Thursday
March 30, 2017

# Posts by Val

Total # Posts: 187

algebra
help me understand how to solve this problem x+4y=17
May 12, 2010

Biology
A mutation has occurred in one chromosome of a spermatogonium. This mutation will show up in how many of the gametes produced from this cell? Choices: A. None B. Two C. All Four D. Cannot be determined I believe it is 2....If the mutation occurs in the spermatogonium it is ...
May 9, 2010

Chemistry
Could someone walk me through this problem? 6CO2 + 6H2O --> C6H12O6 + 6O2 partial pressure of CO2 is .26Torr, temp is 25 celsius, calculate volume of air to prouduce 10g glucose I keep getting confused with stoichiometry....my thinking: convert 10 g glucose to moles (which ...
April 24, 2010

Chemistry
Having some confusion with this question....I have the answers, just not able to reach them. A flask of volume 5L is evacuated and 43.8 g of solid N2O4 is introduced at 77K. The sample is then warmed to 298K during which the N2O4 vaporizes and some dissociates to form brown ...
April 24, 2010

this is copied correctly. the teacher wanted to keep it simple
April 19, 2010

if a rug's perimeter is 17cm and the area is 13cm, what are the reasurments for the length and width?
April 19, 2010

Chemistry
X(g) + 2 Y(g) + 2 Z(g) -->3 M(g) + 2 N(g) I've already found the orders for the following to be: X is 2nd, Y is 1st, Z is 0 and overall of course is 3. But I am confused about the below question. I initially guess that No it doens't occur in one step..but the ...
April 1, 2010

Chemistry
The hydrolysis of sucrose (C12H22O11) produces fructose and glucose (each C6H12O6). Two mechanisms are proposed: I) Step 1: C12H22O11 --> C6H12O6 + C6H10O5 (slow) Step 2: C6H10O5 + H2O--> C6H12O6 (fast) II) C12H22O11 + H2O--> C6H12O6 + C6H12O6 Would these mechanisms ...
April 1, 2010

chemistry
ooh nevermind i made a silly error...i have the answer now :)
March 31, 2010

chemistry
For the first-order reaction A => 3 B + C, when [ A]0 = 0.014 mol·L-1, the concentration of B increases to 0.017 mol·L-1 in 2.7 min. (a) What is the rate constant for the reaction expressed as the rate of loss of A? I found this to be .1923, which I know is ...
March 31, 2010

Chemistry
2A-->B+C given that the initial concentration of A is .022M and that at 69 s, the concentration of B increases to .0095M, what is the rate constant? i know I need to find the new concentration of A at 69s, but I am having trouble with findthing this. I thought it might be ...
March 31, 2010

Chemistry
use t= (1/ [ A]) - (1/ [A ]o) over k
March 31, 2010

Chemistry
i tried multiplying 7/8 and 8/9 by .69 each to find the respective initial concentrations of A to then use for the half life equation t=1/ k*[ A ]
March 31, 2010

Chemistry
The half-life for the second-order reaction of a substance A is 55.8 s when concentration of initial A = 0.69 M. Calculate the time needed for the concentration of A to decrease to the following values. (a) 1/8 of its original value (b) 1/9 of its original value
March 31, 2010

Chemistry
Oops, forgot to post the question. 2A-->B+C given that the initial concentration of A is .022M and that at 69 s, the concentration of B increases to .0095M, what is the rate constant?
March 31, 2010

Chemistry
I need to find the rate constant. I know that it takes 2A to make B, but I am mixed up on how to figure out how to find the concentration of A at 69s
March 31, 2010

Chemistry
When 442 mg of NO2 is confined to a 150. mL reaction vessel and heated to 300°C, it decomposes by a second-order process. In the rate law for the decomposition of NO2, k = 0.54 1/(M·s). A) what is the initial reaction rate? B) what is the reaction rate if the mass ...
March 31, 2010

Chemistry
How much time is required to electroplate 6.530 µg of chromium from a potassium dichromate solution, by using a current of 118 mA? I thought the ratio of e- to moles chromium would be 6/2 but I guess that is wrong? I am using t= nF/A I already made the proper conversions...
March 29, 2010

Chemistry
Determine the unknown quantity in the following cell at 298.15 K. Pt(s) | H2(g, 1.0 bar)| H+(pH = ?) || Cl -(aq, 1.0 mol·L-1) |AgCl(s), Ag(s), ΔE = +0.36 V. (DrBob) I still wasn't able to figure out the other one--I posted again after that one, but I know there...
March 29, 2010

Chemistry
Pt(s) | H2(g, 2.0 bar) | H+ (pH = 3.0) || Cl -(aq, 0.85 mol·L-1)) | Hg2Cl2(s) | Hg(l) I need to calculate the voltage for the cell. I have used 1E-3 M for my concentration of H+ given the pH=3 . I don't know how to incorporate the 2.0 bar into the nernst equation. I...
March 29, 2010

Chemistry
where does the .0592/2 come from? I've been calculating my RT/nF to be .025693/2 ....this is all so confusing...
March 29, 2010

Chemistry
Yes that's what I used to to try to find the voltage. But my answer is still coming out to be -.1833 which is incorrect
March 29, 2010

Chemistry
Pt(s) | H2(g, 2.0 bar) | H+ (pH = 3.0) || Cl -(aq, 0.85 mol·L-1)) | Hg2Cl2(s) | Hg(l) I need to calculate the voltage of the cell. I have a pretty good idea of how to use the Nernst equation for this, but am unsure if I am calculating the concentration of H+ correctly. ...
March 29, 2010

Chemistry
Nevermind, I made a silly mistake in my calculations...I figured it out :)
March 29, 2010

Chemistry
Pt | Fe2+ (6.4010-5 M), Fe3+ (0.0460 M) || Sn4+ (2.7010-4 M),Sn2+ (0.0750 M) | Pt i need to calculate the voltage of the cell. I know to use E=emf- (RT/nF)lnQ .... I think my problem is with setting up Q. I'm confused on what goes on top and what goes on bottom for the ...
March 29, 2010

Chemistry
Given the elementary reaction: 2 NOBr==>2 NO + Br2 k = 0.80 Which variables obtained for this reaction will produce a straight line? log[NOBr] vs. t [NOBr] vs. t [NOBr]2 vs. t 1/[NOBr] vs. t instinctively i would choose B, but I am not sure what my prof is getting at with ...
March 28, 2010

Chemistry
Gallium65, a radioactive isotope of gallium, decays by first order-kinetics. The half-life of this isotope is 15.2 min. How long would it take for 7/8 of a sample of this isotope to decay? 15.2 min 30.4 min 45.6 min 48.0 min I'm not sure how to do this. I initially tried ...
March 28, 2010

Problem Posting
I literally spent about 15 minutes retyping and rewording things....oh well
March 28, 2010

Problem Posting
trying to post a question, but it says I'm not allowed to post internet addresses--but I'm not. any ideas on this?
March 28, 2010

Chemistry --Need Help!!
Ive posted twice, but no one's answered yet...I could really use any kind of guidance--particularly for the 1st question :) 1)) The following two half-cells are paired up in a voltaic cell. How will lowering the pH affect the ƒ´E of the overall cell? ClO3-(aq...
March 24, 2010

chemistry
1)) The following two half-cells are paired up in a voltaic cell. How will lowering the pH affect the E of the overall cell? ClO3-(aq) + H2O(l) + 2e- ==> ClO2-(aq) + 2OH-(aq) Eo= 0.35 V I2(S) + 2e-==> 2I-(aq) Eo = 0.54 V A)dE will increase B)dE will decrease C)...
March 23, 2010

Chemistry
1)) The following two half-cells are paired up in a voltaic cell. How will lowering the pH affect the E of the overall cell? ClO3-(aq) + H2O(l) + 2e- ==> ClO2-(aq) + 2OH-(aq) Eo= 0.35 V I2(S) + 2e-==> 2I-(aq) Eo = 0.54 V A)dE will increase B)dE will decrease C)dE...
March 23, 2010

Chemistry
H1+(aq) + Fe(s) ==> H2(g) + Fe2+(aq) I am trying to balance this equation...but I am not sure how to balance the H's. I have the half rxns as e- + H+(aq) ==> H2(g) Fe(s) ==> Fe2+(aq) + 2e- I multiplied the reduc. rxn (top) by 2 so I could get rid of the electrons...
March 22, 2010

Chemistry
For the following electrochemical cell, what is the correct, balanced reaction? Cu(s) | Cu2+(aq) || Ag+(aq) | Ag(s) A. Cu(s) + Cu2+(aq) → Ag+(aq) + Ag(s) B. Cu(s) + Ag+(aq) → Cu2+(aq) + Ag(s) C. Cu(s) + 2 Ag+(aq) → Cu2+(aq) + 2 Ag(s) D. Cu2+(aq) + Ag(s) &#...
March 21, 2010

Chemistry
Use the data in this table to calculate the solubility of each sparingly soluble substance in its respective solution. (a) silver bromide in 0.066 M NaBr(aq) mol · L-1 I know how to do this one, found it to be 1.167E-11 which is correct. (b) nickel(II) hydroxide in 0....
March 19, 2010

Chemistry
Use the data in this table to calculate the solubility of each sparingly soluble substance in its respective solution. (a) silver bromide in 0.066 M NaBr(aq) mol · L-1 I know how to do this one, found it to be 1.167E-11 which is correct. (b) nickel(II) hydroxide in 0....
March 19, 2010

Chemistry
Suppose that two hydroxides, MOH and M'(OH)2, both have Ksp = 1.0 10-12 and that initially both cations are present in a solution at concentrations of 0.0036 mol · L-1. Which hydroxide precipitates first? I know MOH ppt's first...but am not sure how to approach ...
March 19, 2010

Chemistry
I am confused about where I am going wrong here... Suppose that 1.331 g of impure barium hydroxide is dissolved in enough water to produce 250. mL of solution and that 35.0 mL of this solution is titrated to the stoichiometric point with 17.6 mL of 0.0935 M HCl(aq). What ...
March 13, 2010

Chemistry
HA + OH- ---> H2O + A- .05 .03 0 0 "P"ut in -.03 -.03 +.03 +.03 "U"se up .02 0 .03 .03 "G"et Out It didn't line up well the first time. It makes sense to me...just a little tedious. If you have never seen this, what way have you taught ...
March 12, 2010

Chemistry
that simple and I've been working on this stuff for 5 hours! Thanks DrBob...I really wish my professor was able to break things down so clearly. Nice lady but she has a way of making me more and more confused... as for a PUG chart..maybe that's her own thing? It's ...
March 12, 2010

Chemistry
oops so nevermind I realized i made a mistake when calculating the molar mass. I found it to be 46 g/mol but I am still unsure how to find the pKA value. Thanks!
March 12, 2010

Chemistry
Suppose that 0.483 g of an unknown monoprotic weak acid, HA, is dissolved in water. Titration of the solution with 0.250 M NaOH(aq) required 42.0 mL to reach the stoichiometric point. After the addition of 21.0 mL, the pH of the solution was found to be 3.75. (a) What is the ...
March 12, 2010

Chemistry
I have another similar problem. I have calculated everything given (Correctly), but I can't seem to get the right pH for the stoichiometric point (I keep getting 7.16) Question: Suppose that 50.0 mL of 0.25 M CH3NH2(aq) is titrated with 0.35 M HCl(aq). Refer to table 1 and...
March 12, 2010

Chemistry
Nevermind I researched it for a few hours and finallly figured it out :)
March 12, 2010

Chemistry
Suppose that 30.0 mL of 0.20 M C6H5COOH(aq) is titrated with 0.30 M KOH(aq). Refer to table 1 and table 2. (a) What is the initial pH of the 0.20 M C6H5COOH(aq)? Using ICE i found to be 2.46 The rest I do not know how to set up or solve... (b) What is the pH after the addition...
March 12, 2010

algebra
y=.09(sq)-x+11.5 need to find y if x=10
March 11, 2010

Chemistry --Help 2! :)
Predict whether Fe(OH)2 will dissolve, precipitate, or do neither after: (a) water is added --> dissolve (b) Fe(OH)2 is added--> neither (c) Solid Fe(NO3)2 is added--> precipitate (d) Solid KNO3 is added---> neither I'm given the answers...but no explanation. ...
March 9, 2010

Chemistry--help!
Given the equilibrium: HCN(aq) + H2O(l) ←→ H3O+(aq) + CN-(aq) ΔH >0; Ka = 4.0 x10-10 What happens to the concentration of hydrogen cyanide [HCN] when the following stresses are placed on the system at equilibrium? NaCl is added ---> Stays the Same but ...
March 9, 2010

Chemistry
Consider the gas-phase equilibrium A ⇌ B. In a series of experiments, different initial amounts of A and B are mixed together, and the mixture in each case is allowed to come to equilibrium. Which one of these experiments would yield values for the amounts of A and B ...
March 8, 2010

Chemistry
Consider the gas-phase equilibrium A ⇌ B. In a series of experiments, different initial amounts of A and B are mixed together, and the mixture in each case is allowed to come to equilibrium. Which one of these experiments would yield values for the amounts of A and B ...
March 8, 2010

Chemistry
Could someone explain the reasoning for this? 6) Which of the following is a false statement about ALL reactions in equilibrium? a) Increasing temperature shifts the reaction toward the products in an endothermic reaction b) Temperature effects on the equilibrium do not depend...
March 8, 2010

Chemistry
where does the n come from in a compound such as n-butane?
March 8, 2010

geo
Which of the following describes an absolute location in China? 40ºN 100ºE 100ºN 40ºE 120ºN 50ºE 20ºS 100ºE
March 6, 2010

the length of a rectangular garden is 5 feet longer than its width. The garden is surrounded by a 2-foot-wide-sidewalk. The sidewalk has an area of 76 square feet. Find the dimensions of the garden
February 11, 2010

geometry
how will i get my answer
December 1, 2009

geometry
A spherical water tank has a diameter of 10 feet. How much water does it hold when half full (use 3.14 for , and round to the nearest hundredth)?
December 1, 2009

math
A typical Latino coffee farmer has fixed costs of \$10,000 per year. Under the old distribution system, the farmer is paid \$.40 per pound (U.S. weight measure) and the farmer’s variable cost per pound is \$.30. What is the farmer’s breakeven point in units (pounds) ...
November 15, 2009

high school
what is plumbing
November 5, 2009

p
other question Genenrally, inability to taste food is traceable to impairment of the sense of: A) smell B) sight C)Sound D) touch
October 21, 2009

p
so could be A than
October 21, 2009

p
i think that the best answer could be B
October 21, 2009

p
on this question can you help me please thanks At a restaurant, you bite into a stalk of broccoli and it tastes bitter to you. Your date thinks it tastes just fine. you may have: A) a sensitivity to tastes of bitter and salty, whereas your date has an elevated for sweet and ...
October 21, 2009

psychology
so it depends on whether they choose to pay atention to it.
October 21, 2009

psychology
Im not sure but i think that it depens on the distance of the stimulus
October 21, 2009

psychology
Whether you hear the dripping of sink faucets as the figure or the ground depends on: A) Its similarity to other noises B) your distance from the stimulus C) whether you choose to pay attention to it. D) the other tyoes of sounds you hear in the environment
October 21, 2009

ddddddd
perceotual illusions occur when our brain misinterprets sensory information or because of sencory: A) Overload B) Adaptation C) Deptivation D) patterns well this is the question
October 21, 2009

ddddddd
so the answer for the question es B
October 21, 2009

ddddddd
perceotual illusions occur when our brain misinterprets sensory information or because of sencory: A) Overload B) Adaptation C) Deptivation D) patterns i am not sure if the answer is A
October 21, 2009

psych
perceotual illusions occur when our brain misinterprets sensory information or because of sencory: A) Overload B) Adaptation C) Deptivation D) patterns i am not sure if the answer is A
October 21, 2009

psych
perceotual illusions occur when our brain misinterprets sensory information or because of sencory: A) Overload B) Adaptation C) Deptivation D) patterns i am sure if the answer is A
October 21, 2009

psych
thanks for the help
October 21, 2009

psych
habitually listening to loud music through headphones can result in loss of hearing in the: A)Organ of corti B) middle ear C) auditory nerve D) semicircular canals
October 21, 2009

biology
why would someone choose to propagate a particular plant for commercial purposes by using vegetative structures instead of seed?
October 8, 2009

healthcare
Identify and describe three causes for the increasing cost of healthcare and the impact it has on socity
August 1, 2009

We can use the web to get information, we don't have to use our school library. The two techniques are Scenario based planning and Project based planning.
April 22, 2009

Deliverable Length: 4-6 slides with in-depth speaker notes Today, many organizations and managers face new challenges everyday. One critical aspect of the challenges that managers lack in is within the planning stage. You have been asked by your manager to conduct a ...
April 22, 2009

English
Supposing that if A is equal to 1, b=2,etc. all the way to z equaling 26, what word or words starting with a B and a C total 100?
January 18, 2009

social studies)
We would be 50 separate countries
January 17, 2009

math
ln2 x ln2 x ln2 a + a + a (substitute) 3a
October 25, 2008

ETH 125
Bureau of Indian Affairs, National Congress of American Indians, and National Indian Gaming Association. What are organizations like these doing to mitigate povety and encourage prosperity
November 5, 2007

ETH 125
What are organizations like these doing to mitigate povety and encourage prosperity
November 5, 2007

college algebra
i need some help with this pleez! f(x+6) f(x)=3x^2-5x+3 if u could explain in steps that would be great! :) If f(x) = 3x^2-5x+3, then f(x+6) = 3(x+6)^2 + 5(x+6) + 3 Multiply that out and combine terms.
March 14, 2007

history
#5 = 14th and final point
February 1, 2007

Watershed?
Im in FLVS....most classes are the easiests but this one is pretty annoying and confusing with all the damn work.
November 1, 2006

Economics - Bonds
The Garraty company has two bond issues outstanding. Both bonds pa \$100 annual interest plus \$1,000 at maturity. Bond L has a maturity of 15 years and Bond S a maturity of 1 year. A). What will be the value of each of these bonds when the going rate of inters is (1) 5 percent...
October 28, 2006