Saturday

January 31, 2015

January 31, 2015

Total # Posts: 149

**Chemistry**

When a chemist burns ammonia according to the reaction below she finds that the reaction releases heat. (It is exothermic.) 4NH3(g) + 3O2(g) 2N2(g) + 6H2O(g) The enthalpy of the reaction DH = -1267 kJ. What is the enthalpy change (in kJ) when 7 grams of ammonia are burned?
*January 12, 2015*

**Chemistry**

Calculate the total heat (in Joules) needed to convert 1.602 x 101 grams of ice at -1.383oC to liquid water at 8.554 x 101oC. Melting point at 1 atm 0.0oC Cwater(s) = 2.09 J/goC Cwater(l) = 4.18 J/goC delta Hofus = 6.02 kJ/mol
*January 12, 2015*

**physics**

A plane cruising along at 268 m/s, in straight level flight wants to drops a bomb. He is at a height of 1000m. At what distance should the pilot release the bomb in order to hit his target?
*November 9, 2014*

**Physics **

(a) How high a hill can a car coast up (engine disengaged) if friction is negligible and its initial speed is 96.0 km/h? (b) If, in actuality, a 750 kg car with an initial speed of 96.0 km/h is observed to coast up a hill to a height 18.0 m above its starting point, how much ...
*October 17, 2014*

**8th grade math**

At 2pm the temperature is 22 degrees, by 4am it is negative 7 degrees. We think the answer in the change of temperature is 29 degrees am I right?
*September 30, 2014*

**8th grade Math**

Ok, I came up with 29
*September 30, 2014*

**8th grade Math**

At 2pm the temperature is 22 degrees, by 4am it is negative 7 degrees. We think the answer in the change of temperature is 22 degrees am I right?
*September 30, 2014*

**Algebra**

6-(-5r)=5r-3
*September 19, 2014*

**math**

what is the exponential form of 1000 * 1000
*August 25, 2014*

**Algebra**

Can anyone please show me how 3^n/6^(2n+1) becomes 1/2^n(6^(n+1))= 1/6)/12^n when you divide top and bottom by 3^n? Thank you and have a great day!
*July 30, 2014*

**statistics**

To find out what people think, the Gallup Poll selected a random sample of 520 women and 506 men. The pollsters showed them a list of personal attributes and asked them to indicate whether each attribute was “generally more true of men or of women”. When asked about ...
*June 27, 2014*

**College Chemistry**

1 L of N_2_ gas, having a pressure of 2.5 atm, is added 1 L of Ar gas, having a pressure of 3.7 atm, in a sealed, rigid flask. What is the final pressure in the flask?
*May 8, 2014*

**math**

How do you solve sqrt(1-(9/x^2))? I know the answer is sqrt x^2 -9/x but I'm not sure how to get the answer on my own. If you could show steps on how to get the answer that would help me a lot!
*February 11, 2014*

**math**

how do I figure the circumference of race track that takes 3 lap to make a mile?
*December 17, 2013*

**math**

Jeff Iron $250 on his $5000 certificate of deposit last year. what simple interest rate did the bank pay him?
*July 14, 2013*

**chemistry**

A 7.56-g sample of gas is in a balloon that has a volume of 10.5 L. Under an external pressure of 1.05 atm, the balloon expands to a volume of 15.00 L. Then the gas is heated from 0.00 degree C to 25 C. If the specific heat of the gas is 0.909 J/g*C, what are work, heat, and ...
*July 13, 2013*

**Chemistry**

ph=10.3
*July 13, 2013*

**Complex Physics Problem**

A ladder can fall for two reasons. If it is set too steep and climber gets their mass to the left of the ladder's base, the ladder likely will fall over backwards. If the ladder is set at too shallow of an angle the required force of friction between the ladder and the ...
*June 29, 2013*

**College Level Physics**

A horse pulls a cart with a force of 145 newtons at an angle of 30 degrees above the horizontal and moves along at a speed of 2.5 m/s. How much work to the nearest kJ does the force do in 6 minutes?
*June 9, 2013*

**Physics 1 College Level**

A planet/moon has a mass of 77.89 × 1023 kg and a radius of 7.9 × 106 meters. What is g on the surface to the nearest hundredth of a m/s2? Once again, not really sure where to go with this. Out of the 10 problems I've only had trouble with this and one other.
*June 1, 2013*

**Physics 1 College Level**

Spaceship is 2.5 x 10^7 kg! Asteroid is 3.5 x 10^18 kg. Thanks! I'll try and figure it out and compare answers if you respond back!
*June 1, 2013*

**Physics 1 College Level**

If D = 3204 meters and d = 1247 meters in the figure, what is the magnitude of the force on the space ship to the nearest MN? Consider all three to be point masses. I'm not even sure to begin with this question. Any help will be much appreciated!
*June 1, 2013*

**Math**

A state lottery requires you to choose 4 cards from an ordinary deck: I heart, 1 club, 1 diamond, and 1 spade in that order from the 13 cards in each suit. If all four choices are selected by the lottery, yo win $5,000. It costs $1 to play. Find the expected payback.
*April 2, 2013*

**university**

n^2+n+1 = (n+1)^2 - n (n+1)^2 and n will always have the different parity, so the difference between them is always odd.
*March 27, 2013*

**probability**

6 male students and 3 female students sit around a round table. What is the probability that no 2 female students sit beside each other?
*March 25, 2013*

**MATH**

110% OF $8.50
*March 15, 2013*

**Calculus**

The area bounded by the curve y = 2x^2-x^3 and line y=0 is rotated around the y-axis. The volume of the resulting structure can be expressed as V = a(pi)/b, where a and b are coprime positive integers. What is the value of a + b?
*March 15, 2013*

**GEOmetry**

4455551 = 4x4x5x5x5x5x1=10000 the proof is not valid.
*March 4, 2013*

**Pre-calculus; urgent ! Please help !**

I'm taking this same class you should add me on Facebook lol Symone kaepernick
*February 26, 2013*

**math**

If Mark invests $8000 at 6% simple interest rate, how much money must he invest at an 8% simple interest rate in order for the interest on each investment to be $500. Assume that the amount of time for both investments is the same.
*January 23, 2013*

**Math**

The velocity of a body A is given by v(t) = 2t^i + t 3^j. The body starts from rest at time t = 0 and position s(0) = 2^i 10^j. At what time, t, does the body cross the X axis? What is the average velocity of the body for the time interval, t = 0 and the time that it crosses ...
*January 22, 2013*

**Dynamics**

The acceleration of a particle moving along a straight line is inversely proportional to its speed with the constant of porpotionality being k. The body starts from the position s = x0 ^i with initial speed v0. Determine the velocity of the particle as a function of time t. ...
*January 22, 2013*

**Algebra2**

Find and simplify a) f(a), b) f(a + h) and c) F(a+h) - f(a) / h ; 1. f(x) = x^2 + 5x -10
*November 29, 2012*

**Spelling 4th grade**

Fly
*November 26, 2012*

**Calculus**

Can I simplify (x^.75)((200-3x)^.5)?
*November 13, 2012*

**calculus**

1/4x+(6)3/4
*November 9, 2012*

**Physics**

A bullet with a mass m=12.5 g and speed v=85.4 m/s is fired into a wooden block with M=113 g which is initially at rest on a horizontal surface. The bullet is embedded into the block. The block-bullet combination slides across the surface for a distance d before stopping due ...
*October 25, 2012*

**Successive approximations**

Find all root of ln(4-x^2)=x correct to 8 decimal places. List all successive approximations.
*October 20, 2012*

**Calculus**

Graph the following function. Find and state the domain, intercepts, asymptotes, intervals of increase and decrease, local extrema, concavity, and inflections points. F(x)=(x+1)/(square root(x^2+1)) I got so far... Domain: (-infinity, infinity) Intercepts: (0,1)and(-1,0) ...
*October 20, 2012*

**Physics**

A baseball is hit at ground level. The ball reaches its maximum height above ground level 3.2 s after being hit. Then 2.7 s after reaching its maximum height, the ball barely clears a fence that is 81.0 m from where it was hit. Assume the ground is level. (a) What maximum ...
*October 9, 2012*

**Physics**

A baseball is hit at ground level. The ball reaches its maximum height above ground level 3.2 s after being hit. Then 2.7 s after reaching its maximum height, the ball barely clears a fence that is 81.0 m from where it was hit. Assume the ground is level. (a) What maximum ...
*October 9, 2012*

**Physics**

A train at a constant 44.0 km/h moves east for 42 min, then in a direction 45.0° east of due north for 17.0 min, and then west for 51.0 min. What are the (a) magnitude (in km/h) and (b) angle (relative to north, with east of north positive and west of north negative) of ...
*October 9, 2012*

**Physics**

A batter hits a pitched ball when the center of the ball is 1.35 m above the ground.The ball leaves the bat at an angle of 45° with the ground. With that launch, the ball should have a horizontal range (returning to the launch level) of 106 m. (a) Does the ball clear a 8....
*October 9, 2012*

**Physics**

A baseball is hit at ground level. The ball reaches its maximum height above ground level 3.2 s after being hit. Then 2.7 s after reaching its maximum height, the ball barely clears a fence that is 81.0 m from where it was hit. Assume the ground is level. (a) What maximum ...
*October 9, 2012*

**practical english**

Which of the following sentences contains an italicized word that's used as a predicate adjective? A. Jerry looks ILL today. B. Jerry looks INTO the microscope. C. Jerry looks disdainfully at the pile of laundry D. Jerry looks at the map. Is it c?
*September 25, 2012*

**health**

is it d
*September 20, 2012*

**Physics**

How do I find Vector Resolution F = 0.300 g N, theta = 60 degrees. Do I take tan inverse (.3 sin 60/.3 cos 60)?
*September 17, 2012*

**College Finite**

Assume that the student has a cup with 13 writing implements: 7 pencils, 4 ball point pens, and 2 felt-tip pens. In how many ways can the selection be made if no more than one ball point pen is selected?
*September 6, 2012*

**chemistry**

What is the density of a substance that weighs 500g and fills a container that is 1/2 liter in size?
*September 6, 2012*

**college algebra **

an executive invests $29,000 some at 7% and some at 6% annual interest. if he receives an annual return of $1870, how much is invested at each rate?
*August 26, 2012*

**College Physics**

A person jumps from a window 34 meters high and is caught in a firefighter's net which stretches 0.6 meter. To the nearest m/s^2, what is the magnitude of the person's acceleration in the net?
*August 26, 2012*

**Geometry **

Company "A" sells soil at 11 cents per cubic foot. While company "B" sells it at 3 dollars per cubic yard. You need to have 20 cubic yards of soil planted. What is the better company to go with? and how much will you save?
*July 10, 2012*

**American History**

is it D
*June 6, 2012*

**Enlish III**

The graduation cermoney lasted only two hours. What part of the sentence is lasted only two hours? A) verb B) compound verb C) complete Predicate D) Complete subject
*May 29, 2012*

**chemistry**

A gas has a volume of 50.0 cm3 at a temperature of -73°C. What volume would the gas occupy at a temperature of -123°C if the pressure stays constant?
*April 23, 2012*

**Calculus**

a.) Given that f(3)=5 and f'(x)=x/((x^3)+3), find the linear approximation of f(x) at x=3. b.)If the linear approximation is used to estimate the value of f(2.9), will it be an overestimation or underestimation? Show justification
*March 16, 2012*

**Math**

a.) Given that f(3)=5 and f'(x)=x/((x^3)+3), find the linear approximation of f(x) at x=3. b.)If the linear approximation is used to estimate the value of f(2.9), will it be an overestimation or underestimation? Show justification.
*March 16, 2012*

**Math**

The stopping distance d of a car in feet is related to the speed in mph by the equation d(s)=.02s^2+1.1s Calculate the speed when your stopping distance is: 1.) 51ft 2.) 315.12ft
*February 25, 2012*

**Math**

A math teacher wrote x^2+bx+c=0 on the board and asked students to find the two real roots. Alice miscopied one of the coefficients and found that 1 and 4 were the roots. Andy miscopied a different coefficient and found that -2 and 3 were the roots. Determine the roots to the ...
*February 25, 2012*

**Math**

Find the roots of the given equation by completing the square: ax^2+bx+c=0
*February 25, 2012*

**algebra**

The time it takes you to go 12 miles upstream is 5/4 the time it takes you to go 14 miles downstream. If the current is 3mph, how fast do you go in still water.
*February 25, 2012*

**science**

need a example of the ecosystem cliche
*January 11, 2012*

**chemistry**

Lewis dot of free radical cf2cl and hoco
*December 5, 2011*

**chemistry**

Lewis dot of free radical cf2cl and hoco
*December 5, 2011*

**chemistry**

The average out door concentration of carbon monoxide ,co at 15 c and 1 atm of pressure is about 900 micrograms per cm^3 . What is this concentration expressed : on ppm scale ? And on the molecules /cm^3scale?
*December 5, 2011*

**chemistry**

Ln(100)/1)=(0.693/t^1/2)(t). ??? Don't get it
*December 5, 2011*

**chemistry**

Sorry don't understand it is 99 percent
*December 5, 2011*

**chemistry**

If the radiicativr decay of nuclear explosion contains 90 Sr , with a half life of 28.1 years how long will it take for 99 of this radioaioot to decay
*December 5, 2011*

**chemistry**

How many grams of na cl are required to make 500ml of a 0.65 percent w/v
*December 5, 2011*

**Algebra1**

A CELL PHONE ORDDERS 500 NEW PHONES FROM A MANFACTURE.IF THE PROBABLITY OF A PHONE BEING DEFECTIVE IS 2.6% PREDICT HOW MANY OF THE PHONES ARE LIKELY TO BE DEFECTIVE.ROUND TO THE NEAREST WHOLE NUMBER
*December 5, 2011*

**Engineering**

A 2kg piece of gold metal at 90 C is placed in 5 liters (=5kg) of water at 30 C. Determine the final temperature (Tf).
*November 16, 2011*

**math**

Please show me the steps to solve this problem: The total shipping weight of two crates is 358 pounds. One crate weighs 124 pounds more than the other. What does eah crate weigh?
*October 12, 2011*

**Math**

explore the significance of the coefficient "a" in determining the shape of the graph of y=a|x|.[
*October 5, 2011*

**Math**

explore the significance of the coefficient "a" in determining the shape of the graph of y=a|x|.[
*September 13, 2011*

**english**

Crossword puzzle Try to have_________ in length and form of your sentences. 7 letters
*August 9, 2011*

**english**

Crossword puzzle Substitute lively__________ for boring, "tired" words. Has 7 letters
*August 9, 2011*

**social studies**

I need information on Obama's budget proposal and the House's budget proposal to compare and contrast. I am having trouble finding valid, easy-to-access information on both sides. Help please?
*May 24, 2011*

**math**

what does method mean
*May 23, 2011*

**College Algebra**

I figured it out. 40 minutes. Thanks anyway
*March 30, 2011*

**College Algebra**

Charlie can grade exams in 2 hours. It takes Mark 6 hours to grade the same exams. If they work together, how long will it take for them to grade the exams?
*March 30, 2011*

**music**

drbbmj
*March 7, 2011*

**Calculus**

I'm supposed to find the volume of this, I've tried it multiple times. I can't seem to get one of the possible answers. y=x+2, y=16-x^2, x=-2, x=2 A. 50.67 B. 51.67 C. 8.44 D. 16.89 E. 101.33 F. 152 Thanks for any input!
*February 24, 2011*

**Physics**

An Atwood's machine consists of masses m1 and m2, and a pulley of negligible mass and friction. Starting from rest, the speed of the two masses is 3.80 m/s at the end of 3.16 s. At that time, the kinetic energy of the system is 77.0 J and each mass has moved a distance of ...
*February 24, 2011*

**elementary math**

dffhj
*February 18, 2011*

**Math**

3fdbjnkk
*February 18, 2011*

**Calculus**

So, I need to graph (with my calculator) this out, and then find the area, and finally the volume. y=(x-1)^1/2, y=0, x=2, x=5; about the x-axis I ended up with some crazy answer like 15π/2, and I believe that's incorrect (but it might be right, idk). Any input?
*February 17, 2011*

**physics**

A 6.15 kg block slides 1.49 m down a frictionless incline that makes an angle of 60.0° with the horizontal. What is the total work done on the block
*February 17, 2011*

**Math**

When the waiter was asked to slice the 16-inch (in diameter) pizza into exactly 4 slices of equal size, he decided to do so using concentric circles rather than radial slices. Determine the radii of each of the three cuts he had to make.
*February 14, 2011*

**Math**

Let f(x)=ax^5+bx^3+cx+9, where a,b, and c are constants. If f(6)=17, determine the value of f(-6).
*February 14, 2011*

**Math**

Three brothers divide 17 candy bars. The oldest child gets 1/2, the middle child 1/3, and the youngest child 1/9. So that they do not have to cut any bars, Mom provides an extra one. The oldest child then takes 9 candy bars, the middle child 6, and the youngest 2, and they ...
*February 14, 2011*

**Math**

The letters A,B,and C represent three different digits. Determine the number ABC if ABC + ACB ---------- BCA
*February 14, 2011*

**physics**

A 70 kg painter is painting the wall of a building. He stands on a horizontal board of length 4.7 m and mass 15 kg, suspended from vertical ropes attached to each end. If the painter stands 2.0 m from one end of the board, what would the tensions in the ropes be? Near rope: ...
*December 11, 2010*

**2nd grade math**

ms. dixon
*December 7, 2010*

**AP Chemistry**

What is the structure for PCl3Br2 and 3 isomers?
*November 19, 2010*

**Geometry**

If the length of arc of measure 80 is 12 pi inches long, find the radius of the circle
*November 17, 2010*

**Chemistry**

Vinegar is a solution of acetic acid (C2H4O2) in water. Its concentration is 5.0%(w/w) and its density is 1.01 g/mL. That was the information given before the question, then it asked for the molarity of vinegar and I got .84mol/L
*November 16, 2010*

**Chemistry**

How many milliliters of pure acetic acid (density = 1.05 g/mL) would be required to prepare 1.00 L of the solution?
*November 16, 2010*

**4th grade math**

589
*November 16, 2010*

**physics**

A pendulum has a length of 1m. What is the period of this pendulum? What is the frequency of this pendulum? You measure the period of a pendulum and get 25s. What is the length of the pendulum?
*November 8, 2010*

**physics**

If a 0.1 kg mass is suspended at rest from a spring near the Earth's surface, the distance that the spring is stretched is measured to be 1.0 cm. What is the spring constant of the spring (remember the MKS units)? A mass of 2 kg is attached to a spring with constant 18 N/...
*November 8, 2010*