Thursday

December 18, 2014

December 18, 2014

Number of results: 18,745

**chemistry**

How can i calculate the concentration of each ions remaining in the solution after precipitation is complete? ok heres the full question:: 2KOH + Mg(NO3)2 -------------> 2KNO3 + Mg(OH)2 a 100.0 mL aliquot of 0.200 M aqueous potassium hydroxide is mixed with 100.0mL of 0....
*August 23, 2010 by Crickett*

**chemistry**

How can i calculate the concentration of each ions remaining in the solution after precipitation is complete? ok heres the full question:: 2KOH + Mg(NO3)2 -------------> 2KNO3 + Mg(OH)2 a 100.0 mL aliquot of 0.200 M aqueous potassium hydroxide is mixed with 100.0mL of 0....
*August 24, 2010 by Crickett*

**Chemistry**

How can i calculate the concentration of each ions remaining in the solution after precipitation is complete? ok heres the full question:: 2KOH + Mg(NO3)2 -------------> 2KNO3 + Mg(OH)2 a 100.0 mL aliquot of 0.200 M aqueous potassium hydroxide is mixed with 100.0mL of 0....
*August 24, 2010 by Crickett*

**Chem**

A solution is made by dissolving 26.9 g of NaOH in approximately 450 mL of water in a volumetric flask. The solution becomes quite warm, but after it is allowed to return to room temperature, water is added to total 500 mL of solution. Calculate the pH of the final solution. ...
*February 27, 2013 by Anonymous*

**Math-DrBob222**

Healthy food Inc sells 50lb bags of grapes to the military for $10 a bag. The fixed costs of this operation are $80,000 while the variable costs of the grapes are $10 per lb. 1.Calculate the profit or loss on 12,000 bags and on 25,000 bags. Can you please walk me through on ...
*July 11, 2009 by janay1978*

**Phyiscs **

Please show work You decide to take a nice hot bath but discover that your thoughtless roommate has used up most of the hot water. You fill the tub with 270 kg of 30.0°C water and attempt to warm it further by pouring in 5.00 kg of boiling water from the stove. (a) Is this a ...
*July 15, 2010 by Anonymous*

**Physicss **

Please show work You decide to take a nice hot bath but discover that your thoughtless roommate has used up most of the hot water. You fill the tub with 270 kg of 30.0°C water and attempt to warm it further by pouring in 5.00 kg of boiling water from the stove. (a) Is this a ...
*July 15, 2010 by Anonymous*

**PChem**

For the gas phase reaction 2NO2 + F2 ¨ 2NO2F, the rate constant is k= 38 dm3/mol-s at 27 oC. The reaction is first-order in NO2 and first-order in F2. A) Calculate the number of moles of NO2, F2, and NO2F after 10.0 s if 2.00 mol of NO2 is mixed with 3.00 mol of F2 in a 400 ...
*December 9, 2014 by Debora*

**Chemistry**

5.0 g of NaNO3 is dissolved in 50.0 g of water. The initial temperature of the water was 21 degrees Celsius and the final temperature of the water is 15.7 degrees Celsius. 1)Calculate the heat of solution, DeltaHsolution. 2) calculate the heat of solution, DeltaHsolution, per ...
*October 19, 2009 by Tom*

**Chemistry**

5.0 g of NaNO3 is dissolved in 50.0 g of water. The initial temperature of the water was 21 degrees Celsius and the final temperature of the water is 15.7 degrees Celsius. 1)Calculate the heat of solution, DeltaHsolution. 2) calculate the heat of solution, DeltaHsolution, per ...
*October 19, 2009 by Tom*

**chemistry**

5.0 g of NaNO3 is dissolved in 50.0 g of water. The initial temperature of the water was 21 degrees Celsius and the final temperature of the water is 15.7 degrees Celsius. 1)Calculate the heat of solution, DeltaHsolution. 2) calculate the heat of solution, DeltaHsolution, per ...
*October 19, 2009 by Tom*

**Chemistry - please this is urgent**

To a calorimeter containing 41.80g of water at 29.95oC, 11.7999 of a salt was added with stirring. As the salt dissolved, the temperature rapidly changed to 37.85oC before slowly returning to room temperature. 1. Calculate the Heat of Solution. Given that the Heat of Formation...
*March 14, 2008 by girl who needs help in chemistry right now*

**physics**

1. Calculate the frequency (Hz) and energy (eV) of green photons with wavelength of 555nm. Photon energy = hν, where ν = frequency in Hz and h = 6.626x10-34 joule-sec, the Planck’s constant. Keep in mind that: wavelengthxfrequency = speed. 2. Andy Ruddick can serve ...
*March 1, 2009 by JeFF*

**physics**

a block of mass 2 kg and block B of mass 8 kg are connected by a spring of spring constant 80 N/m and negligible mass. The system is being pulled to the right across a horizontal frictionless surface by a horizontal force 4 N with both blocks experiencing equal constant ...
*June 9, 2008 by shelly*

**Physical Science**

A 28.0kg block is connected to an empty 1.80kg bucket by a cord running over a frictionless pulley. The coefficient of static friction between the table and the block is 0.41 and the coefficient of kinetic friction between the table and the block is 0.35. Sand is gradually ...
*September 28, 2009 by Brittany*

**statistics**

Suppose a new treatment for a certain disease is given to a sample of n=200 patients. The treatment was successful for 166 of the patients. Assume these patients are representative of the population of individuals who have this disease. (a) Calculate the sample proportion of ...
*April 5, 2012 by Kya*

**Physics**

I'm supposed to to calculate an experimental value for the acceleration of gravity from the slope of an acceleration vs. delta mass graph... also i'm supposed to find the percent error (to the normal acceleration of gravity of 9.8).. the slope is .442 i'm not sure how to do ...
*October 30, 2014 by Amber*

**Physics**

Calculate the effective value of g, the acceleration of gravity, at 6400m , above the Earth's surface. Calculate the effective value of g , the acceleration of gravity, at 6200km , above the Earth's surface
*October 2, 2009 by Lea*

**Physical Chemistry**

A 100 amino acid folded protein (F) is in equilibrium with it’s unfolded (U) (or denatured) form. Let ΔrH(std) =+347 kJ mol-1 and ΔrS(std) =-1010 J K-1 mol-1 for the equilibrium (F U) at 25℃. (a) Calculate the concentration of protein in each form if the total ...
*November 10, 2010 by KC*

**Chemistry**

need to calculate percent yield of MgNH4PO4 . 6H2O obtained in my experiment using 10-52-10 plant food label as a guide to determine the theoretical yield of MgNH4PO4 . 6H2O. My calculations so far: air dry weight of MgNH4PO4 . 6H2O = 2.30 g Grams of phosphorusin MgNH4PO4 ...
*May 27, 2011 by Julia*

**physics**

a jet pilot takes his aircraft in a vertical loop. a) if the jet is moving at a speed of 2000 km/h at the lowest point of the loop, determine the minimum radius of the circle so that the centripetal acceleration at the lowest point does not exceed 6.0g's b) calculate also the ...
*October 4, 2009 by jeffery*

**Chemistry**

I am beyond desperate. I do not understand how to calculate heat change at all and I have been looking online and reading my book for the last three hours. Below is posted a problem. It would be amazing if someone could work through it and explain each step they are doing and ...
*April 7, 2009 by Kathryn*

**AP Chemistry**

(a)calculate the mass percent of carbon in the hydrated form of the solid that has the formula BeC2O4 X 3 H2O (s). I divided 24.02 g by 151.08 g and got .16, or 16%. is that correct? Also, I'm having trouble with this follow up question. When heated to 220 degrees C, BeC2O4 X ...
*September 19, 2007 by Patrick*

**Business Finance - Check/Help**

Smith Manufacturing is considering the sale of two non depreciable assets, A and B. Asset A was purchased for $2000 and will be sold today for $2250. Asset B was purchased for $30,000 and will be sold today for $35000. The firm is subject to a 40% tax rate on capital gains. 1...
*September 11, 2011 by Sam*

**SCIENCE: GR.10 OPTICS CONVEX MIRRORS**

A convex security mirror has a focal length of -0.25m. A person with a height of 1.5m is 4m from the mirror. calculate the image distance and image height. AND An object 0.4m tall is placed 2.5m in front of a convex mirror that has a focal length of -90cm. Calculate image ...
*March 28, 2010 by lily*

**chemistry**

A sample containing 0.0500mol of Fe2(SO4)3 is dissolved in enough water to make 1.00L of solution. This solution contains hydrated SO4 2- and Fe(H2O)6 3+ ions. The latter behaves as an acid: Fe(H2O)6 3+ --> Fe(H2O)5OH 2+ + H+ a) Calculate the expected osmotic pressure of ...
*February 16, 2011 by Chris*

**Physics**

please can u check my answer Here are the questions: 1. A 0.45 kg book is resting on a dessktop 0.64 m high. Calculate the book's potential energy relative to a)the desktop? b)the floor. 2. A 0.636 kg basketball has a potential energy of 19J at teh basket. How high is teh ball...
*April 9, 2011 by Anonymous*

**Chemistry**

Hi, if anyone can give me help for any part of the question that would be great! I know how to draw the cell diagram, but am not sure what the half-reactions would be.... Here is the question: Give the cell diagram notation of the electrochemical cell that could be used to ...
*December 12, 2007 by Anne*

**Physic**

Two boxes sit side-by-side on a smooth horizontal surface. The lighter box has a mass of 5.91 kg, the heavier box has a mass of 7.67 kg. Calculate the contact force between these boxes when a horizontal force of 5.09 N is applied to the light box. and Calculate the contact ...
*September 22, 2009 by Timothy Tran*

**Chemistry**

Suppose that 30.0 mL of 0.20 M C6H5COOH(aq) is titrated with 0.30 M KOH(aq). (a) What is the initial pH of the 0.20 M C6H5COOH(aq)? (b) What is the pH after the addition of 15.0 mL of 0.30 M KOH(aq)? (c) What volume of 0.30 M KOH(aq) is required to reach halfway to the ...
*November 3, 2010 by Alania*

**physics**

A)Two boxes sit side-by-side on a smooth horizontal surface. The lighter box has a mass of 5.60 kg, the heavier box has a mass of 7.65 kg. Calculate the contact force between these boxes when a horizontal force of 4.83 N is applied to the light box. B)Calculate the contact ...
*February 12, 2014 by Sarah*

**physics**

water flows along a horizontal pipe of cross-sectional area 48cm^2 which has a constriction of cross-sectional area 12cm^2 at one place. If the speed of the water at the constriction is 4 m/s, calculate the speed in the wider section. The pressure in the wider section is 1.0 x...
*March 26, 2010 by Edwin*

**physics**

water flows along a horizontal pipe of cross-sectional area 48cm^2 which has a constriction of cross-sectional area 12cm^2 at one place. If the speed of the water at the constriction is 4 m/s, calculate the speed in the wider section. The pressure in the wider section is 1.0 x...
*March 26, 2010 by Edwin*

**chemistry**

a fire extignuisher produces carbon dioxide by the reaction between sodium hydrocarbonate and sulfuric acid. if a fire extinguisher is desgined to hold 600.0g of sodium hydrocarbonate calculate : the mass of sulfuric acid required to react with sodium hydrocarbonate AND ...
*April 17, 2010 by sarah *

**Physics**

Calculate the maximum deceleration of a car that is heading down a 30.0° slope (one that makes an angle of 30° with the horizontal) under the following road conditions. You may assume that the weight of the car is evenly distributed on all four tires and that the coefficient ...
*June 3, 2014 by Anonymous*

**Physics**

Calculate the maximum deceleration of a car that is heading down a 30.0° slope (one that makes an angle of 30° with the horizontal) under the following road conditions. You may assume that the weight of the car is evenly distributed on all four tires and that the coefficient ...
*June 3, 2014 by Anonymous*

**physics help me bob!**

A rock is thrown from the roof of a building with a velocity v0 at an angle α0. The height of the building is h. (i)Calculate the horizontal distance traveled by the projectile before it strikes the ground. (ii)Show that the speed of the rock just before it strikes the ...
*December 2, 2012 by dt*

**CHEMISTRY PLEASE HELP**

Using the data collected for part c on your data sheet and assuming the density of the vinegar is 1.00g/mL, 1) calculate the molar concentration of acetic acid (CH3COOH) in the vinegar sample using the average volume of NaOH. 2) calculate the mass percent of acetic acid in the...
*October 24, 2011 by Josh*

**Molar heat of combustion question!**

Calculate the molar heat of combustion of paraffin, expressed in units of kJ/mol. First calculate the thermal energy released when one mole of parafin burns) because one mole of parafin (c25h52) has a mass of 325g, the molar heat of combustion will be 352 times greater than ...
*February 5, 2013 by Allyson*

**Acids and Bases**

NaOH was added to 1.0 L of HI(aq) 0.40 M. Calculate H3O in the solution after the addition of .14 mol of NaOH. Calculate H3O in the solution after the addition of 0.91 mol of NaOH.
*March 23, 2011 by Kaitlyn*

**Statistics**

2. A researcher wants to find out how students feel about a proposal to ban smoking on campus. She selected THREE groups of “students who currently smoke”, “students who formerly smoke”, and “students who never smoke”. Also, she selects a sample of 5 students from each group ...
*October 14, 2013 by Chris*

**macroeconomics**

Assume that the government purchases decrease by 10 billion, with other factors held constant including the price level. Calculate the change in the level of real GDP demanded for each of the following values of the MPC. Then calculate the change if the government, instead of ...
*July 15, 2009 by jo*

**computing**

if you can answer these question and give the calculation that would be a great help thank you 1. Calculate the amount of storage required for a black and white bit-mapped graphic which has a resolution of 2000 x 1400 dpi. 2. calculate the amount of storage required for a 600 ...
*September 6, 2010 by LiiNa*

**Chemistry**

Using the data collected for part c on your data sheet and assuming the density of the vinegar is 1.00g/mL, 1) calculate the molar concentration of acetic acid (CH3COOH) in the vinegar sample using the average volume of NaOH. 2) calculate the mass percent of acetic acid in the...
*October 24, 2011 by Josh*

**Physics**

Example: A plane of wingspan 30m flies through a vertical field of strength 5 x 10-4T. Calculate the emf induced across wing tips if its velocity = 150ms-1. Answer: Calculate the area swept out each second by the wings. Multiply that by the field strength, B and you have got ...
*June 2, 2008 by Meesh*

**Biochemistry**

Acetylcholinesterase catalyzes the hydrolysis of the neurotransmitter acetylcholine: Acetylcholine + H2O actetate + choline The KM of acetylcholinesterase for its substrate acetylcholine is 9 x 10-5 M. In a reaction mixture containing 5 nanomoles/ml of ...
*September 22, 2012 by Robert*

**Chem help!!**

A rock salt (NaCl), ice, and water mixutre is used to make homemade ice cream. How many grams of rock salt must be added to lower the freezing point 10.0 degrees C? I have no idea what to do, please help! delta T = Kf*i*m delta T = 10. Kf is the molal freezing point constant, ...
*May 3, 2007 by Lindsay*

**business**

For this assignment you are to imagine that you are part of a select marketing group. This select group has been asked to consider the Colorado City Convention and Visitors Bureau survey of 25 hotels in the local area. The survey is concerned with the current availability of ...
*August 2, 2010 by ron *

**physics**

In a given electromagnetic plane wave the maximumelectric field strength is 400 V/m. What is the maximum magnetic field strength? How does the energy stored in the magnetic field compare with the energy stored in the electric field at any given time? how do you calculate the ...
*December 9, 2008 by al*

**Algebra**

Compare the future amounts (A) you would have if the money were invested at simple interest and if it were invested with annual compounding. $3,000 at 11% for 20 years (a) Calculate the future amount if the money were invested at simple interest. $ (b) Calculate the future ...
*May 28, 2012 by shirley*

**Algebra**

Compare the future amounts (A) you would have if the money were invested at simple interest and if it were invested with annual compounding. $4,000 at 12% for 30 years (a) Calculate the future amount if the money were invested at simple interest. (b) Calculate the future ...
*August 28, 2012 by Sue Jackson*

**chemistry**

- What fraction of an E coli cell is occupied by its DNA? How would I find the fraction? If I knew the volume of an E coli cell, would I divide that by the volume of DNA in an E coli cell? - A human cell is typically spherical with a diameter of 20 micrometers. Calculate the ...
*September 7, 2009 by Janae*

**chemistry**

given 2C6H6+15O2->12CO2+6H2O 1. Starting with a confined volume of 4.80L and O2 with a partial pressure of 223.1 torr at 25 degrees C. C6H6 is in excess. The reaction is allowed to proceed to completion. The container is returned to 25C. Both liquid water and benzene are ...
*November 13, 2012 by stacy*

**chemistry**

given 2C6H6+15O2->12CO2+6H2O 1. Starting with a confined volume of 4.80L and O2 with a partial pressure of 223.1 torr at 25 degrees C. C6H6 is in excess. The reaction is allowed to proceed to completion. The container is returned to 25C. Both liquid water and benzene are ...
*November 13, 2012 by stacy*

**Math**

option 1: 2-by-3, 3-by-4, and 4-by-5 option 2: 2-by-2 , 3-by-3 ,and 4-by-4 option 3: 3-by-5 , 3-by-6 , and 3-by-7 For each pyramid option, calculate the total number of shoeboxes used after each row has been completed. That is calculate the total number of shoeboxes in the top...
*October 15, 2013 by Pie*

**compemtary math**

. To determine the compound amount of an investment of $10,000 with an interest rate of 6% compounded monthly after 4 years requires you to use a table factor that goes beyond the Compound Interest Table. Calculate the new table factor for this investment. Now, using the new ...
*October 3, 2013 by mary*

**Finance**

calculate of EPS and retained earning: year ended2009 with a net profit before taxes of $218000. the company is subject to a 40% tax rate and must pay $32000 in preferred stock dividend before distributing any earning on the 85000 share of common stock currently outstanding. 1...
*May 31, 2011 by sweety*

**AP CHEM!**

IM SO CONFUSED PLEASE HELP! H2 +CO2-->H2O + CO When H2 is mixed with CO2 at 2,000K, equilibrium is achieved according to the equation above. In one experiment, the following equilibrium concentrations were measured. [H2]= 0.20mol/L [CO2]= 0.30mol/L [H2O]=[CO]= 0.55mol/L a/ ...
*April 3, 2007 by linds*

**Chemistry- partial pressures**

A sample of gas collected over water at 42 degrees C occupies a volume of one liter. The wet gas has a pressure of .986 atm. The gas is dried and the dry gas occupies 1.04 L with a pressure of 1.00 atm at 90 degrees C. Using this information, calculate the vapor pressure of ...
*January 1, 2007 by Dave*

**chemistry**

a drop of oil (volume 0.05cm3) is released from a medicine dropper on to the calm surface of a pond where it spreads out to cover an area of 40cm2. Assume that the oil film has a uniform thickness equal to the diameter of an oil molecule. CALCULATE the diameter of an oil ...
*March 7, 2007 by Pedro*

**Chemistry**

Consider a mixture of the two solids BaCl2.2H2O (FM 244.26) and KCl (FM 74.551). When the mixture is heated to 160C for 1 hour, the water of crystallization is drive off: BaCl2.2H2O --> BaCl2(s) + 2H2O(g) A sample originally weighing 1.7839g weighed 1.5623g after heating. ...
*September 28, 2011 by Asuna*

**Chemistry**

Calculate the standard entropy, ΔS°rxn, of the following reaction at 25.0 °C using the data in this table. The standard enthalpy of the reaction, ΔH°rxn, is –44.2 kJ·mol–1. C2H4(G)+H20 ---> C5H5OH ΔS°rxn= ______ J*K^-1*mol^-1 Then, calculate the standard ...
*November 30, 2014 by Patrick Panasko *

**Physics**

An open-topped tank completely filled with water has a release valve near its bottom. The valve is 1.75m below the water surface. Water is released from the valve to power a turbine, which generates electricity. The area of the top of the tank, AT, is 11.5 times the cross-...
*September 3, 2014 by Santi*

**math**

2.Calculate the growth rate of Asset J dividends, we have to assume that future dividend payments will grow at a constant rate into the future forever. This constant rate can be estimated by calculating the average growth rate from the past dividends. Calculate Asset J’s ...
*September 13, 2014 by Anonymous*

**Chemistry**

The equilibrium constant Kc for the following reaction is equal to 0.20 at 250°C. Calculate the equilibrium constant Kp for the reverse reaction at the same temperature. COCl2 (g) = CO (g) + Cl2 (g) I'm sorry.. English is a second language for me. After solving for K'c and ...
*March 15, 2012 by David*

**Science**

C6H5NH2 + H2O C6H5NH3+ + OH- 1. Aniline, a weak base, reacts with water according to the rxn above. a. A sample of aniline is dissolved in water to produce 25.0 ml of a .10 M soln. The pH of soln is 8.82. What is Kb for this rxn? b. The soln in part b, is titrated with...
*April 12, 2008 by Francis*

**chemistry**

H2 + I2 -> 2Hl 1.2 mol of hydrogen gas reacts with 1.0 mol of iodine vapour, after 5 minutes 0.6 mol of iodine remained. A) calculate the number of moles of hydrogen that have not reacted after 5 minutes. B) calculate the number of moles of hydrogen iodide that have been ...
*December 12, 2012 by fiona*

**physics, help urgent!**

charge Q = +4.5 ƒÝC is located at the origin and is fixed so that it cannot move. A small object with mass m = 2.0 g and charge q = +8.0 ƒÝC is released from rest at point A on the x-axis at x = 2.0 cm. The small object moves without friction along the x-axis under the ...
*November 14, 2012 by Brette*

**Physics. Please please help!**

A charge Q = +4.5 uC is located at the origin and is fixed so that it cannot move. A small object with mass m = 2.0 g and charge q = +8.0 uC is released from rest at point A on the x-axis at x = 2.0 cm. The small object moves without friction along the x-axis under the ...
*November 14, 2012 by Kyle*

**Animal Physiology-Membrane Potential**

Intracellular Extracellular Na+ 12 mM 160 mM Cl- 7 mM 110 mM K+ 140 mM 5 mM 1.How do you calculate the equilibrium potential for potassium, K+, under these conditions? 2. Assuming that Na+ is the only ion the plasma membrane of this cell is permeable to, at what voltage will ...
*September 15, 2011 by John*

**chemistry**

N2(g) + 3 F2(g) → 2 NF3(g) ΔH° = –264 kJ/mol ΔS° = –278 J/(mol∙K) a. calculate the maximum amount of non-PΔV work that can be accomplished through this reaction at a temperature of 500°C. b. Determine the temperature at which the equilibrium constant...
*April 22, 2012 by chamy*

**Chemistry**

If 3.21 g of BeC2O4 * 3H2O is heated to 220 C calculate the volume of the H2O(g) released, measured at 220 C and 735 mm Hg? please help me Convert g BeC2O4*3H2O to mols BeC2O4*3H2O. Convert mols BeC2O4*3H2O to mols H2O. Use PV = nRT to calculate volume of H2O. Post your work ...
*April 8, 2007 by Karisa*

**Chemistry lab**

1) Using the 1st equivalence point from part a calculate the molarity of the phosphoric acid. Molarity of NaOH = .1523 M Volume of phosphoric acid used 10.0mL Volume at equivalence point 7.410 mL and 14.861 mL 2) Using the 2nd equivalence point from part a, calculate the ...
*April 11, 2012 by Maura*

**Calculus**

Hello, I have some calculus homework that I can't seem to get started..at least not on the right track? I have 3 questions 1. integral of [(p^5)*(lnp)dp] I'm using the uv-integral v du formula So first, I'm finding u and I think it's lnp.......so du is 1/p Then, I think dv = p...
*January 23, 2007 by Shelley*

**CHEMISTRY**

I put down all the info that I found but I cant figure out the questions 1 & 2 at the bottom!! Empty Calorimeter- 11.6 g Room temp - 21 degrees celcius Three different experiments of 50mL 1(M) HCl reacts with 0.15 g Mg, 0.25g Mg, and 0.35g Mg respectively. The maximum ...
*November 8, 2010 by Anonymous*

**Chem**

if 50 mL of .012M barium chloride are mixed with 25 mL of 1.0 x 10^-6M sulfuric acid, will a precipitate form? Calculate Qsp. Compare with Ksp. I never learned what Qsp is, what do I do? Qsp = (Ba^+2)(SO4^-2) [That's Ksp, also; however, Ksp is at equilibrium and has a constant...
*May 7, 2007 by Anonymous*

**Chemistry - Science (Dr. Bob222)**

Posted by Ana on Saturday, May 3, 2014 at 11:23am. A zinc-copper battery is constructed as follows (standard reduction potentials given below): Zn | Zn2+ (0.10 M) || Cu2+ (2.50 M) | Cu Zn2+ + 2 e- → Zn(s) Eº = -0.76 V Cu2+ + 2 e- → Cu(s) Eº = 0.34 V The mass of ...
*May 5, 2014 by Ana *

**Astronomy**

Basically the ``Bohr radius'' for the dark matter is rB=ℏ^2 / GN M m^2 where m is the dark matter mass, M is the total amount of dark matter mass contained inside the ``gravitational atom'', and ℏ and GN are constants as usual. Taking the dark matter to be of ...
*October 1, 2013 by qwerty*

**Physics Grade 11**

I need Help answering this question what equations do i use from Newton's Law and how to solve it. I Have a test on Wednesday and im lost please help.!!! A piano is to be slid across the floor.IT had a mass of 450 kg. A) Calculate the normal force supporting the piano. B)If ...
*November 8, 2010 by Hena*

**finance, please help**

1. Calculate the present value of an investment given the following information: (a) Years—20, (b) Rate—10%, and (c) Future Value—$20,000. 2. Calculate the future value of an investment given the following information: (a) Years—10, (b) Rate—5%, and (c) Present Value—$10,000. ...
*June 3, 2012 by farah*

**Trigonometry**

When viewing Angel Falls (the world's highest waterfall) from Observation Platform A, located on the same level as the bottom of the waterfall, we calculate the angle of elevation to the top of the waterfall to be 69.30°. From Observation Platform B, which is located on the ...
*June 16, 2012 by Tim*

**Trigonometry**

When viewing Angel Falls (the world's highest waterfall) from Observation Platform A, located on the same level as the bottom of the waterfall, we calculate the angle of elevation to the top of the waterfall to be 69.30°. From Observation Platform B, which is located on the ...
*June 16, 2012 by Anonymous*

**business Math**

Carl Sonntag wanted to compare what proceeds he would receive with a simple interest note versus a simple discount note. Both had the same terms: $19,500 at 8% for 2 years. Use ordinary interest as needed. a. Calculate the simple interest note proceeds. Can someone help me? ...
*April 7, 2014 by marie*

**Chemistry**

Calculate [H3O+] in the following aqueous solution at 25 ∘C: [OH−]= 1.9×10−9M Calculate [H3O+] in the following aqueous solution at 25 ∘C: [OH−]= 2.1×10−2M Calculate [H3O+] in the following aqueous solution at 25 ∘C: [OH−]= 6.1×...
*April 29, 2014 by Brandon*

**volume:ration**

A worm has a diameter of 2.4cm and its length is upto 1.9M. a)How do I calculate the surface area? b)How do I calculate the volume? c)How do I work out the volume ratio of the worm? Please help! Thanx kim xxx Surface area= PI*2*radius * length] Volume= PI * radius^2 * length ...
*November 17, 2006 by Kim*

**math --- can someone help me pls?**

can anyone help me with these 2 questions pls? Calculate the slant height for the given cone. Round to the nearest tenth. (1 point) Diameter = 8 Height = 9 10.2 cm 11.4 cm 9.8 cm 12.0 cm Calculate the length of the diagonal for the given rectangular prism. Round to the nearest...
*February 26, 2014 by TTR+S<3 *

**physics college**

An antelope moving with constant acceleration covers the distance between two points 70.0 m apart in 7.00 s. Its speed as it passes the second point is 15.0 m/s. (a) What is its speed at the first point? (b) What is its acceleration? A car is stopped at a traffic light. It ...
*October 8, 2010 by meera*

**Chemistry**

The standard enthalpies of formation of ions in aqueous solutions are obtained by arbitrarily assigning a value of zero to H ions;that is, delta H(f) [H+(aq)]=0 A.for this reaction: calculate delta H(f) for the Cl- ions. HCl(g) ==H2O==>H+(aq)+Cl-(aq) delta H= -74.9 kJ/mol (...
*October 31, 2010 by Kristin*

**chem help w/ Lab**

Weight of the mustard package Sample: 3.02 (g) Weight of the mustard package Solution: 33.3 (g) Trial #1 Trial #2 Trial #3 Weight of Mustard Package Solution Delivered (g) : 1.09 .948 .909 Weight of NaOH Solution Delivered (g) : .354 .304 .269 Concentration of NaOH : 7.48e-3 (...
*October 17, 2012 by Den*

**Biology**

Zucchini cores placed in sucrose solutions at 27oC resulted in the following percent changes after 24 hours: % change in mass [Sucrose] 20 distilled water 10 0.2 M -3 0.4 M -17 0.6 M -25 0.8 M -30 1.0 M Graph the results and find the molar concentration of solutes within the ...
*October 11, 2007 by Harry*

**science(chem)**

I did a dehydration rxn with 1.424g of 4-methylcyclohexanol with .40ml 85% H3PO4 and 6 drops of concentrated H2SO4. I have to calculate the limiting reagent even though I do suspect it to be the 4-methylcyclohexanol. I do know the ratio is 1mol H3PO4: 3mol 4-methylcyclohexanol...
*December 2, 2007 by ~christina~*

**Chemistry DrBob**

I don't understand how you get the answer. I really don't understand any of this, how do I set it up with the numbers? once i get how to do this, then i feel i will understand how to set these up from here on out. so if you could, show all your work, thanks (A). A reaction ...
*April 27, 2011 by Ben*

**Chemistry- college**

The standard enthalpies of formation of ions in aqueous solutions are obtained by arbitrarily assigning a value of zero to H ions;that is, delta H(f) [H+(aq)]=0 A.for this reaction: calculate delta H(f) for the Cl- ions. HCl(g) ==H2O==>H+(aq)+Cl-(aq) delta H= -74.9 kJ/mol (...
*November 1, 2010 by Willy*

**stats**

The following data were collected from a case-control study of breast cancer and fat intake: case control High-fat diet 10 5 Low-fat diet 40 55 50 60 Statistical inferences for odds ratios are based on the natural log of the odds ratio, rather than the odds ratio itself (...
*July 16, 2013 by thane*

**Algebra **

The cost, in millions, to remove x% of pollution in a pond is modeled by the equation: . What is the cost to remove 75% of the pollution? Hint: Plug in and calculate, do not convert to a decimal. what value of x would make the equation undefined? Hint: Think about what makes ...
*December 13, 2011 by Chelsea*

**Chemistry**

Two Flasks containing the same inert gas are at the same temperature and pressure of 800 mmHg. One flask has volume of 1.0 L and the other, a volume of 2.0 L. Enough volatile liquid is injected into each of the flasks to allow phase equilibrium to be established. No leakage ...
*January 31, 2007 by Jason*

**Chemistry**

An empty flask weighs 128.632g. After vaporization of a sample of volatile liquid, at a measured temperature of 99.8 C. The flask is sealed, cooled to room temperature, and weighed. The mass is now 129.225g. The measured P atm is 757.7 torr. The flask is rinsed and filled ...
*July 13, 2008 by Anonymous*

**Chemistry**

An empty flask weighs 128.632g. After vaporization of a sample of volatile liquid, at a measured temperature of 99.8 C. The flask is sealed, cooled to room temperature, and weighed. The mass is now 129.225g. The measured P atm is 757.7 torr. The flask is rinsed and filled ...
*April 6, 2011 by Shannon*

**Physics **

A 21.1 g ball of clay is thrown horizontally at + 38.7 m/s toward a 1.2 kg block sitting at rest on a frictionless surface. The clay hits and sticks to the block. A. What is the speed of the block and clay right after the collision? m/s B. Use the block's initial and final ...
*November 7, 2012 by Courtney *

**physics**

please help i cannot figure this out A 0.27 kg ball of dough is thrown straight up into the air with an initial velocity of 12 m/s. Find the momentum of the ball of dough halfway to its maximum height on the way up. and A 61 kg pole-vaulter falls from rest from a height of 6.6...
*March 21, 2011 by luke*

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