well.

Chemistry
The word in electron in photoelectron spectroscopy should eliminate answer choice C. Can you excite core electrons? Look for images to see how this works.

chemistry
That last part of my sentence should have said, "D should be answer choice C."

chemistry
I think the answer is A, but I am not sure. I believe that Low frequency radio waves are used, which eliminates answer choices B and D, which should be answer choice C. I have used NMR is performing research, but I never had to know the type of frequency used nor did I care to...

Chemistry
Density=mass/volume Density of Bromine=586g/188 mL ***Answer contains 3-significant figures

chemistry
42.45-mL=0.04245L 0.8743 g sample of KHP*(1 mol/204.22 g)= moles of KHP moles of KHP=moles of NaOH Molarity (M)=moles of NaOH/0.04245L **Answer contains 4-significant figures

Chemistry
The retention time looks good for A, except that you should have 0.792-- one more significant figure, so I will move on to the next problem. This is only for A, and I think you can perform the rest after I am done. To solve for the distribution constant, perform the following...

Chemistry
First, determine the number of moles for CH3COOH (HAc), CH3COONa (Ac^-), and HCl Molarity=moles/Volume (L) Moles=molarity*volume (L) Moles of HCl=0.1M*0.010L=x Moles of HAc=1.0M*0.025L=y Moles of Ac^-=0.5M*0.025L=z Calculate the pH of the buffer: pH=pka+log[A^-/HA] Where pka=4...

Chemistry
Answered this for you in your subsequent post.

SCIENCE--Typo
Initial velocity=time*deceleration=4s*9.8m/s^2=39.2m/s

SCIENCE
It takes the arrow 4 seconds to reach the top and 4 seconds to reach the bottom. Solve for height: d=1/2at^2=1/2(9.8m/s^2)*(4s)^2=78.4m Initial velocity=time*deceleration=4s*9.8m/s^2=39.2m

Physics
Doesn't matter when you convert it, but the units have to be the same once you perform the calculations. Conversely, you could have just converted the acceleration from m/s to km/h. I thought it was easier to do by converting the velocity. Best.

Physics
Then the answer should be answer choice A, and not B. Acceleration=change in velocity/time Change in velocity/acceleration=time So, 110km/h=30.56m/s and 70km/h=19.44m/s (30.56m/s-19.44m/s)/3.8m/s=t t=11.12m/s/3.8m/s t=2.9s

Physics
I hope the speed is km/s You will have to convert km/s to m/s Acceleration=change in velocity/time Change in velocity/acceleration=time So, 100km/s -70km/s/3.8m/s=t t= about 8 s; I don't agree with any of these answers. 2.) You are correct.

Chemistry
45.4g of H2O*(1 mole/18.00g)=moles of H2O moles of H2O*(moles of Fe(C2H3O2)/3 mole of H2O)=moles of Fe(C2H3O2) moles of Fe(C2H3O2)*(232.98 g/1 mole of moles of Fe(C2H3O2))= g of Fe(C2H3O2)

Chemistry
I'm not sure that I understand your question. We don't need to calculate the molarity because the volumes are the same, and will cancel out. Therefore, you can use mole amounts for each of the species; I hope this answers your question. The concentration of each ...

Chemistry---Typo
*****Correction of last part: Use this variation of the Henderson-Hasselbalch equation and solve for pH: pOH=pkb+log[BH/B] Let B=y** BH=x** pkb=-log(5.2 x 10-4) and pOH=??? Solve for pOH: After solving for pOH, solve for pH: pH+pOH=14 pH=14-pOH

Chemistry
No ICE chart is needed; you just have to look at what is going to happen when the HCl is added. HCl + CH3NH2 ------> CH3NH3^+Cl^- So, the addition of HCl will convert some of the CH3NH2 to CH3NH3^+Cl^- and decrease the amount of CH3NH2. First, figure out the amount of moles...

To Devron
My concentration was in biochemisty, but my research was done in an organometallic chemistry laboratory studying the efficacy of micruflidic devices on the determination of enantiomers generated from zirconium and niobium Lewis-acid cataylst using GC's and H NMR. So, I'...

To Devron
I saw it, and did not understand it as well, which is the reason that I left it alone after looking at your reply.

chemistry
I don't know this article by heart, nor have I ever read it. I doubt that Dr. Bob222 hasn't read nor knows this article as well. And I doubt that you will get anyone on this forum to find and access this article to check your work. Best and good luck.

Chemistry
I like that you told the student that chemistry is never dull--classic.

Chemistry
Chemistry and physics are both fun subjects. Do you need to understand math? Yes. Does it compare to physics? Yes. However, the math is more tedious than it is in chemistry, and at times, requires more steps, and requires a different type of conceptualization to apply the math...

Chemistry
I don't want to waste my time doing a lot of typing if this is not what you need.

Chemistry
This is a confusing question that is poorly worded. So, I am not sure what your professor wants you to do. The confusing part, to me, is from pH 1 to 13 with 0.4M NaOH. However, this is what I think you are suppose to do: determine the volume of 0.4M NaOH added to reach the ...

Chemistry
This is a confusing question that is poorly worded. So, I am not sure what your professor wants you to do. The confusing part, to me, is However, this is what I think you are suppose to do: determine the volume of 0.4M NaOH added to reach the equivalence point for H3PO4 and ...

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