Thursday

April 24, 2014

April 24, 2014

Total # Posts: 49

**chemistry**

A ground water source contains 2.5 mg of F- ion per liter. a) what is the concentration of F- ions in moles per liter? b) will CaF2 (Ksp = 2E-10) precipitate when the concentration of Ca2+ = 5.0E-3M?

**chemistry**

how many liters of oxygen are necessary for the combustion of 340 g of ethanol (c2h5OH) assuming the raction occurs at STP? no idea how to work this out

**chemistry**

what is the boiling point of a solution of .01 mole of glucose(C6H22o6) in 200 g of water. kb=0.512C/m.

**Chemistry**

I need to calculate the redox potential for the following: 1/2 O2 + 2H+ + 2e- <-> H2O I'm using the formula E = E'_0 + RT\nF ln ([electron acceptor]/[electron donor]) The electron acceptor is H+, so I can use the concentration of that which is indicated by the pH...

**Chemistry**

The biomass formula for a yeast is CH1.66 00.269 N0.194. The formula accounts for 92% of dry mass; the other 8% is inorganic material (ash). When grown on C6H14, the yield on biomass is 1.4 gcell/gsubstrate. What is the respiratory quotient (mole CO2 produce/mole O2 consumed)?...

**physics**

tom the cat is chasing jerry the mouse across the table surface at 1.5 m high, jerry steps out of the way and tom slides off the table at 5m/s. Where will tom hit the floof and what are the velocity components just before impact

**calculus**

find the definite integral that is equivalent to lim n->infinity of sum over i=(1,n) n/(n^2+i^2) since definite integral of f(x) dx over (a,b) = lim n->infinity sum over i=(1,n) f(a + (b-a)i/n) * (b-a)/n then: f(a + (b-a)i/n) * (b-a)/n = n/(n^2+i^2) rearrange to: so f(a ...

**Chemistry**

Draw Lewis Structure for BrO3^- The textbook answer involves a central Br atom with one lone electron pair and five shared pairs (two double bonds and one single bonds). This gives Br twelve electrons rather than the typical eight. I understand that some atoms like Br have exp...

**calculus**

nevermind, I got it. The trick was using trigonometric reduction formulas.

**calculus**

Integrate sqrt(x^2 + 1) dx over [0,2*pi] I can substitute u=arctan x to get: Integrate (sec u)^3 du over [0,arctan(2*pi)] From there, I'm stuck. (thanks Count Iblis for your last help)

**Calculus**

"Leave the answer as a definite integral, but indicate how it could by evaluated by using the fundamental theorem of calculus." I solved the problem to a definite integral. Proceeding via the fundamental theorem, would involve finding the indefinite integral (or anti...

**Chemistry**

For the reversible, one-step reaction A + B ARROW C + D, the forward rate constant is 35.9 1/(M·h) and the rate constant for the reverse reaction is 25.4 1/(M·h). The activation energy was found to be 33.0 kJ/mol for the forward reaction and 45.6 kJ/mol for the r...

**chemistry**

i got the answer!

**chemistry**

The rate constant of the reaction between CO2 and OH - in aqueous solution to give the HCO3- ion is 1.5 1010 1/(M·s) at 25°C. Determine the rate constant at blood temperature (37°C), given that the activation energy for the reaction is 38 kJ/mol. units 1/(M&midd...

**Math**

Posted a question on the 2/12/12 at 3:48PM and was never given an answer. Guess the math problem is too hard for anyone to solve. How do they expect me to answer it if no one else can? Thanks for your time. Parker.

**calculus**

f''(x) = 24x - 18 f'(x) = 12x^2 - 18x + C Since f'(1) = -6, then -6 = 12(1)^2 - 18(1) + C -6 = 12 - 18 + C -6 = -6 + C C = 0 So f'(x) = 12x^2 - 18x f(x) = 4x^3 - 9x^2 + C Since f(2) = 0, then 0 = 4(2)^3 - 9(2)^2 + C 0 = 4(8) - 9(4) + C 0 = 32 - 36 + C 0 = -...

**Math**

Hayley has 16 square boxes to make an array of rectangular shapes on a grid. Harry says if she uses 19 square boxes she will get more arrays. Do you aree or disagree with Harrys' claim? Explain your answer using prime and composite numbers. Use the drawings of the rectangl...

**trig**

A water-park slide covers 100 feet of horizontal space and is 36 feet high. A new replacement slide will create an angle with the water surface that measures twice that of the original slide. The new slide will use the same horizontal space as the old slide. What is the height...

**trig**

Two pilots take off from the same airport. Mason heads due south. Nancy heads 23º west of south. After 400 land miles, how far is Nancy from Mason’s route? Round your answer to the nearest tenth of a mile. (Enter only the number.)(If someone had helped me with the on...

**trig**

A hill rises from the horizontal at 15º. The road leading straight up the hill is 800 meters long. How much higher is the top of the hill than the base of the hill? Round to the nearest meter. (Enter only the number.)

**trig**

Alan is using the equation mg sin A = umg cos A to determine the coefficient of friction, u, between a flat rock and a metal ramp. Find u to the nearest hundredth, if the rock begins to slide at 19º.

**Stats Question**

People were polled on how many books they read the previous year. How many subjects are needed to estimate the number of books read the previous year within one book with 99% confidence? Initial survey results indicate that standard deviation= 15.9 books.

**trig**

Solve for ¥è in the equation tan ¥è = 2.42 when 180¨¬ < ¥è < 360¨¬. Round your answer to the nearest tenth of a degree. (Enter only the number.)

**trig**

Solve sin ¥è = -0.204 for 90¨¬ < ¥è < 270¨¬. Give your answer to the nearest tenth of a degree.

**trig**

Triangle XYZ has vertexes at X(-4, 5), Y(-3, 5), and Z(-3, 4). Find the measure of angle Y to the nearest degree.

**trig**

A cashier is unsure whether a group of customers ordered and ate a large or a medium pizza. Medium pizzas have a diameter of 12 inches and large pizzas have a diameter of 16 inches. All that remains is one crust that has an arc length of 4.25 inches. All pizzas are divided int...

**trig**

P(2, 9) is a point on the terminal side of è in standard position. What is the exact value of tan è?

**spelling**

3 adjective words left to unscramble 1)B+U+T+us 2)c+(what Mrs. Sprat couldnt eat)+a birds home 3)D+pain in the neck

**spelling**

3 adjective words left to unscramble B+U+T+us

**Math**

If tanA = the square root of 11, find tan2A

**physics 11 grade**

A hiker shouts toward a vertical cliff 789.5m away. The echo is heard 2.1s later. The wavelength of the sound is 12.3 m. What is the speed of the shout? What is the frequency? What is the period of the wave?

**High School Physics**

At rest, a swing is 23.7m above the ground. When Sam performs he always pulls the swing as high as he can to 45.5m. While performing Sam 88.1 kg, is moving pretty fast at his lowest point 23.7m above the ground. What is his kinetic energy at that point? (j)

**surveying**

on a lake without any waves, how far from the shore is a sailboat when the top of 10 m mast disappears from view of a person whose eye height is one m above the water's edge

**math**

12-(-5)+(-11)

**Science**

Two bumper cars collide and then move away from each other. How do the forces the bumper cars exert on each other compare?

**Calculus**

Water is being pumped into an inverted conical tank at a constant rate. The tank has height 12 meters and the diameter at the top is 4 meters. If the water level is rising at a rate of 26 centimeters per minute when the height of the water is 1 meters, find the rate at which w...

**calculus**

At noon, ship A is 10 nautical miles due west of ship B. Ship A is sailing west at 17 knots and ship B is sailing north at 20 knots. How fast (in knots) is the distance between the ships changing at 4 PM? (Note: 1 knot is a speed of 1 nautical mile per hour.)

**calculus**

It still says NOT CORRECT.

**calculus**

At noon, ship A is 10 nautical miles due west of ship B. Ship A is sailing west at 17 knots and ship B is sailing north at 20 knots. How fast (in knots) is the distance between the ships changing at 4 PM? (Note: 1 knot is a speed of 1 nautical mile per hour.)

**4th grade**

What is a region, continent, and hemisphere?

**Math (Find the Value)**

If 0 < (theta) and cos(theta)=0.5, then what is the value of cos(2theta)?

**physics**

Neither do I.

**physics**

tiny.cc[slash]cTtCg

**English Lit**

Describe an obstacle to working on teams. Explain how the team can overcome that obstacle.

**math**

the lions ate up all the prophets :D this was a riddle on my math hw

**social studies**

What were the mummy-shaped figures that worked in the afterlife's fields for the mummy called?

**Math**

Here's the direction I was given: Write an expression for the sequence in each table. 1 - 8 2 - 13 3 - 18 4 - 23 5 - 28 n - ___ Would I write n = 28+5 ?

**Algebra**

If you have these three origins: (0,0) (0,952) (863,0) How do you find the last point where the two lines intersect? Would really appreciate the help. Thanks. Parker, I'm not quite sure what the question asks. Three origins? Is this standard analytic geometry we're doi...

**Management Science**

1. Modeling is used to: a) Save time b) Save money c) Analyze to the fullest d) All of the above e) A and B, but not C

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