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December 19, 2014

Posts by David


Total # Posts: 1,725

Biology - Hormones
estrogen is one
April 5, 2010

Chemistry
The Solvay process for the manufacture of sodium carbonate begins by passing ammonia and carbon dioxide through a solution of sodium chloride to make sodium bicarbonate and ammonium chloride. The equation for this reaction is H2O + NaCl + NH3 + CO2 → NH4Cl + NaHCO3. In ...
April 3, 2010

Chemistry
please hlep me out, thanks
April 3, 2010

Chemistry
Is that correct?
April 3, 2010

Chemistry
Barium sulfate, BaSO4 is made by the following reaction. Ba(NO3)2(aq) + Na2SO4(aq)----> BaSO4(s) + 2NaNO3(aq) An experiment was begun with 91.77 g of Ba(NO3)2 and an excess of Na2SO4. After collecting and drying the product, 62.3 g of BaSO4 was obtained. Calculate the ...
April 3, 2010

Chemistry
The Solvay process for the manufacture of sodium carbonate begins by passing ammonia and carbon dioxide through a solution of sodium chloride to make sodium bicarbonate and ammonium chloride. The equation for this reaction is H2O + NaCl + NH3 + CO2 ¨ NH4Cl + NaHCO3. ...
April 2, 2010

MATH
Let’s agree to say that a positive integer is prime-like if it is not divisible by 2, 3, or 5. How many prime-like positive integers are there less than 100? less than 1000? A positive integer is very prime-like if it is not divisible by any prime less than 15. How many ...
April 2, 2010

math
4. For the curve with y = -2x3 + x - 6, find: (b.) the gradient at the point (-1, -5) (c.) the equation of the tangent line at the point (-1, -5).
April 1, 2010

Math
Find the value(s) of x, so that f’(x) = 0 for the function f(x) = 4x3 – 6x2 – 24x.
April 1, 2010

Physics
(9.0e^9)(1)(1)/(1)^2 = 9.0e^9 (9.0e^9)(1/4)(1) = 2.25e^9 2.25e^9/(1/2)^2 = 9.0e^9 1/2*d
March 29, 2010

chemistry
One gram of TNT, C7H5N3O6, has 1.33 ´ 1022 hydrogen atoms. How many carbon atoms are there in 1.00 g of TNT?
March 29, 2010

calculus
(6+2y)/(3*sqrt(9-y^2)) = Ae^(kt) How do you show the steps to figure what y equals?
March 29, 2010

calculus
(6+2y)/(3*sqrt(9-y^2)) = Ae^(kt) How do you show the steps to figure what y equals?
March 29, 2010

economic
3. Consumer spending on durables falls, draw a graph to analyze the effects of this change in real interset. 4. The Canadian demand for Mexican Pesos is downward sloping and supply of pesos is upward sloping. Assume a system of flexible exchange rate between Mexico and Canada...
March 24, 2010

Physics
53
March 22, 2010

Chemestry
the solubility of a gas is 0.34g/L at STP. What is it's solubility at a pressure of 0.80 atm and the same temperature?
March 22, 2010

Chemistry
i dont no
March 22, 2010

Math
Carrie and Crystal live at a equal distances from school. Carries walks to school at an average rate of 3 miles per hour and Crystal rides her bike at an avergae rate of 9 miles per hour. It takes Carrie 20 minutes longer than Crystal to get to school. How far do Crystal and ...
March 20, 2010

History
This should actually be historian Richard Pipes
March 18, 2010

History
Why is historian Orlando Figes so against Lenin's actions - especially in the February and October revolutions
March 18, 2010

6th Grade Grammar
Thank you.
March 17, 2010

6th Grade Grammar
The sixth grade class *had wrote* several papers about the great sphinx. How should the words in the asterisks be written? A. had written b. has wrote c. correct as is
March 17, 2010

6th Grade Grammar
Thank you.
March 17, 2010

6th Grade Grammar
Present perfect, past perfect or future perfect. This month, we have learned about the great sphinx.
March 17, 2010

6th Grade Grammar
Present perfect or past perfect. The two have worked together to write a book.
March 17, 2010

6th Grade Grammar
Past perfect or present perfect. Raj has told the reporter about his new ideas.
March 17, 2010

6th Grade Grammar
Past perfect or present perfect. A reporter has interviewed him several times.
March 17, 2010

English
Its a letter to the editor we are analysing.
March 17, 2010

English
Language Analysis Please help me find persuasive techniques/statements in the following article.. I've never done this before, and I've "stewed" over the subject for the last couple of days, but I'm absolutely incensed that the Victorian Government will ...
March 17, 2010

math
how would you factorise a) 9x^2 - 49 b) 9x^2 - 121 c) 49x^2 - 25x^2 thankyou
March 14, 2010

Science 6th Grade
When the frequency of a note is twice the frequency of another, the notes are a(n) ______________ apart.
March 14, 2010

Science 6th Grade
Light, XRays, and radio waves contain _____________ with different amounts of energy.
March 14, 2010

computers
i need this decrypted if anyone can help that would be great 1b4a045c34a0573ca57657a1021dc171
March 12, 2010

chemistry
Most natural gas consists of about 90% methane, CH4. Assume that the solubility of natural gas at 20 C and 1 atm gas pressure is about the same as that of CH4, 0.02 g/kg water. If a sample of natural gas under a pressure of 20 atm is kept in contact with 1.00 *10^3 kg of water...
March 8, 2010

math
Nature's best wants to combine nuts they sell for $3.60 a pound with dried fruit they sell for $2.40 a pound to create a trail mix. How much of each snack should they use to make 10 pounds of trail mix that would sell for $3.30 a pound? Thank you!
March 7, 2010

Computer
OMG totally didnt see that, thank you!
March 6, 2010

Computer
This problem is a base conversion problem masquerading as a "word problem". You are responsible for controlling the stage lights at a small theater. The control box has control switches for 10 separate lights, and each switch can make its corresponding light off, red...
March 6, 2010

Chemistry-Equation
1.67 mol in a balanced equation there 6 mol of oxygen for every 1 mol of glucose; so ratio is 6 to 1. 10 mol oxygen/ 6 = 1.67...
March 5, 2010

math
I just have to tell if the are equal or equivalent or both, or neither. I think the answer is both but not sure
March 4, 2010

math
L,M,N,O and l,m,n,o are they equal, equivalent or neither? I can not figure this out please help.
March 4, 2010

geometry
When the number w is multiplied by 4, the result is the same as when 4 is added to w. What is the value of 3w
March 3, 2010

geometry
If p is an interger and 3 is the remainder when 2p+7 is divided by , then p could be what?
March 3, 2010

Math
A farmer has a dog, two geese and three bags of corn. He comes to a river. The boat to ferry him across the river can only hold the man plus two of his six possessions at a time. The farmer knows that if he is not right there the dog will eat a goose or a goose will eat the ...
March 2, 2010

math
(3n^4)^4 = 3d^3 x d^9 = 5e^4 x 6e^5 = thanks
February 28, 2010

Literature
In "A Pair of Silk Stockings," are a symbol of
February 27, 2010

11th grade
Factor f(x) = x^4 + x^3 – 8x^2 + 6x + 36 completely. Show all steps.
February 24, 2010

chemistry
When the glucose solution described in part A is connected to an unknown solution via a semipermeable membrane, the unknown solution level rises. Based on this information, what can be said about these two solutions? a.) The unknown solution had the lower concentration. b.)The...
February 24, 2010

chemistry
When the glucose solution described in part A is connected to an unknown solution via a semipermeable membrane, the unknown solution level rises. Based on this information, what can be said about these two solutions? a.) The unknown solution had the lower concentration. b.)The...
February 24, 2010

chemistry
nevermind i got it
February 24, 2010

chemistry
In the reaction A to products, A is found to be 0.489 M at t=72.0 s and 0.468 M at t=82.2 s What is the average rate of the reaction during this time interval? Do I take the Ln (0.468/0.489) = -0.04395 / 10.2 = 4.3 * 10^3. yet the comp says its wrong. i have to put it to two ...
February 24, 2010

chemistry
A 355g sample of a saturated solution of KNO3(s) in water is prepared at 25.0 degrees C. If 50g H2O is evaporated from the solution at the same time as the temperature is reduced from 25.0 to 0.0 degrees C, what mass of KNO3(s) will recrystallize? i have no idea where to start...
February 22, 2010

chemistry
Nope he has not responded
February 21, 2010

chemistry
How many grams of water would you add to 1.00 kg of 1.48 m CH3OH(aq) to reduce the molality to 1.00 m CH3OH. Use two sig figs. I get 4.8 * 10^2 grams and its not right. I want to put this up here again to see if there are any errors that could have possibly been made. (Putting...
February 21, 2010

chemistry
so would the answer be 4.8 * 10 ^ -2?? if its fewer?
February 21, 2010

chemistry
How many grams of water would you add to 1.00 kg of 1.48 m CH3OH(aq) to reduce the molality to 1.00 m CH3OH. Use two sig figs. I get 4.8 * 10^2 grams and its not right. I want to put this up here again to see if there are any errors that could have possibly been made
February 21, 2010

chemistry
How many grams of water would you add to 1.00 kg of 1.48 m CH3OH(aq) to reduce the molality to 1.00 m CH3OH. Use two sig figs. I get 4.8 * 10^2 grams and its not right. I want to put this up here again to see if there are any errors that could have possibly been made
February 21, 2010

Statistics
How do you know the p-value on megastat. On minitab It looks like it gets a different p-value than megastat. I got a number from megastat of 2.35E10 and on minitab it was 0.000.
February 21, 2010

math
Without finding the exact answer, select which of the following numbers is the best estimate of each sum or difference and justify your choices: -2/3, 0, 2/2/3. a. 1/9 + 2/5 – 1/3 – 3/4 I am confused on where to begin on this question.
February 21, 2010

chemistry
How many milliliters of glycerol, C3H8O3(d=1.26g/mL), must be added per kilogram of water to produce a solution with 4.85 mol % C3H8O3? Kinda lost -.-;
February 21, 2010

chemistry
If a hydrate of the formula decomposes when heated to produce HCl, what change would you expect to occur when a piece of blue litmus paper is held in the path of the vapor released? [Litmus paper is paper impregnated with an acid-base indicator that is blue in the presence of ...
February 20, 2010

chemistry
sorry would i multiply the moles of O2 by the 1(0.208) to get hte concentration which is proportional to the molarity?
February 20, 2010

chemistry
Okay, so this is how I think I should set it up? can you confirm it at least. Anyways I would try to find moles of O2 using ideal gas law (1.00 atm)(0.283)/(0.0821)(298) = n moles O2. then I would multiply 0.208 by the 1 L of water?? Then divide the moles of O2 / by L of water...
February 20, 2010

chemistry
Under an O2 pressure of 1.00 atm, 28.31 mL of O2 dissolves in 1.00 L H2O at 25 degrees. Determine the molarity of O2 in an aqueous solution at equilibrium with air at normal atmospheric pressure. The volume percent of O2 in air is 20.80 \%. (Have no idea how to go through with...
February 20, 2010

chemistry
oh. that's the complete opposite of what i thought. thanks
February 20, 2010

chemistry
An ideal liquid solution has two volatile components. In the vapor in equilibrium with the solution, the mole fractions of the components are (a) both 0.50; (b) equal, but not necessarily 0.50; (c) not very likely to be equal; (d) 1.00 for the solvent and 0.00 for the solute. ...
February 20, 2010

chemistry
Under an O2 pressure of 1.00 atm, 28.31 mL of O2 dissolves in 1.00 L H2O at 25 degrees. Determine the molarity of O2 in an aqueous solution at equilibrium with air at normal atmospheric pressure. The volume percent of O2 in air is 20.80 \%. (Have no idea how to go through with...
February 20, 2010

chemistry
nope. have to contact my teacher about this.
February 20, 2010

chemistry
How many grams of water would you add to 1.00 kg of 1.48 m CH3OH(aq) to reduce the molality to 1.00 m CH3OH? Ok...I got 480, and the systems says there's a rounding error. I did it again and I got 480. Someone help me?
February 20, 2010

biology 102
I've already done it, thank you. Was wondering if there were any other predictions.
February 19, 2010

biology 102
A prediction (educated guesses as to what the potential results may be) for each experiment listed below: 1) knee-jerk reflex 2) pupillary reflex (shield left eye, shine bright light into right eye, observe pupils) 3) 2-point threshold 4) temperature discrimination 5) ...
February 19, 2010

MATH
a<9. Not sure about the graph 3a<19+8 3a<27 a<27/3 a<9
February 17, 2010

Math
That's what I got.
February 17, 2010

Chemistry
Explain how to make a 1 Normal solution H3PO4.
February 17, 2010

Chemistry
What is the normality of 10 ml of an acid that took 25 ml of 0.25 N NaOH to reach pH 7?
February 17, 2010

Chemistry
You were using H3PO4 to make an acid solution. What is the equivalent weight of H3PO4
February 17, 2010

Chemistry
if you have 100 mg of CaCl2, how many moles of Cl do you have
February 17, 2010

CHEMISTRY
what is 0.00225 in two sigs? i hate sig figs -.-. thank you though.
February 12, 2010

CHEMISTRY
I calculated using the proportion and got 0.00025, and it was wrong. Then I used 9 ppb times 1000000 ml/ 1 ppb = 9000000, and used the proportion setup and still got it wrong.
February 12, 2010

CHEMISTRY
1.) A water sample is found to have 9.0 ppb of chloroform,CHCL3. How many grams of CHCL3 would be found in a glassful (250 ML) of this water?
February 12, 2010

chemistry
The second one is correct. Regarding the first one though, I calculated the grams to 6.8 g of C2H5OH. I don't quite understand the next step (regarding the density, etc)
February 12, 2010

College Math : Linear Algebra
Well I guess no one can help. :/ Oh well, I'll figure it out
February 9, 2010

College Math : Linear Algebra
Suppose A is a square matrix satisfying the equation A^3 - 2I = 0. Prove that A and (A - I) respectively are invertible. (the hint is to find an explicit equation for A^-1. To prove A is invertible, this is what I did although I don't that it's right: A^3 - 2I = 0 A(A^...
February 9, 2010

long-term
What other challenges do case workers face when working with placement of the elderly in long-term care facilities?
February 9, 2010

calculus
How large does N have to be in order to approximate the integral of cos(x^2) from 0 to 1, using the Midpoint Rule, with error at most 10^(-6)?
February 5, 2010

algebra
Find an equation of the porabola described. - Vertex(0,0);directrix x + 1 = 0
February 4, 2010

programming
I am working on a project called VB Auto Sales I am working in CH 2. I have just about completed the assignment but I am unable to group two separate sections. Assignment Modify the project from the Chapter 1 VB Auto Center case study, replacing the buttons with images in ...
February 4, 2010

Visual Basic
I should say I cannot get the special notices to work with the colors.
February 4, 2010

Visual Basic
I am working on a project called VB Auto Sales I am working in CH 2. I have just about completed the assignment but I am unable to group two separate sections. Assignment Modify the project from the Chapter 1 VB Auto Center case study, replacing the buttons with images in ...
February 4, 2010

Chemistry (Grade 11)
A radioactive sample of 141Cs has a half-life of 32.5 days. In a sample that contains 8.00*10^7 nuclei of 141Cs, how many beta particles per second will be emitted? A 19.8 B 1.7*10^6 C 71 076 D 1185 E 2.47*10^-7 The 141 supposed to be a superscript text, but firefox won't ...
February 3, 2010

6th Grade Science : Newtons First Law of Motion
Explain the idea of streamlining, as it applies to a skydiver.
January 30, 2010

6th Grade Science : Newton's First Law of Motion
Explain the idea of streamlining.\, as it applies to the skydiver. If you have the following textbook: Scott Foresman Science, 6th Grade good for you! Look on pages B102 - B105.
January 29, 2010

6th Grade math
Use prime factorization.
January 28, 2010

6th Grade math
The Odgen School marching band has 91 musicians. If there are 7 student musicians in each row, how many rows are there?
January 28, 2010

Maths
That would make more sense! Many thanks
January 28, 2010

Maths
Please could I have some guidance and advice on the following question? A multiple choice question has 4 options, A,B,C and D. The numbers of students choosing the options are in the ratio 3:1:2:14. I need to calculate the number of students choosing each option, (there are ...
January 28, 2010

shapes
if i had just a regular triangle and then it turned 90 degrees how would it look
January 27, 2010

11th grade math
secondary largest possible answre is Answer: x⋅(38-2⋅x)2 Answer: 8.06181572077
January 21, 2010

11th grade math
had this same probem for college pre-calculue couldnt solve B any other way but guess and check/logic x=4.5
January 21, 2010

6th Grade Grammar
Underline the form of to do or to have in the sentence. Today, many do their best to learn about Einstein's work. Also, what does the "to do" and the "to have" mean?
January 20, 2010

HSM210
Mrs Sue, Sorry to keep bothering you ! I have once more corrected the four answers . Do you mind checking them again. I so hate these assignments as I have such a hard time. Thank you so much for looking over my answers for me. 8. The victims’ rights movement developed ...
January 19, 2010

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