Saturday

April 18, 2015

April 18, 2015

Total # Posts: 1,601

**Chem**

A lake may be polluted with Pb2+ ions. what precipitation reaction might you use to test for the presense of Pb2+?
*October 9, 2011*

**Physics**

An ice sled powered by a rocket engine starts from rest on a large frozen lake and accelerates at 15.0 m/s 2 . At t1 the rocket engine is shut down and the sled moves with constant velocity v for another t2 s. The total distance traveled by the sled is 5.60 × 10 3 m and ...
*October 6, 2011*

**trig**

5 and 6
*October 5, 2011*

**math**

write the unit rate of2 into 50
*October 3, 2011*

**math**

type 8580 words in 2hrs and 45mins
*October 3, 2011*

**math**

Fator the trinomial: 4) 2 p + 10p +25 6) 2 y - 5y -24 8) 2 n + 2n -48 10) 2 y + 17y + 72 = 0 12) 2 w - 13w + 42 = 0
*September 28, 2011*

**Spanish SRAJMcGIn please recheck**

Please recheck my above posting-thank you
*September 28, 2011*

**Spanish -another question**

I'm sorry but I don't understand about #5-I should have written it as I could almost reach it so it would be Prefiero esa sepiete. Is that correct? Were the others correct I guess my closest is this/these My far away is you can almost reach them and my fathest would be...
*September 28, 2011*

**Spanish -another question**

Correction-Number 5 should be Prefiero esa serpiente. Correct because its feminine?
*September 28, 2011*

**Spanish -another question**

I'm working on distances like saying something is closest far away or furthest. Are these correct for what I put in English as the closest far away or furthest- 1.furthest away- Preferiero aquella arana.(accent over n) 2.far away-Prefiero esa gallina. 3. far away-Prefiero ...
*September 28, 2011*

**Spanish**

Thanks-appreciate it
*September 28, 2011*

**Spanish**

Change the verb in each sentence to the present participle. 1.Tú nadas. Tú estás nadando. 2. Él bebe café. Él está bebiendo café.
*September 28, 2011*

**Science**

8===))
*September 20, 2011*

**Physics**

A car is traveling 28 m/s when the driver sees a child standing on the road. He takes 0.8 s to react, then steps on the brakes and slows at 7.0 m/s2. How far does the car go before it stops?
*September 19, 2011*

**Pre-Calc**

That is so easy-I can't believe I was screwing it up so badly-Thank you
*September 18, 2011*

**Pre-Calc**

Please help me with this problem-I'm stuck (x-2)/(x+2) = (x+10)/x I'm not even sure where to start-Thanks for any help you can provide
*September 18, 2011*

**Trigonometry**

Solve. 2sin(2ƒÆ) + ã3 = 0 interval [0, 2ƒÎ) How do I start this? I feel like maybe Trig Identities, but I'm not really sure.
*September 16, 2011*

**Math trig.**

find the length of the arc intercepted by a central angle of 35 degree 28' in a circle of radius 15ft....i cant figure out how to get it ??
*September 15, 2011*

**math**

HOW TO SIMPLIFY 7 6/24?
*September 14, 2011*

**physics**

A small rock is thrown vertically upward with a speed of 13.0 from the edge of the roof of a 31.0 tall building. The rock doesn't hit the building on its way back down and lands in the street below. Air resistance can be neglected What is the speed of the rock just before ...
*September 13, 2011*

**Government**

The Principle of self-government emphasizes majority rule whereas the principle of liberty emphasizes individual rights. There principles A. are universal and are the foundation of all legitimate governments. B. have no real meaning in practice. C. have the same meaning for ...
*September 11, 2011*

**Math**

Evaluate if r=-8: |-15-r|+|r|=
*September 9, 2011*

**chemistry**

1.1
*September 5, 2011*

**algebra**

Factor: A.) 2x^2-9x-18 B.) 14x^2-55x-36 C.) x^3+3x^2-x-3
*September 3, 2011*

**physics**

A student uses a sonic motion detector to determine the position of a car at various times. The student takes five positions at five different times. The student's data is represented below: Time t [s] Position x [m] 0.5 39.9 1.4 75.4 2.9 139.3 3.7 186.5 4.1 193.2 (a) Plot...
*August 30, 2011*

**physics**

An object moves to the right according to the equation x = 4t2 + 3t + 16 where x is in meters and t is in seconds. Determine the object's average velocity between time t = 0 and time t = 4 seconds.
*August 30, 2011*

**science**

1. what weight in grams of magnesium oxide will produce from burning 96 grams of magnesium? 2. a solution containing 252g of calcium sulfate will produce from 165lbs of phosphate rocks containing 82.5 % pure calcium phosphate treated with sulfuric acid? 3. how many tons of ...
*August 28, 2011*

**Calculus**

find tha value of f(x)=x3 where f(x+h)-f(x)/h so far I got 3x2+3hx+h2/h and got stuck from here.
*August 27, 2011*

**science**

1. What weight of aluminum may be obtain from 1 kg of aluminum oxide? 2. how many liters of hydrogen would be form by the reaction of 25g of hydrochloric acid and sufficient quantity of zinc? 3. 0.82l of an unknown gas at 35 degree Celsius and 80 cm-Hg weigh 2.46g. compute for...
*August 27, 2011*

**Calculus**

I am having trouble with these 2 problems. Evaluate: (1/x^9)dx Evaluate: (5x^5-4x^3+6x)dx
*August 26, 2011*

**Calculus**

Sorry, I typed wrong. The equation is (3x^4-2x^3+7x)/x^4+14x-2
*August 26, 2011*

**geometry**

find the value of b if jm = b and ml = 3b-4
*August 24, 2011*

**statistics**

A researcher is interested in studying people’s mean age in a certain region. If the population standard deviation is known to be 8 years and 1.5 year of error margin is allowed, find the minimum simple size the researcher needs to use, knowing that he is going to conduct...
*August 24, 2011*

**biology**

what is the difference between a chemical that is an irritant compared to a chemical that is corrosive?
*August 21, 2011*

**Web Design**

how has the internet changed since 1980?
*August 19, 2011*

**Calculus**

put function in standard form f(x)=-4x^2-32x+9
*August 3, 2011*

**Calculus**

put in standard form: 4x^2=36+9y^2
*August 1, 2011*

**Calculus**

If $22,550 is invested at 2.95% compounded continuously, how long will it take to reach $50,000 in the account?
*August 1, 2011*

**Calculus**

8-3i divided by -4-6i=
*August 1, 2011*

**Calculus**

Need help with this complex number equation. 8-3i/-4-6i=
*July 30, 2011*

**Calculus**

how to convert this from rectangular to polar? r=cos theta
*July 29, 2011*

**Math**

Use Mathematical Induction to show that the statement 2 + 6 + 10 + . . . + (4n – 2) = 2n^2 is true
*July 29, 2011*

**Calculus**

How can I convert polar coordinates to rectangular coordinates?
*July 29, 2011*

**Chemistry**

If a buffer solution is 0.200M in a weak acid (Ka=1.6*10^-5)and 0.480 M in its conjugate base what should the pH be?
*July 26, 2011*

**Chemistry**

If the Ka of a monoprotic weak acid is 4.3*10^-6, what is the pH of a 0.16 M solution of this acid?
*July 24, 2011*

**Chemistry**

calculate the pH and the pOH of an aqueous solution that is 0.035 M In HCI and 0.080 M in HBr?
*July 23, 2011*

**Chemistry**

At a certain temperature, 0.660 mol of SO3 is placed in a 3.00 L container. 2SO3=>2SO2+O2 Kc=
*July 23, 2011*

**Pre Calculus**

If $22,550 is invested at 2.95% over 10 years, describe the amount of the investment if interest is compounded a. Every 2 months equation: -A(t)=Ao(1+i/n)n*t
*July 21, 2011*

**Calculus**

Use the Law of sines to find the remaining sides. 1. a=40 degrees; Beta=87; c=115
*July 20, 2011*

**Chemistry**

What is the ph of 2.5 M solution of HClO4?
*July 20, 2011*

**Chemistry**

True or false 1. The energy of a collision between atoms or molecules must be greater than the activation energy for bonds to be broken? 2. Decreasing the temperature decreases the kinetic energy of the reactant, and the reaction goes more slowly? 3. two or more atoms must ...
*July 19, 2011*

**Chemistry**

Hi. How would I determine the rate constant of a reactant?
*July 19, 2011*

**Chemistry**

The rate constant for this first order reaction is 0.0470s-1 at 400 C. A to products After how many secs will 11.0% of the reactant remain?
*July 19, 2011*

**Chemistry**

The rate constant for this first order reaction is 0.440s-1at 400 C. A to products How long(in seconds) would it take for the concentration of A to decrease from 0.740 M to 0.290 M?
*July 19, 2011*

**Calculus**

find the exact value of sin 11pi/12 using the sum or difference formula.
*July 19, 2011*

**phys science**

A space shuttle orbits at an altitude of approximately 200km above the surface of the Earth. If the radius of the Earth itself is 6380 km, what’s the acceleration due to gravity at the altitude of the space shuttle?
*July 18, 2011*

**calculus **

Verify the identity cot2 beta/1+csc beta=1-sin beta/sin beta.
*July 17, 2011*

**Chemistry**

No its not a typo but I did put the wrong activation energy. Its suppose to be a certain reaction has an activation energy of 37.70kj/mol. At what kelvin temperature will the reaction proceed 3.00 times then it did at 303k? I was working the problem and got stuck on finishing ...
*July 17, 2011*

**Chemistry**

No its not a typo but I did put the wrong activation energy. Its suppose to be a certain reaction has an activation energy of 37.70kj/mol. At what kelvin temperature will the reaction proceed 3.00 times then it did at 303k? I was working the problem and got stuck on finishing ...
*July 16, 2011*

**Chemistry**

A certain reaction has an activation energy of 37.30 kj/mol. At what Kelvin temperature will the reaction proceed 3.00 times then it did at 303 k?
*July 16, 2011*

**Chemistry**

After 79 mins 20.0% of a compound has decomposed. What is the half life of this reaction assuming first-order kinetics?
*July 16, 2011*

**Chemistry **

The rate constant for this first order reaction is 0.0470 s-1 at 400 C. A TO Products After how many seconds will 11.0% of the reactant remain?
*July 16, 2011*

**Chemistry**

The rate constant for this first-order reaction is 0.440 s-1 at 400 C. A to products How long in seconds would it take for concentration of A to decrease from 0.740 M 0.290 M?
*July 16, 2011*

**Chemistry**

Determine the average rate of change of B from t=0s to t=352s. A to 2B Time Concentration of A (M) 0 0.670 176 0.385 352 0.100
*July 16, 2011*

**Chemistry**

Determine the average rate of change of B from t=0s to t=352s. A to 2B Time Concentration of A (M) 0 0.670 176 0.385 352 0.100
*July 16, 2011*

**Chemistry**

The rate of the following reaction is 0.480 M/s. What is the relative rate of change of each species in the reaction? A+3B=2C
*July 16, 2011*

**Pre Calculus**

use the sum of difference formula what is sin(pi/2-5pi/3)?
*July 14, 2011*

**Chemistry**

at 298 k, the Henry's law constant for oxygen is 0.00130 M/atm. Air is 21.0% oxygen. at 298 k, what is the solubility of oxygen in water exposed to air at 1.00 atm?
*July 12, 2011*

**Chemistry**

The boiling point of an aq solution 102.11 C. What is the freezing point?
*July 12, 2011*

**Chemistry **

The boiling point of an aq solution 102.11 C. What is the freezing point?
*July 12, 2011*

**Chemistry **

A solution of H2SO4 with a modal concentration 6.25m has a density of 1.300 g/ml. What is the molar concentration?
*July 12, 2011*

**Chemistry**

what is the mole fraction of solute molality concertration for an aqueous solution that is 19% NaOH by mass?
*July 12, 2011*

**Calculus**

Given f(x)=-10x2-42x-17 find f(x+h)
*July 11, 2011*

**Calculus **

Express the quadratic function y=-2/3x2-12x-11 in standard form?
*July 11, 2011*

**Calculus**

Given m(x)=7/5x2+9-2 what is the domain of m in set notation form?
*July 11, 2011*

**physics**

A spring-loaded toy gun is used to shoot a ball of mass m straight up in the air. The spring has spring constant k. If the spring is compressed a distance x_0 from its equilibrium position ( y = 0 ) and then released, the ball reaches a maximum height h_max (measured from the ...
*July 9, 2011*

**Chemistry**

1. The vapor pressure, P of a certain liquid was measured at two temperatures, T. from this data: T(K) and P(kpa) 275 3.57 825 6.57 for the enthalpy how would this be plotted on the graph point 1: point 2: 2. What is the rise, run, and slope 3. What is the enthalpy of ...
*July 9, 2011*

**Chemistry**

1.The density of solid Fe is 7.87 g/cm3. What volume per atom of Fe? 2.As a solid Fe adopts a body centered cubic unit cell. What is the volume of a unit cell of this metal? 3.What is the edge length of a unit cell of Fe?
*July 9, 2011*

**Chemistry**

A certain substance has a heat of vaporation 56.21 kj/mol. At what kelvin temperature will the vapor pressure be 6.50 times higher than it was at 361k? I need help in setting the problem: I got 56.21/8.3145j/mol.k(1/T1-1/T2)?
*July 9, 2011*

**Chemistry **

x+y=9.0 0.50x+0.20y=3.90 What is the value of x and y?
*July 9, 2011*

**Chemistry practice**

My mistake I meant x+y=9.0 0.50x+0.20y=3.90 What is the value of x and y?
*July 9, 2011*

**Chemistry practice**

x+y=9.0 0.50+0.20y=3.90 What is the valuse of x and y?
*July 9, 2011*

**Chemistry**

A certain substance has a heat of vaporation 56.21 kj/mol. At what kelvin temperature will the vapor pressure be 6.50 times higher than it was at 361k? Thank you
*July 9, 2011*

**Chemistry**

A certain substance has a heat of vaporation 56.21 kj/mol. At what kelvin temperature will the vapor pressure be 6.50 times higher than it was at 361k? Thank you
*July 9, 2011*

**Chemistry**

A certain substance has a heat of vaporation 56.21 kj/mol. At what kelvin temperature will the vapor pressure be 6.50 times higher than it was at 361k? Thank you
*July 9, 2011*

**Chemistry**

Two 20.0g ice cubes at -10.0 C are placed into 275g of water at 25.0 C. Assuming no energy is transferred to or from the surroundings, calculate the final temperature of the water after all the ice melts.
*July 9, 2011*

**Chemistry **

Calculate the heat energy released when 19.6 of liquid mercury at 25.00 C is converted to solid mercury at its melting point
*July 9, 2011*

**Algebra 2**

Simplify: a+1/a-1 times a^2-1/(a+1)^2
*July 4, 2011*

**Algebra 2**

Simplify: (x^3-4x)(x^2-4x+4)^-1
*July 4, 2011*

**College Physics**

All of your math is correct except that h is just 36.7 because the bungee is attached to his feet not halfway up his body. Therefore his potential energy has to be measured to that point. Then you get mgh=1/2kx^2 k=(2mgh)/x^2 k=(2*93.1*9.8*36.7)/9.3^2 = 774.29 N/m
*June 29, 2011*

**calculus**

2x^3+3x^2-12x-7 the absolute maximum. I need help because it seems no one else in my class knows how to.
*June 28, 2011*

**Physics**

Hey, it's me again, Can someone help me with this question? A water balloon is dropped from the top of a building. Assume the balloon does not break when it strikes the ground. If the water balloon falls a distance of 21m, what is the maximum temperature rise of the water ...
*June 28, 2011*

**Physics**

"The energy that is transferred as heat to or from the object with the larger heat capacity must be greater than the energy that is transferred as heat to or from the object with the smaller heat capacity." Can someone explain why this concept is true or false?
*June 21, 2011*

**writing**

thank you those helped a lot! thanks!
*June 20, 2011*

**writing**

i need help on a theme statement for "cask of amontillado"
*June 20, 2011*

**Math**

A rectangular lot is to be fenced using 80m of fencing. What is the maximum area and what are the dimensions of the lot?
*June 19, 2011*

**chemistry**

1. 15.0 g of sodium sulfate are dissolved in water to form 400.0 g of solution. The density of the solution is 1.056 g/mL at 25oC. a. What is the mass percent (%(w/w)) of sodium sulfate? b. What is the molarity of sodium sulfate? c. What is the molarity of the sodium ion? d. ...
*June 13, 2011*

**Information Technology**

I have this assignment due tonight in about 2 and a half hours. I am going to try to finish it the best that I can but I do not know if I will be able to. I really am stuck. I have no idea where to even start on this. Can somebody please help?! • Read the following ...
*May 28, 2011*

**math**

0.8T = 24
*May 24, 2011*