Saturday

April 18, 2015

April 18, 2015

Total # Posts: 6,578

**Chemistry**

Given the following hypothetical equations, 2A + B → 3C + 2D ΔH = -46.7kJ C → B ΔH = 13.1kJ 2E → B ΔH = 84.5kJ, what is the enthalpy change (kJ) for the following reaction? A → D + 2E
*March 7, 2012*

**Chemistry**

Thanks for all the help Bob!
*March 7, 2012*

**Chemistry**

The molar mass of an unknown salt is 63.5. If 4.81 g is added to 81.1 mL of water the temperature changes from 20.95oC to 21.62oC. What is the molar heat of solution (J/mol) of the salt? (Assume all of the heat is transfered to the water) Express your answer to the nearest ...
*March 7, 2012*

**Chemistry**

What kind of orbital is designated by the quantum numbers (3,1,1,1/2)? Answer s, p, d, or f only.
*March 7, 2012*

**math**

123/3=41. 41*2=82 students
*March 7, 2012*

**4th grade math**

4 out of 5 because there are 5 total marbles, and 4 are blue. Thus the probability is 4/5. Your answer should be d. not here.
*March 7, 2012*

**Biology**

Try a bar graph with type of medication on the y axis and time in hours on the x axis. Your bars will be horizontal.
*March 7, 2012*

**US HISTORY**

Thank u very much
*March 7, 2012*

**US HISTORY**

thank u, are there any others because my teacher said almost 5 of em
*March 7, 2012*

**US HISTORY**

How does Prohibition on alcohol during the 1900's affect today life
*March 7, 2012*

**calculus**

If 0 degrees < x < 180 degrees, what values of x, to the nearest degree, are the solution to the equation 2tan to the square x + 5tanx - 12 = 0
*March 7, 2012*

**calculus**

For part B, your figure there is an ellipsoid, x^2+y^2+z^2=4, so the domain should be (x,y,z):X<4,y<4,z<4
*March 7, 2012*

**calculus**

f'(x)=3x^2+2xy^2+1 f'(Y)=2x^2+3y^2+1 f'(xy)=4xy f'(yx)=4xy
*March 7, 2012*

**Math**

You are correct on the time, but it needs to be simplified if not put into decimal form. Now you need to plug in 2 into the orignal problem and get a resultant, then plug in three to the original problem as well. If they are the same resultant then they follow rolles theorem. ...
*March 7, 2012*

**Chemistry **

If 14.0 kilograms of Al2O3(s), 57.4 kilograms of NaOh(l), and 57.4 kilograms of HF(g) react completely, how many kilograms of cryolite will be produced?
*March 6, 2012*

**Calculus-derivatives**

Yes for both. Growth and decay problems are awful, just letting you know
*March 6, 2012*

**math**

Plug 10 into the x value. f(10)=7(10)+8 F(-6)=7(-6)+8 and so on...
*March 6, 2012*

**calculus**

dy/dx= [5x^4e^(x^4)+4x^3*e^(x^4)*5x^4]* [(x^5)(e^(x^4)]
*March 6, 2012*

**Singapore Math**

still confused
*March 6, 2012*

**Pre-Cal**

Get you a ti-83 and graph it...should show you all of this
*March 6, 2012*

**Calculus**

Since you have found your derivative you then need to move on and find its critical values(where the derivative equals zero). Then if those numbers are within the interval [1,4] you must also plug those into your orignal function. If they do not, then they should be ...
*March 5, 2012*

**Trig**

(sinxcosy+cosxsiny)(sinxcosy-cosxsiny)= Then, foil those and your middle two terms should cancel out leaving you with sin^2xcos^2y-cos^2xsin^2y= now using the pythagereom theorem change all the sin^2's to cos^2 giving you cos^2y-cos^2xcos^2y-[cos^2xcos^2xcos^2y]= cos^2y-...
*March 5, 2012*

**Trig**

First off these are usually not this hard...just saying...ill be changing your alphas to x's and your betas to y's we will work with the left side because it is easier. use identity sum and difference sin(x+y)sin(x+y)=cos^2y-cos^2x s
*March 5, 2012*

**Trig**

its the square root of 49+121
*March 5, 2012*

**math (Ms.Sue)**

you are correct
*March 5, 2012*

**trig**

a). secx=-2 2pi/3 and 4pi/3 b). sinx=(2^(1/2)/2 its that value at pi/4, and 3pi/4 c). cosx=+ or - 1, so if they want multiple answers its 0, 2pi, and pi
*March 5, 2012*

**math**

A rectangle has width w and its length is 4 units longer than 2 times the width, or 2w + 4 . Write a polynomial for the area of the rectangle.
*March 5, 2012*

**Algebra**

A rectangle has width w and its length is 4 units longer than 2 times the width, or 2w + 4 . Write a polynomial for the area of the rectangle.
*March 5, 2012*

**calculus**

e^x+-2xe^-x^2
*March 4, 2012*

**calculus**

Consider the curves y = x^2and y = mx, where m is some positive constant. No matter what positive constant m is, the two curves enclose a region in the first quadrant.Without using a calculator, find the positive constant m such that the area of the region bounded by the ...
*March 4, 2012*

**Advanced Algebra**

John is making a sundae. If there are 13 flavors of ice cream, 9 different toppings, and 4 types of nuts, how many different sundaes can he make if he chooses one of each?
*March 4, 2012*

**Algera**

Ms. Pecho currently owes $637.50 simple interest on a loan of $2500 at a anual inteest ate of 17%. How long has she had the loan?
*March 1, 2012*

**Career**

What are the best ways to market a insurance and risk management company? business sells paper and promises, I can't give discounts and I don't have control of the cost of the insurance or how claims are handled.
*March 1, 2012*

**marketing2**

explain what i have to do with this assignment?
*March 1, 2012*

**Physics Please help!**

Calculate the position of the center of mass of the following pairs of objects. Use acoordinate system where the origin is at the center of the more massive object. Give youranswer not in meters but as a fraction of the radius as requested. Get data from insidethe front cover ...
*February 28, 2012*

**Geometry**

(3X2)x2+(2x7.5)x2+(3X7.5)x2= surface area 3x2x7.5= volume
*February 28, 2012*

**Physics**

Calculate the position of the center of mass of the following pairs of objects. Use acoordinate system where the origin is at the center of the more massive object. Give youranswer not in meters but as a fraction of the radius as requested. Get data from insidethe front cover ...
*February 28, 2012*

**geometry**

10/(cos(50))=length of ladder
*February 28, 2012*

**math**

Abe has 9 pens. How many more pens does Abe need to have 12 pens. Write an equation.
*February 28, 2012*

**college algebra**

You are given the XY coordinates. Take Time to be X, and Temperature to be Y. Create a graph on a Cartesian coordinate system. A) If done correctly your linear Regression should be Y=-10X + 2350. B) Your slope is -10. Meaning that for every 1 minute the pottery cools by 10 ...
*February 28, 2012*

**Taxes**

In the US, we have a progressive tax system, which means higher incomes are taxed at a higher rate. But capital gains are not - they are taxed at a flat rate of 15%. This is an example of an institution, a formal "payment" rule, that affects the "tax game"...
*February 28, 2012*

**Student**

lmao, I just literally lol'ed at those comments.
*February 27, 2012*

**statistics**

In this unit we have worked with scores and their locations within a distribution. This discussion is designed to get you to think a little more about distributions of scores. Shown below are two samples of scores. Input these scores into SPSS and use plots and data ...
*February 26, 2012*

**Chemistry**

38
*February 26, 2012*

**physics**

A ball rolls with a speed of 4.4 m/s toward the edge of a table that is 1 m above the floor. The ball rolls off the table. a. How long is it in the air? s b. How far out from the edge of the table does the ball hit the floor? m
*February 25, 2012*

**math**

What is the angle formed if there is a rise of 10 inches over a run of 57 inches?
*February 25, 2012*

**physics**

Find the gravitational force exerted by a 0.515 kg mass on a 0.108 kg mass 1.94 m away.
*February 24, 2012*

**physics**

Find the acceleration of the block of mass M = 4.79 kg (m = 4.03) (KE = 0.1)
*February 24, 2012*

**physics**

A person of mass 84.5 kg is initially at rest on the edge of a large stationary platform of mass 150 kg, supported by frictionless wheels on a horizontal surface. The person jumps off the platform, traveling a horizontal distance of 1.00 m while falling a vertical distance of ...
*February 24, 2012*

**physics**

A skater of mass 74.0 kg initially moves in a straight line at a speed of 4.60 m/s. The skater approaches a child of mass 45.0 kg, whom he lifts on his shoulders. Assuming there are no external horizontal forces, what is the skater's final velocity?
*February 24, 2012*

**physics**

A bowling ball weighing 43.0 N initially moves at a speed of 4.90 m/s. How long must a force of 51.0 N be applied to the ball to stop it?
*February 24, 2012*

**geometry**

if a painting has a perimeter of 36 in, and the length of the picture is 8 inches. then what is the width?
*February 23, 2012*

**Physics**

Biomedical measurements show that the arms and hands together typically make up 13.0% of a person's mass, while the legs and feet together account for 37.0% . For a rough (but reasonable) calculation, we can model the arms and legs as thin uniform bars pivoting about the ...
*February 23, 2012*

**Economics**

B. Suppose there are two goods, Cloth and Food, and two factors of production, labour and capital. Suppose that the production function for each good is "homothetic". Put capital K in the vertical axis and labour L in the horizontal axis. For Cloth production, for ...
*February 23, 2012*

**Physics help please!!!**

Biomedical measurements show that the arms and hands together typically make up 13.0% of a person's mass, while the legs and feet together account for 37.0% . For a rough (but reasonable) calculation, we can model the arms and legs as thin uniform bars pivoting about the ...
*February 23, 2012*

**calculus**

Evaluate the integral S x/(sqrt(3x-1))dx Use U-Substitution method.
*February 23, 2012*

**College Algebra 1050**

Assume you are on a planet with a gravity constant g (instead of 32 feet per second squared) and a speed of sound c (instead of 1100 feet per second), and that you hear the impact of the rock after t seconds. Then the depth of the well is x feet, where your answer depends on g...
*February 22, 2012*

**math**

Three pennies are tossed into the air.What is the probability they will match either heads-heads-heads or tails-tails-tails when they land?
*February 22, 2012*

**math**

One estimate for the distance from earth to the andromeda galaxy is 2,400,000 light years. What is this distance expressed in scientigic notation?
*February 22, 2012*

**math**

jasmine bought 26 pieces of fruit.she bought 6 oranges.she bought twice as many apples as oranges,and twice as many oranges as bananas.she also bought some pears.
*February 22, 2012*

**calculus**

Differentiate both sides of the double angle identify sin 2x= 2 sin x cos x to determine an identify for cos x. Find the first derivative, second derivative, third fourth, fifth, sixth, seventh and eighth derivative. Use the results to find the twelfth and fifteenth derivative...
*February 21, 2012*

**chemistry**

In a lab experiment I added Br2 to hydrocarbons cyclohexane, cyclohexene, and toluene. A loss of color would indicate a reaction took place. Only the cyclohexene lost color and turned clear. I guess this means that the Br2 broke the cyclohexenes double bonds but why didn't...
*February 20, 2012*

**chemistry- solubility**

hydrocarbons nhexane, cyclohexane, and toluene are are insoluable in H2O (i assume because the hydrocarbons are non polar and water is polar) but why are these three hydrocarbons soluable in CH2Cl2?
*February 20, 2012*

**pre-cal**

a) S=cA^k b) A=2Ao K=2 S=c(2Ao)^2=c*2^2*Ao^2 S=4cAo^2 therefor the # of species increased by 4.
*February 19, 2012*

**Visual Literacy**

What are the factors that determine whether or not a print design can be classified as "good design?"
*February 18, 2012*

**Algebra**

STILL DONT GET THIS can anyone explain me this please a cylinder has a volume of 19cm^3. If the radius is doubled, what is the volume of the new cylinder? HOW TO DO THIS
*February 18, 2012*

**Algebra**

so answer is 1216
*February 18, 2012*

**Algebra**

a cylinder has a volume of 19cm^3. If the radius is doubled, what is the volume of the new cylinder? HOW TO DO THIS
*February 18, 2012*

**Calculus**

An infinite number of points lie on the curve and there is a tangent line at every point. So may they were asking how many times the tangent not exists. The tangent would not exist if the derivative was undefined at some point. Since the derivative is a polynomial it is ...
*February 18, 2012*

**Calculus**

v(t)=s'(t)=150-32t set s(t)=200 find out when the rock is 200 feet above the ground. 200=150t-16t^2 t=(5/16)+or-(15-sqrt(97)) 0=150t-16t^2 t=75/8 not 0 because it started on the ground the velocity when it strikes the ground is v(75/8)=-150 the other velocity is v((5/16)+...
*February 18, 2012*

**artist**

What inspired Pablo Picasso to paint Weeping woman? Please give some historical context. Thanks
*February 18, 2012*

**Physics help please!!!**

so 570rpm*2pirad = 3581.415625 i divide that with rev*1min/60 sec == 59.69 is that correct ??
*February 18, 2012*

**Physics help please!!!**

The angular speed of digital video discs (DVDs) varies with whether the inner or outer part of the disc is being read. (CDs function in the same way.) Over a 133 min playing time, the angular speed varies from 570 rpm to 1600 rpm. Assuming it to be constant, what is the ...
*February 18, 2012*

**physics**

Consider a frictionless track as shown in the figure below. A block of mass m1 = 4.20 kg is released from A. It makes a head on elastic collision at B with a block of mass m2 = 9.00 kg that is initially at rest. Calculate the maximum height to which m1 rises after the collision.
*February 17, 2012*

**Geometry**

140
*February 17, 2012*

**Physics please help its urgent i need help **

A crate of oranges weighing 209 N rests on a flatbed truck 2.0 m from the back of the truck. The coefficients of friction between the crate and the bed are μs = 0.41 and μk = 0.20. The truck drives on a straight, level highway at a constant 7.5 m/s. (a) What is the ...
*February 16, 2012*

**Physics to drwl please help**

A crate of oranges weighing 209 N rests on a flatbed truck 2.0 m from the back of the truck. The coefficients of friction between the crate and the bed are μs = 0.41 and μk = 0.20. The truck drives on a straight, level highway at a constant 7.5 m/s. (a) What is the ...
*February 16, 2012*

**Social Studies**

D I think
*February 16, 2012*

**Wow is there no one to help with physics???**

I got the rest bobpursley but for some reason am not getting the right answer for part b which friction=ma but when i put 209(2.1) the answer isnt right
*February 16, 2012*

**Wow is there no one to help with physics???**

Thanks bobpursley
*February 16, 2012*

**Wow is there no one to help with physics???**

How would you know its all me?
*February 16, 2012*

**Wow is there no one to help with physics???**

A crate of oranges weighing 209 N rests on a flatbed truck 2.0 m from the back of the truck. The coefficients of friction between the crate and the bed are μs = 0.41 and μk = 0.20. The truck drives on a straight, level highway at a constant 7.5 m/s. (a) What is the ...
*February 16, 2012*

**Physics helppp**

A crate of potatoes of mass 9.0 kg is on a ramp with angle of incline 30° to the horizontal. The coefficients of friction are μs = 0.69 and μk = 0.41. Find the frictional force (magnitude and direction) on the crate if the crate is at rest. magnitude N? thanks
*February 16, 2012*

**math**

Thank you very much. That is what I thought it was, but I wasnt sure.
*February 16, 2012*

**math**

You are designing a rain gutter made from a piece of sheet metal that is 1 foot by 5 feet. The gutter is formed by turning up two sides. You want the rain gutter to have the greatest volume possible. Below is the polynomial function that represents the volume of the gutter. ...
*February 16, 2012*

**math**

2/3+7/9
*February 15, 2012*

**math**

2,500
*February 15, 2012*

**Calculus (Integrals and Derivatives)**

It would be -28. For future notice, the integral is going from the interval -3 to 1(from point a to b)...this information will come in handy if you have to take physics
*February 15, 2012*

**Physics**

Locomotive exert on a 12560-kg boxcar to make it accelerate forward at 0.38 m/s2. How long will it take the boxcar to reach its cruising speed of 112 km/h (69.6 mph or 31.1 m/s)?
*February 15, 2012*

**Math**

If I financed a computer that costs $1500. If the simple interest rate is 21%, how much will the I owe after one month if no payments are made?
*February 15, 2012*

**math: elapsed time**

um any other websites
*February 15, 2012*

**math: elapsed time**

somebody answer this question, i really need help!
*February 15, 2012*

**math: elapsed time **

i need a website that would teach me every thing about elapsed time. it's really kind of confusing to me
*February 15, 2012*

**11Science**

Inherited traits
*February 15, 2012*

**math**

so it would be like, 5/8 ? 6/7 8,16,24,32,40,48,56,64 7,14,21,28,35,42,49,56 LCD IS 56 so now i do 56/7=8*6=48 6/7=48/56 56/8=7*5=35 so, 5/8=35/56 5/8 (35/56) < 6/7 (48/56)
*February 14, 2012*

**math**

so it's like you do this -> 2,4,6,8,10,12 3,6,9,12,15,18,21 4,8,12,16,20 and one more question, what about the numerators? like if you're comparing 3/8 to 2/5 the common multiple is 40. the numerators?
*February 14, 2012*

**math**

how do you change them into equivalent decimals and same denominators?
*February 14, 2012*

**math**

how to you compare 8 fractions with different denominators including improper fractions?
*February 14, 2012*

**Chemistry**

How would you prepare 10.0 Liters of a solution that was 20 parts per million sodium perchlorate in water? What would be the molarity of the solution (assume density is 1.0 g/mL and 1ppm=1 mL/L)?
*February 14, 2012*

**Social Studies 7R - DBQ Essay Check**

yes. really n.o.c
*February 13, 2012*