Wednesday

August 31, 2016
Total # Posts: 162

**chemistry**

4 Fe(s) + 3 O2(g) 2 Fe2O3(s) ΔH = -1652 kJ How much heat is released when 3.82 mol iron is reacted with excess O2?
*March 13, 2011*

**geometry**

a regular hexagon is inscribed in a circle. The radius of the circle is 18 units. What is the area of the region bounded by the inside of the circle and the outside of the hexagon. Round your answer to the nearest hundredth.
*November 30, 2010*

**geometry**

yes
*November 30, 2010*

**geometry**

obtuse triangle ABC with obtuse angle B. Point D on side AC such that angle BDC is also obtuse. Angle DAB is 2/3 of angle ABD. Angle BCD is 1/5 of angle CBD is 4 more than angle BAD. Find the measure of angle ABC.
*November 30, 2010*

**geometry**

right triangle ABC with right angle C, AC=22 and BC=6, altitude CD where D is on hypotenuse AB. What is the ratio of the area of triangle ADC to the area of triangle CDB? Write ratio as n:1 and round n to the nearest hundredth.
*November 30, 2010*

**Math**

For 0 < x < 1, let f(x) = (1 + x)(1 + x4)(1 + x16)(1 + x64)(1 + x256) · · · Compute f to the power of -1 times 8 divided by 5 times f times 3/8
*November 28, 2010*

**Math**

Let AB and CD be two lines intersecting at point O. Let OP be the bisector of angle AOC, OT the bisector of angle POB, and OR the bisector of angle TOD. If angle POR = 25 degrees, find angle AOC and angle AOD.
*November 28, 2010*

**math**

Let AB and CD be two lines intersecting at point O. Let OP be the bisector of ]AOC, OT the bisector of ]POB, and OR the bisector of ]TOD. If ]POR = 25, find ]AOC and ]AOD.
*November 28, 2010*

**math**

For 0 < x < 1, let f(x) = (1 + x)(1 + x4)(1 + x16)(1 + x64)(1 + x256) · · · Compute f−1(8/5f(3/8)
*November 28, 2010*

**math**

For 0 < x < 1, let f(x) = (1 + x)(1 + x4)(1 + x16)(1 + x64)(1 + x256) · · · Compute f−1 8 5f(3/8)
*November 28, 2010*

**math**

For 0 < x < 1, let f(x) = (1 + x)(1 + x4)(1 + x16)(1 + x64)(1 + x256) · · · Compute f−1 8 5f(3/8)
*November 28, 2010*

**math**

A battalion 20 miles long advances 20 miles. During this time, a messenger on a horse travels from the rear of the battalion to the front and immediately turns around, ending up precisely at the rear of the battalion upon the completion of the 20-mile journey. How far has the ...
*November 28, 2010*

**Finance**

A company is considering a plan that has different profit results under different conditions. Assuming there is a 20% chance of a boom and 10% chance of a recession, compute the expected value of their plan. Condition Result Boom $2,000,000 Profit Average $800,000 Profit ...
*November 15, 2010*

**economics**

A company is considering a plan that has different profit results under different conditions. Assuming there is a 20% chance of a boom and 10% chance of a recession, compute the expected value of their plan. Condition Result Boom $2,000,000 Profit Average $800,000 Profit ...
*November 15, 2010*

**english**

for classification what word goes with know,think?
*October 18, 2010*

**calculus**

Find the derivative of the functions: 1) f(x)=x(1-(2)/(x+1)) 2) f(s)=(s^2-2s+5)/(x^(1/2))
*September 23, 2010*

**Economics**

never mind its d
*June 8, 2010*

**Economics**

so is it b for # 5?
*June 8, 2010*

**Economics**

2) d 3)a 4)b 5)c 6)a
*June 8, 2010*

**Economics**

1) Which of the following is an example of a measure of labor productivity? a. Autos get 30 gallons to the mile. b. The growth rate of per capita real GDP is 3.5 percent per year. c. Farm workers produce 30 bushels of wheat per worker per day. d. Wages increase by 3.5 percent ...
*June 8, 2010*

**math**

3:4 228:x x=304 304+228=532
*April 23, 2010*

**5th grade**

is a word or phrase - "thus," "therefore" - that shows that a conclusion is up ahead
*March 13, 2010*

**computers**

. When you link a worksheet and a chart in a business report as well as on a slide, which Microsoft Office applications are integrated? A. Word, Excel, PowerPoint B. Excel, Access, Word C. Word, Access, PowerPoint D. Excel, PowerPoint, Publisher 2. Which one of the following ...
*October 24, 2009*

**Physical Science**

What type of simple machine would you use if the trees have lost their leaves and you have a lot of them to collect?
*October 11, 2009*

**12th grade**

it's C
*February 20, 2009*

**Physics**

thank you. :)
*November 24, 2008*

**Physics**

One application of the index of refraction is analysis of crime scenes. Using the index of refraction, forensic scientists can determine what type of glass has been left at a scene. Read the following and answer the questions below. Different types of glass (bottle, window, ...
*November 24, 2008*

**Physics**

A passenger bus in Zurich, Switzerland derived its motive power from the energy stored in a large flywheel. The wheel was brought up to speed periodically, when the bus stopped at a station, by an electric motor, which could then be attached to the electric power lines. The ...
*November 4, 2008*

**science**

1. A violin string is oscillating at a frequency of 880 Hz (1 Hz = 1 full cycle / second) in its 2nd harmonic. What wold be the frequency of the fundamental vibrational mode? 2. Describe how you would go about finding the frequency of an unmarked tuning fork using the ...
*July 31, 2008*

**Reseach paper**

thank you everyone for the help. I've been researching on the computer for months with no luck. i will look at the sites u recommended. i thought i was taking medical billing not a writing class....
*June 21, 2008*

**Algebra**

I am confused about how to graph two numbers on the same line. I need to graph: x</+ -2 x>/+ -4 both on the same line I have: -6 -5 [-4 -3 -2] -1 0 1 2 solid line I am not sure if I have the right [ or if I need a ( and if I need a solid line.
*March 22, 2008*

**Chemistry**

Do I have this right? Which one of these is the solute and which one is the solvent in a solution composed of a.) 25.0 g. of silver in 5.0 g. of mercury, and b.) 3.0 g. of iodine (I2) in 100.0 mL of ethanol? a.) Mercury is the solute and silver is the solvent. b.) Iodine is ...
*February 8, 2008*

**Dr. Bob**

Phenanthroline (C12H8N2) was added to the colorless prepared solution and a phenanthroline-iron (II) complex was formed. The absorbance of the resulting colored solution was measured on the spectrophotometer and the percent iron was read from a graph that had been prepared ...
*November 19, 2007*

**Dr. Bob**

Okay now can you read my introduction for me please... INTRODUCTION: This report discusses an experiment to study the percent mass of iron determined by the concentration of a colored iron solution from the absorbance of the spectrometer. This lab is designed to determine the ...
*November 19, 2007*

**Dr. Bob**

Dr. Bob can you help me get a concluding sentence to my discussion please
*November 18, 2007*

**Dr. Bob**

Another reason why the iron sample percentage didn’t match up with the box of cereals iron content may be because during the process of transferring the burned cereal to the HCL beaker some of the cereal may have been still left in the crucible. In figure B, the ...
*November 18, 2007*

**Dr. Bob**

DISCUSSION: This experiment was conducted to determine the iron content in a breakfast cereal. The results indicate 39% iron in a sample of Kix cereal. This value is slightly lower than the 43% listed on the cereal box. The difference may be attributed to the spectrometer not ...
*November 18, 2007*

**Dr. Bob**

It is still placed into the methods part
*November 18, 2007*

**Dr. Bob**

and the 0.077 was set to that because that was the lowest number I could get on spectrometer... thats why in the discussion part it said that is why there might be some error.
*November 18, 2007*

**Dr. Bob**

Okay so the five volumetric flasks came from solutions that the professor told us to get the wavelength for the highest point of absorbance for asked how I got the highest point of absorbance earlier
*November 18, 2007*

**For DrBob**

First the cuvet had to be filled with distilled water and was placed into the spectrometer and set closest to zero, the spectrometer was set for about .077, and then the volumetric flask with the solution of iron-phenanthroline was tested in the cuvet at 510.3 nm for the ...
*November 18, 2007*

**For DrBob**

After testing the five solutions in the volumetic flasks, the next step was to take the iron phenanthroline solution in the volumetric flask when it was ready to be inserted into an Ocean Optics USB2000+ Miniature Fiber Optic Spectrometer.
*November 18, 2007*

**For DrBob**

Five volumetric flasks labeled 100-500 mL were filled with sodium acetate, hydroxylamine hydrochloride, and phenanthroline and distilled water and filled to the mark on the volumetric flask. These solutions were placed one after another into the cuvet to test the wavelength ...
*November 18, 2007*

**For DrBob**

The 250 mL volumetric flask was filled with 10 mL of sodium acetate by a graduated cylinder, 1 mL of hydroxylamine hydrochloride by a micro liter pipette and 10 mL phenanthroline by a graduated cylinder. Then the volumetric flask was not to the mark so, the next step was to ...
*November 18, 2007*

**For DrBob**

Obtaining a 100 mL flask, it was place under the funnel and the liquid of cereal and hydrochloric acid was filtered out into the flask and a stopper was put on the top. The 100 mL volumetric flask with the colorless iron solution was fitted with a rubber stopper. First, ...
*November 18, 2007*

**For DrBob**

The starting materials for this lab were: a crucible, breakfast cereal (Kix), bun cent burner, 100 mL beaker, hot plate, 100 mL volumetric flask and stopper, a funnel and filter paper. First off by taking the breakfast cereal crushed up and placing it into the crucible, ...
*November 18, 2007*

**For DrBob**

Methods and Materials: The starting materials for this lab were: a crucible, breakfast cereal (Kix), bun cent burner, 100 mL beaker, hot plate, 100 mL volumetric flask and stopper, a funnel and filter paper. First off by taking the breakfast cereal crushed up and placing it ...
*November 18, 2007*

**Dr. Bob**

Can I send you my methods part again I wrote some more in there then you can see if I did it right Please :)
*November 18, 2007*

**Dr. Bob**

So should it also be introduced into to the methods part to since I had to do that as part of my methods. And you want me to put the equations into my discussion part of the lab report of each run the equations are y=mx+b or should I put that in the result part
*November 18, 2007*

**Dr. Bob**

and phenanthroline and distilled water all this was put into those flasks before my iron solution the professor wanted us to do this so we could see the wavelength on the spectrometer
*November 18, 2007*

**Dr. Bob**

Okay so I got the 39% from 5 runs on the spectrometer from volumetric flasks from 100-500 mL filled just sodium acetate,hydroxylamine hydrochloride
*November 18, 2007*

**Dr. Bob**

And here is the discussion part of the lab how would I put like a concluding sentence to this. DISCUSSION: This experiment was conducted to determine the iron content in a breakfast cereal. The results indicate 39% iron in a sample of Kix cereal. This value is slightly lower ...
*November 17, 2007*

**Dr. Bob**

Okay so I read your part on the discussion... and I added it to my discussion it just seems like I need more my professor said that the discussion part is supposed to repeat everything talked about in the previous sections like the intro,methods ect. It just sounds so ...
*November 17, 2007*

**Dr. Bob**

I need to know what else would I put into my discussion part of my lab report
*November 17, 2007*

**Dr.Bob**

I had to take cereal crush it up and place it in a crucible and cook it tell it was black ash. Then I took that burnt ceral and placed it into a beaker with HCL and water and boiled it tell the cereal was like a liquid cause coming out of the crucible it was in a circle ...
*November 17, 2007*

**For DrBob**

I had to take cereal crush it up and place it in a crucible and cook it tell it was black ash. Then I took that burnt ceral and placed it into a beaker with HCL and water and boiled it tell the cereal was like a liquid cause coming out of the crucible it was in a circle ...
*November 17, 2007*

**For DrBob**

Hey DrBob, I posted an answer to you question on my lab report just to let you know what the y= and r^2 is
*November 17, 2007*

**Calculus**

26. Find all points of inflection. f(x) = (5x-3)^(1/3) Note: I have gotten f''(x) = (-50/9)(5x-3)^(-5/3) I would like to know how to figure out the zeros.
*November 2, 2007*

**Calculus**

22. Divide the expression before differentiating. F(x) = (8x^3 - 1)/ (2x - 1) Would the way to solve this problem be... F(x) = [(8x^3) / (2x - 1)] - [(1)/(2x - 1)] = [(4x^2)/(1)] - [(1) / (2x - 1)] = (4x^2) - (2x-1)^-1 F'(x) = (8x + 1)
*October 15, 2007*

**History**

What do the 35 stars and their arrangement and the 13 strips mean on the 7th Cavalry Guidon Flag that Custer used in the battle of little big horn Thank you for using the Jiskha Homework Help Forum. On the first site you can see the flag: http://www.anyflag.com/history/cavguid...
*March 19, 2007*

**math**

an ultralight plane had been flying for 40 min when a change of wind direction doubled its ground speed. the entire trip of 160miles took 2h. how far did the plane travel during the first 40 min? Let V be the initial ground speed and 2V be the final ground speed, in miles per ...
*November 28, 2006*

**calculus**

a 20 ft ladder is leaning against a wall. The bottom is being pulled out at a constant rate of 2.5 ft/sec. Will the top of the ladder clide sown thr wall at a constant rate? What will the rate be? In relation to time? It is not constant. Use pythagorus: x^2 + y^2 = l^2, where ...
*October 12, 2006*