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September 18, 2014

Posts by K


Total # Posts: 750

chemistry
A solar heating specialist is considering paraffin as a possible solar heat collector. How many kilograms of paraffin would be needed to collect as much energy as 4.73 x 10^3 kg of water? The specific heat of paraffin is 2.90J/gxC. Hint: Assume the same temperature change.
January 15, 2012

chemistry
A solar heating specialist is considering paraffin as a possible solar heat collector. How many kilograms of paraffin would be needed to collect as much energy as 4.73 x 10^3 kg of water? The specific heat of paraffin is 2.90J/gxC. Hint: Assume the same temperature change.
January 15, 2012

trig
find the exact value of sin(u+v) given that sin u=3/5 and sin v= 15/17
December 18, 2011

Physics
A race driver has made a pit stop to refuel. After refueling, he starts from rest and leaves the pit area with an acceleration whose magnitude is 5.4 m/s2; after 3.7 s he enters the main speedway. At the same instant, another car on the speedway and traveling at a constant ...
December 13, 2011

Physics
A jetliner, traveling northward, is landing with a speed of 66.5 m/s. Once the jet touches down, it has 766 m of runway in which to reduce its speed to 13.1 m/s. Compute the average acceleration (magnitude and direction) of the plane during landing (take the direction of the ...
December 13, 2011

Physics
In getting ready to slam-dunk the ball, a basketball player starts from rest and sprints to a speed of 11.1 m/s in 2.30 s. Assuming that the player accelerates uniformly, determine the distance he runs.
December 13, 2011

Physics
A race driver has made a pit stop to refuel. After refueling, he starts from rest and leaves the pit area with an acceleration whose magnitude is 5.4 m/s2; after 3.7 s he enters the main speedway. At the same instant, another car on the speedway and traveling at a constant ...
December 13, 2011

math
did you get the answer to this?
November 23, 2011

physics
a 1.29 kg ball is connected by means of two massless strings to a vertical, rotating rod. The strings are tied to the rod and are taut. The tension in the upper string is 38 N. The length of both strings is 1.70m and the distance between the strings on the rod is 1.7.
November 20, 2011

Math
In this problem, x cubed = 12y...how do you solve to determine if this is direction variation or not?
November 15, 2011

algebra
Katydid population is modeled by N(t) = 50 / 1+9e^ -.33t where t is number ofyears and N(t) is population is thousands at time t. when will katydid population reach 40,000? I somehow got a negative log, producing an error so i can't go any farther. Please help.
November 8, 2011

7th Math
what would you do than with 5/8 ??
October 27, 2011

7th Math
A plumber must bend a piece of tubing twice, allowing 5/8 inch for each bend. use the total of 12 1/2, 16 3/4, and 18 3/4. To find the total length of tubing needed?
October 27, 2011

Physics Honors
8.7s,56.55m
October 23, 2011

Finance
Tuttle Buildings Inc. has decided to go public by selling $5,000,000 of new common stock. Its investment bankers agreed to take a smaller fee now (6% of gross proceeds versus their normal 10%) in exchange for a 1-year option to purchase an additional 200,000 shares at $5.00 ...
October 20, 2011

Finance
Rainier Bros. has 12.0% semiannual coupon bonds outstanding that mature in 10 years. Each bond is now eligible to be called at a call price of $1,060. If the bonds are called, the company must replace them with new 10-year bonds. The flotation cost of issuing new bonds is ...
October 20, 2011

Finance
Thompson Enterprises has $5,000,000 of bonds outstanding. Each bond has a maturity value of $1,000, an annual coupon of 12.0%, and 15 years left to maturity. The bonds can be called at any time with a premium of $50 per bond. If the bonds are called, the company must pay ...
October 20, 2011

physics
In a large hotel, a fast elevator takes you from the ground floor to the 21st floor. The elevator takes 17 s for this trip: 5 s at constant acceleration, 7 s at constant velocity, and 5 s at constant deceleration. Each floor in the hotel has a height of 2.5 m. Calculate the ...
September 26, 2011

Math
390
September 22, 2011

Math
Show how the Commutative Property of Addition works using the numbers 2, 3, and 5.
September 20, 2011

Math
Minnie has 6 country CDs and 5 rock CDs. Amanda has 5 rock CDs and 6 country CDs. Who has more CDs? Explain.
September 20, 2011

mkt 421
Marketing strategy planners should recognize that
August 14, 2011

mkt 421
Dell, Inc. wants to offer customers televisions in addition to computers. This is a change in their _____________________
August 14, 2011

mkt 421
For Tesla, a new firm that makes an electric sports car, estimating how many competitors will make electric vehicles and what kinds they will make, is:
August 14, 2011

equilibrium constant (Kp)
What is the equilibrium constant "Kp" at 200 C for the reaction below: P4(s) + 6 Cl2(g) --><-- 4 PCL3(l) Given the following at 200 C P4(s)+ 10 Cl2(g) --><-- 4 PCl5(s) Kc=8.12 PCl3(l)+ Cl2(g) --><-- PCl5(s) Kc=0.771 Answer: 6.7*[10^(-9)] not sure ...
July 20, 2011

Statistics
foofy computes the correlation between an individual's physical strength and his or her college grade poing average. Using a computer, the correlation for a sample of 2000 people is r(1998)=+.08, p=<.0001. she claims this is a useful tool for predicting which college ...
July 10, 2011

Chemistry
The following standard free energies are given for 25 degrees celcius. 1) N2(g) + 3H2(g)-> 2NH3(g) delta g = -33.0 kJ 2) 4NH3(g) + 5O2(g)-> 4NO(g) + 6H20() delta g = -1010.5 kJ 3) N2(g) + o2(g)-> 2NO(g) delta g = 173.1kJ 4) N2(g) + 2O2(g) -> 2NO2(g) delta g = 102.6...
July 6, 2011

statistics
Heights of fences are normally distributed with a mean of 52 inches and a standard deviation of 4 inches. Find the probability that one randomly selected fence is under 54 inches.
July 5, 2011

us history
((AN ERA OF LIMITS 1969-1980)) How were the relations between the United States and the Soviet Union different during this era? How were the relations the same?
June 22, 2011

us history
what nonmilitary measures did president kennedy take to counter Soviet influence and to spead democracy around the world? (clashes in the cold war)
June 20, 2011

us history
Yes i do mean we should NOT have been... && sorry i will proofread my posts.
June 18, 2011

us history
No wait i meant to put "helped" i wrote the question wrong! sorry HOW DID THE ANTI-WAR PROTEST HELP THE UNITED STATES DURING THE VIETNAM WAR? && one thing i know is that the United States started to believe that we should have been fighting in the first place.
June 18, 2011

us history
why did the anti-war protest hurt the united states during the Vietnam war?
June 18, 2011

precal
Given an initial value of 17 g, which is halving once each 32 hours, an exponential function in term of hour t which models this situation is ...?
June 12, 2011

Chemistry
Alright thanks so much.
June 7, 2011

Chemistry
How many mL of concentrated HCl(aq) (36% HCL by mass, d=1.18g/mL_ are required to produce 12.5 L of a solution with ph = 2.10? First I started with finding out the concentration of [H30+] and for that I got 7.94 x 10^-3 but I don't know how to continue.
June 7, 2011

Chemistry
Thanks so much. I did that and I used 751 for P, .205L for V, 0.08206 for R and 296 K for T and I got 6.34 moles. When I substituted that into the formula for M = moles/L I got 30.9 but the actual answer that is written in my textbook is 1.96 x 10^-3 M.
June 7, 2011

Chemistry
What is [H30+] in a solution obtained by dissolving 205mL HCl(g), measured at 23 C and 751mmHg, in 4.25L of aqueous solution?
June 7, 2011

math
You receive an invoice for $565.00 with terms 3/10, net 30. If you pay it immediately, how much will you pay? A. $548.05 B. $551.25 C. $558.05 D. $559.95
June 3, 2011

Chemistry
Okay I think I figured out how to do it all. Thanks for explaining.
May 28, 2011

Chemistry
No I wasn't, but can I just use the pressure formula of P() = nRT/V and then just add all of them together?
May 28, 2011

Chemistry
Sorry my ICE table came out wrong. It is actually suppose to be 2SO3 <-> 2SO + 02 I 0 .100 .100 C 0 .1- 0.0916 .1-.0458 E 0.0916 .0084 .0542
May 28, 2011

Chemistry
0.100 mol of SO2 and 0.100 mol of O2 are introduced in a flask of 1.52 L. When in equilibrium, 203 is found to be 0.0916 mol. Determine kp. 2S03(g) <-> 2SO(g) + O2(g) In order to solve this question 1st I made an ICE table and I got the values 2SO3 <-> 2SO + 02 I ....
May 28, 2011

math
How many real number solutions exist for 2x2 8x 8 = 0?
May 28, 2011

Chemistry
Thanks so much for your help.
May 28, 2011

Chemistry
Hi. Thanks for your help. So this is how I solved the equation. 2NO2(g) <-> 2NO(g) + O2(g) Since the 2NO2 is reversed from the 1st equation, I got (1/7.5x10^2) and then since the 2NO(g) and the O2(g) are doubled from the 1st equation I got (7.5x10^2)^2 for 2NO(g) and the...
May 28, 2011

Chemistry
Given the equation NO(g) + 1/2)O^2(g) <-> NO(g) at 457 Kelvin with a K = 7.5 x 10^2 Find the K value for the equation 2NO^2(g) <-> 2NO(g) + O(g)
May 28, 2011

Chemistry
Oh okay, thank you so much for your whole explanation. I finally understand the whole concept behind it and what we are suppose to do. Thanks so much again :)
May 28, 2011

Chemistry
Yeah I did all the previous things to find Kc and I got kc = 0.012. But you know how for to get the other kc you said I would have to do 1/sqrt Kc, I know that I would do that because the product is H2S and I would do the inverse because it is reversed and I would sqrt because...
May 28, 2011

Chemistry
So instead of looking at each compound in the equation you would only look at the product side of it and compare it to the other equation and only either square,square root etc. that value?
May 28, 2011

Chemistry
Given the equation 2H^2S(g) <-> 2H^2(g) + S^2(g) With a Kp = 1.2x10^-2 at 1338 Kelvin Find the value of Kc for the reaction H^2(g) + 1/2S^2(g) <-> H^2S(g) at 1338 Kelvin
May 28, 2011

Chemistry
Ok this helps so much. Thanks a lot I appreciate it.
May 25, 2011

Chemistry
Ok thanks so much. So when I solve for X I got 4.48(0.086 - x) = x^2 0.385 - 4.48x - x^2 = 0 Now i'd substitute that into the quadratic formula? Or is there an easier way to solve for X?
May 25, 2011

Chemistry
Okay thanks so much.
May 25, 2011

Chemistry
When I am solving for X my formula comes out to be 4.84 = X^2/ (.186-X) Can I assume that x << .05 and eliminate it from the denominator and just solve for the equation 4.84 = X^2/.186?
May 25, 2011

Chemistry
HCONH2(g) <-> NH3(g) + CO2(g) Kc= 4.84 at 400 K2(g) If 0.186 mol of HCONH2(g) dissciates in 2.16L at 400K, what will be the total pressure at equilibrium?
May 25, 2011

Chemistry
OK thanks so much, I appreciate it.
May 25, 2011

Chemistry
When I converted everything I got 1.2x10^3 = (0.02 + x) / (0.12 - x)(x) = (0.02 + x) / (0.12x - x^2) 1.2x10^3(0.12x - x^2) = 0.02 + x 144x - 1.2x10^3x^2 = 0.02 + x Then I brought x to the other side and I got 145x - 1.2x10^3x^2 = 0.02 Then I get confused with the x's and ...
May 25, 2011

Chemistry
Starting with 0.3500mol Co(g) and 0.05500mol COCL2(g) in a 3.050 L flask at 668K, how many moles of Cl2 are present at equilibrium? Co(g) = Cl2(g) <-> COCL2(g) Kc = 1.2x10^3
May 25, 2011

Chemistry
Thank you so much. I got 9.7 x 10^-16. The answer is correct. I was just confused because why did we only substitute the k values for 2 compounds in the equation rather then all 4?
May 25, 2011

Chemistry
Determine Kc for the following reaction: 1/2N2(g) + 1/2O2(g)+ 1/2Br(g) <-> NOBr(g) from the following information (at 298K) 2No(g) <-> N2(g) + O2(g) Kc = 2.1x10^30 NO(g) + 1/2Br2(g) <-> NOBr(g) Kc = 1.4
May 25, 2011

math
how do you use the numbers 4, 5, 9, 7, and 21 to get the number 23 (using it in a number sentence) i cannot get it and its driving me crazy! please help
May 17, 2011

Chemistry
The Hydrolysis Reactions - Write net-ionic equations for the reaction of each salt with water below. If there is no reaction, write N.R. 1. NH4C2H3O2 2. NH4Cl 3. NaCl 4. Na2CO3 5. NaC2H3O2 6. NaHSO4 7. FeCl3 8. NaH2PO4 9. NaHCO3
April 30, 2011

math
yeah in some cases if you really truley need it,like maybe if your dealing with decimals
April 28, 2011

algebra
explain why a solution of a word problem should be checked using the original wording of the problem and not the equation written from the wording
April 12, 2011

math
8x+16÷x^(2)-1 . x+1÷4x+8
March 30, 2011

physics
It takes 15 seconds for a wave to pass a buoy 25 meters from shore. If its wavelength is 30 meters, what is its speed.
March 30, 2011

Chemistry
Titration of an Unknown Acid... What effect on the molar mass of the unknown acid would each of the following have... Would it make the calculated molar mass high, low, or would it have no effect? 1. Adding 5 drops of phenolphthalein instead of 1 drop... Answer: No effect. 2. ...
March 26, 2011

Chemistry
Would it be better to use an unknown acid sample of a size that should require 10.00 milliliters or one that would require 15.00 milliliters of titrant? Explain. I have been thinking about this question... And I don't believe it matters what measurement of milliliters is ...
March 26, 2011

Chemistry
Thank you.
March 26, 2011

Chemistry
Why is it important to swirl the NaOH solution each time before using it during a titration?
March 26, 2011

physics
Two electrostatic point charges of +30 ìC and +25 ìC exert a repulsive force of 200 N on each other. What is the distance between the two charges?
March 25, 2011

Math
A right square pyramid’s base has edges measuring 20 feet each. If the pyramid’s height is 27 feet, what is its volume, in cubic feet?* *Could you include an explanation as well?
March 15, 2011

Chemistry
The freezing point of a cyclohexane sample is 6.20*C. A soltuion is prepared by dissolving 0.4660g of an unknown solute in 36.0g cyclohexane. The freezing point of the solution if 4.11*C. Calculate the molar mass of the unknown solute. Kf for cyclohexane is 20.0*Ckg/mole.
March 14, 2011

earth science
how does the apparent diameter of the sun from earth affect the orbital velocity?
March 14, 2011

physics
how much should a ramp rise over 10 meters of run for an angle of 12 degrees
March 10, 2011

Calculus
D) 54 One vertex is x,y and the other is -x,y y= 27 - x^2 A= 1/2 BxH B = x - -x = 2x H = 27 - x^2 A = 1/2 * 2x * (27 - x^2) Take the derivative, find when the derivative is = 0 then plug that back in to get dimensions and solve for area.
March 8, 2011

Chemistry
What are 3 possible reasons why a percentage recovery might be low? And what are 3 possible reasons why a percentage recovery might be well over 100%?
March 6, 2011

Chemistry
Iron is obtained from iron ore according to the following reaction: Fe2O3+CO---> Fe+CO2 (unbalanced). a. Assuming the blast furnace is 90.0% efficient in recovering the iron, what is the actual mass of iron obtainable from a ton of ore? b. What is theoretical yield of iron ...
March 6, 2011

Chemistry
How many milliliters of 3.0 M NaOH are required to react with 0.50g of Cu2+ to form Cu(OH)2?
March 6, 2011

Chemistry
How many milliliters of 3.0 M NaOH are required to react with 4.0mL of 16.0 M HNO3? ---> Not sure if I am solving correctly but I keep getting 21mL.
March 6, 2011

French - Help :(
Hi all. I'm trying to write a paragraph in french. These are my instructions: Décrivez vos activités habituelles pendant les vacances dernières en utilisant au moins sex verbes réfléchis à l'imparfait. This is what I want to ...
March 1, 2011

geometry
The width will be 6 in.
February 17, 2011

Math
4/13 is cause 4*3 is 12 so thats the close you gonna get so the answer is 31
February 14, 2011

Chemistry
A 0.188g sample of unknown metal, X (s), produced 71.4 ml of hydrogen gas when reacted with HCL according to the equation: X(s)+2HCL(aq)--->XCl2(aq)+H2(g) The gas was collected over water at 23 degrees Celsius. The levels of water inside and outside the gas collecting tube ...
February 10, 2011

Chemistry
A 0.0677g sample of magnesium metal reacted with excess hydrochloric acid to produce 69.9 ml of hydrogen gas. The gas was collected over water at 21.0 degrees Celsius. The levels of water inside and outside the gas collecting tube is identical. The water vapor pressure at 21.0...
February 10, 2011

Chemistry
A sample of oxygen gas is collected by displacing water from an inverted bottle as shown in the diagram below. The volume of O2(g) collected is 400.0ml at 25 degree Celsius. The atmospheric pressure is 680 torr and the vapor pressure of water at 25 degree Celsius is 23.8 torr...
February 3, 2011

Chemistry
CaO(s) reacts with SO2(g) according to the following equations: CaO9(s)+So2(g)--> CaSO3(g). A 8.85g mixture containing CaO(s) is placed in a 3.00-L container. The container is filled with SO2(g) to a pressure of 749 torr, at 20.0 degree Celsius. After the reaction has gone ...
February 3, 2011

Chemistry
Consider the flasks diagrammed below. What is the total pressure in torr after the stopcock between the two flasks is opened? He(g)---> V=1.25L and P=0.300atm and Ar(g)---> V=2.50L and P=233 torr.
February 3, 2011

Chemistry
A steel cylinder contains 98.0 moles of oxygen gas at temperature of 38 degree Celsius and a pressure of 740 torr. After some of the oxygen gas has been used, the pressure is reduced to 332 torr at a temperature of 24 degree Celsius. What mass of oxygen gas is removed from the...
February 3, 2011

Chemistry
A compound contains only hydrogen and nitrogen and is 12.6% hydrogen by mass. A gaseous sample of the compound has density of 0.925g/L at 690 torr and 110 degree Celsius. What is the molecular formula of the compound?
February 3, 2011

Math
The graphs of y= x^2 - 8x - 35 and y= -2(x^2) + 16x +3 intersect in two points. What is the sum of the x-coordinates of the two points of intersection?
February 2, 2011

Math
How many non-congruent triangles with only integer side legnths have a perimeter of 15 units?
February 2, 2011

Math
There is a 4 x 4 square grid. Two unit squares are chosen from the 16 unit squares possible. What is the probability that they do NOT have a vertex in common? Express your answer as a common fraction.
February 2, 2011

Math
There is a 4 x 4 square grid. Two unit squares are chosen from the 16 unit squares possible. What is the probability that they do NOT have a vertex in common? Express your answer as a common fraction.
February 2, 2011

algebra
4.42 hrs. 1/7 +1/12 = 19/84 84/19= 4.42...
February 2, 2011

Math
When x^2-5x+3c is divided by x-3 the remainder is -12. What is the value of c?
February 2, 2011

Math
How many unit cubes would it take to construct the complete exterior of a hollow cube with edges of 4 units and faces 1 unit thick?
February 2, 2011

Chemistry
Concentrated sulfuric acid is 18.4 molar and has a density of 1.84 grams per milliliter. After dilution with water to 5.20 molar the solution has a density of 1.38 grams per milliliter. This concentration of H2SO4 is often used in lead storage batteries(like a car battery). 1....
January 13, 2011

Chemistry
Thank you.
January 11, 2011

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