Friday
August 28, 2015

Posts by K


Total # Posts: 799

Chem
A 53.31-g sample of water at 88.8 degrees C is added to a sample of water at 23.9 degrees C in a constant- pressure calorimeter. If the final temperature of the combined water is 43.3 degrees C and the heat capacity of the calorimeter is 26.3 J/degrees C, calculate the mass of...
November 2, 2012

math
grant's change rack contained $8.80 in quarters, dimes, and nickels. There were two more than five times as many nickels as quarters and four less than twice as many dimes as quarters. How many of each kind of coin was there in the change rack? please help
October 22, 2012

math
The second of three numbers is 1 less than than the first. The third number is 5 less than the second. if the first number is twice as large as the third, find the three numbers. write an equation and find the numbers
October 10, 2012

math
the greater of two numbers is 1 more than twice the smaller. three times the greater exceeds 5 ties the smaller by 10. find the numbers and write the equation. please help me
October 10, 2012

math
The second of three numbers is 1 less than than the first. The third number is 5 less than the second. if the first number is twice as large as the third, find the three numbers. write an equation and find the numbers please help me
October 10, 2012

physics
two masses one on an inclined plane at 30 degrees the other suspended
September 26, 2012

college physics
Newton's second law states that for every action there is an equal and opposite reaction. Draw a force diagram. It is moving at a constant velocity. Your force diagram for an object moving at a constant velocity is the same as your force diagram for an object at rest, so ...
September 24, 2012

Chemistry
lh
September 23, 2012

Chem
Paper thickness varies. Typically, 100 sheets are about a cm thick. Atoms typically vary from 1 to 3 angstroms in radius. (An angstrom is 10-10 m.) Suppose a piece of paper is 0.0073 cm thick. How many atoms span the thickness if the radius of the atom is 1.94 angstroms?
September 12, 2012

geology
why do planets appear to move with respect to stars?
September 11, 2012

algebra
Perform the subtraction. (4x/x^2+2x-8)-(x/x^2-16)
September 9, 2012

math-algebra
Factor the polynomial 64x^3-27
September 9, 2012

geology
determine the Radiocargon age of the sample from its % Modern value. Fragment of Roman Gladiator leather harness 77% modern ___ radiocarbon age BP ____ correct radiocarboned age
September 4, 2012

geology
Below are descriptions of samples, with known ages expressed as either AD or BC (also called BCE). Convert these dates to BP dates (using 1950 as "the present.") 1. Wood from Egyptian coffin - from the Ptolemic period based on style. Date: 200 ± 150 years BCE
September 4, 2012

Physics
9
September 2, 2012

Physics
Good luck with your AGU entrance exam test this Saturday. :D
August 28, 2012

math
How many ounces of water could be held in a cylinder that has a radius of 2inches and a height of 7 inches if every cubic inch of volume cantains one-fourth ounce of water?
August 21, 2012

geography
1. All of the following are among the Pillars of Islam except. A. performing daily prayers. B. memorizing the Koran. C. giving to charity. D. making a Hajj. 2. What was the result of Iran's 1979 revolution? A. The Sunnis defeated the Shiites in their struggle for control ...
August 16, 2012

math
Give the component form of the resultant vector in the following. u = (10, 5) -3u = ?
July 21, 2012

chemistry
Thank you very much Dr. Bob for your help. I didn't post the original question, but was working on a similar problem. It probably would have taken me an hour to figure this out without your help. Thanks again!
July 7, 2012

Math help please
(This homework question was removed due to a copyright claim submitted by k12.com.)
May 21, 2012

Chemistry
Amino acid solution was made by taking 3.58 g of the dry amino acid and making it up to 1.00L in water. A 25.0 mL sample was taken and titrated with NaOH of concentration of 0.0493M, with the first equivalence point at 18.15 mL and the second equivalence point at 32.05 mL. ...
May 20, 2012

combine functions.. please help.
Given: f(x)=2x^2-x+1 g(x)=2 sin x h(x)=3^x Determine: a) f(g(x)) b) (h^-1 o f)(x) c) g(f(h(x)))) Please show steps, thank you very much.
May 17, 2012

World Civilizations
A Hindu society in Southeast Asia that resisted both Buddhism and Islam was
May 4, 2012

5th grade math
She either scored 196 or 327 points Explaination: Range is difference between greatest and smallest numbers. We know the answer of range that is 129. If we consider 325 as greatest number than we can subtract 129 from 325 and get smallest number - 196. If we consider 198 as ...
April 19, 2012

chemistry
The rate constant for this first-order reaction is 0.0570 s–1 at 400 °C. A-->Products After how many seconds will 14.0% of the reactant remain?
March 23, 2012

geom/trig
The base of a right rectanglar prism is 12 cm by 8 cm. The height is 5 cm. Find its surface area.
March 5, 2012

algebra 2
evaluate f(x) = x^-2/3 + x^-3 for each value of x. f(-8)
March 5, 2012

math
name two different numbers that are greater than .66 and less than .9
February 22, 2012

calculus
f(x)= 3x^7 +2x -9 If g(x)= f inverse of x and g(-4)= 1, what is g'(-4)? I know that f inverse is the same as 1/f'(x) but I'm not sure where to go from there.
February 21, 2012

math
Seven thousand raffle tickets are to be sold at $10 each to benefit a local community group. The prizes, the number of each prize to be given away, and the dollar value of winnings for each prize are as follows: Prize Number to Be Given Away Dollar Value Automobile 2 $21,730 ...
February 11, 2012

math
Suppose that an automobile parts wholesaler claims that .5 percent of the car batteries in a shipment are defective. A random sample of 200 batteries is taken, and four are found to be defective. (a) Use the Poisson approximation to find the probability that four or more car ...
February 11, 2012

math
A telephone company's goal is to have no more than 4 monthly line failures on any 100 miles of line. The company currently experiences an average of 5 monthly line failures per 50 miles of line. Let x denote the number of monthly line failures per 100 miles of line. ...
February 11, 2012

math
A telephone company's goal is to have no more than 4 monthly line failures on any 100 miles of line. The company currently experiences an average of 5 monthly line failures per 50 miles of line. Let x denote the number of monthly line failures per 100 miles of line. ...
February 11, 2012

calculus
Find the limit. lim h → 0 square root (49 + h) − 7 / h Note: Only 49 +h are under square root.
February 2, 2012

chemistry
A patient has 0.050 L of blood drawn and this volume of blood has a mass of 55.0 g. What is the density of the blood? Answer with the correct number of sig figs
January 31, 2012

chemistry
(3.84 x 103 x 0.764) + 1.59 answer with the correct sig figs
January 31, 2012

Chemistry - Naming Compounds
Name the following compound. Ba3Pb2 I don't really understand since both the elements are metals and usually these bonds occur with a metal and nonmetal or two nonmetals.
January 30, 2012

chemistry
Chloroquine is used to treat malaria. Studies have shown that an effective dose for children is 3.5 mg per kilogram (3.5 mg/kg) of body weight, every 6 hours. If a child weighs 21 kg, how many milligrams of this drug should be given in a 66 hour period?
January 30, 2012

chemistry
Which of the following is a situation where an object’s potential energy varies as a result of changes due to its chemical composition? The melting of ice. The burning of wood. A ball rolling down a hill. A parachute slowing a skydiver's fall.
January 29, 2012

chemistry
Which of the following is an example of a chemical change (change in chemical composition) that involves starting with a liquid and ending up with a gas? Burning gasoline (combustion). Boiling acetone. A pond evaporating. Condensation of steam.
January 29, 2012

Calculus
what is the inverse function of f(x)=-[sqrt(25-x^2]
January 24, 2012

calculus (limits)
Use limits to explain why f(x)= (7-3X)/(X+9) has a vertical asymptote.
January 21, 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

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

7th grade Science
dmf
September 24, 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

physics
the
September 13, 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

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