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December 19, 2014

Search: Calculate the enthalpy for

Number of results: 19,321

Chemistry
Neat pure ethanol C2H5OH has an enthalpy of vaporization of 39.3 Kj/mol, and a vapor pressure of 0.308 atm at 50 C. What is the boiling point, at atmospheric pressure of 1 atm, of a solution consisting of 35 G of phenol (a non-electrolyte hydrocarbon with a molecular formula ...
April 30, 2012 by Mima

chemistry
The enthalpy change for the reaction below at 25oC is -2,252 kJ (per mole of C11H24). What is the internal energy change for the reaction at 25oC? 11 CO(g) + 23 H2(g) --> C11H24(l) + 11 H2O(l)
November 3, 2014 by Sasha

Chemistry
The vapor pressure of the liquid HF is measured at different temperatures. The following vapor pressure data are obtained. Temperature(K) Pressure mmHg 250 129.63 260 206.65 270 318.22 280 475.16 Determine the enthalpy of vaporization. I have know idea how to start this. Thank...
February 7, 2012 by Hannah

Chemistry
A 5.0g KBr sample, at 25 degrees celsius, dissolved in 25 ml of water, also at 25 degrees celsius. the final equilibrium temperature of the resulting solution is 18.1 degrees celsius, What is the enthalpy change in J/g and KJ/mole of KBr.
November 14, 2012 by jonathan

Chemistry - General, Hess's Law
In an experiment, 11.6g of a salt was dissolved in 100.0ml of water contained in the above calorimeter, all at an initial tmperature of 24.5 degrees Celsius. After dissolution was complete, the temperatur was 31.8C. The specific heat of the solution is 3.63J/gxC and the ...
July 24, 2009 by Sahar

Chemistry
A 5.0-g Sample of KBr at 25.0 degrees celsius dissolves 25.0 mL of water also at 25.0 degrees celsius. The final equilibrium temperature of the resulting soltution is 18.1 degrees celsius. What is the enthalpy of of solution in kilojoules per mole of KBr?
March 20, 2013 by Sam

Chem 2 enthalpy
How much heat is evolved when 25.5 g of benzene freezes at 5.5 Celcius (molar heat of fusion is 9.94 kJ/mol and molar mass of benzene= 78.0 g/mol)
August 26, 2010 by Anonymous

Chemistry
The net reaction for fusion on a star like our Sun is: 4H(1,1) ==> He(4,2) + 2e(0,+1) Calculate the mass defect for this reaction. If one atom of He is formed this way, calculate the energy released. If one Kg of He is formed, calculate the energy released. The masses of ...
March 16, 2014 by Jay

Thermochemistry
When 1.477 mole of an inorganic salt were dissolved in 1.00 L of water in a constant pressure solution calorimeter, the temperature of the calorimeter changed from 25.00oC to 24.40 oC. The total heat capacity of the calorimeter including all its contents was 2.18 kJ oC-1 What ...
June 12, 2009 by Douglas

science-chemistry
please anwser soon, a rigid 4.10L flask contains a mixture of 1.25 moles of H2, 0.250 mole of O2, and sufficient Ar so that the partial pressure of Ar in the flask is 1.00 atm. The temperature is 63.5 degrees C A) Calculate the total pressure in the flask B) calculate the mole...
April 29, 2012 by Bryan

apchem
A 15.0g sample of liquid ethanol, C2H5OH, absorbs 5.13x10^3 J of heat at its normal boiling point, 78.0C. The molar enthalpy of vaporization of ethanol is 39.3kJ/mol. (a) What volume of ethanol vapor is produced? The voume is measured at 78.0C and 1.00atm pressure. (b) What ...
January 27, 2008 by alk

Chemistry
A 15.0g sample of liquid ethanol, C2H5OH, absorbs 5.13x10^3 J of heat at its normal boiling point, 78.0C. The molar enthalpy of vaporization of ethanol is 39.3kJ/mol. (a) What volume of ethanol vapor is produced? The voume is measured at 78.0C and 1.00atm pressure. (b) What ...
January 27, 2008 by David

chemistry - quant.
I need help calculating the pH of a solution that is .0400M Na3AsO4 I was trying to calculate the pH with [H30+]=sqrt(ka1*ka2) What is the correct way to calculate this? Thankyou
December 13, 2007 by anon

physics
A 5.40 Kg package slides 1.47 meters down a long ramp that is inclined at 11.6 degress below the horizontal. The coefficient of kinetic friction between the package and the ramp is = 0.313. Calculate the work done on the package by friction. Calculate the work done on the ...
December 3, 2012 by clariza gonzalez

Inorganic chemistry
The thermochemical equation for the combustion of hexane is shown below. C6H14(g) + 19/2Os(g) ==> 6CO2(g) + 7H2O(g) Delta H = -4163kJ What is the enthalpy change for the combustion of 2.50g C6H14? 2.50 g/86g = .029 mol -4163kJ/.029 = -1.43 x 10^5kJ
May 12, 2009 by Steve

Math
Julie is conducting an experiment where she placed 29.5 mL of water in a calorimeter at 15.0 C. Then, 2.4 g of A (molar mass = 48.0 g/mol), also at 15.0C, is added to the water in the calorimeter and the temperature of the solution increases to 28.0 C. The following ...
October 5, 2014 by Kelly

Physics
A motorboat is traveling 5m/s East, and encounters a current traveling 2.5m/s, North. If the witdth of the river is 80m wide, how much time does it take the boat to reach the other shore. I understand how to calculate the resulatant velocity, but I dont understand why you use ...
October 20, 2010 by Jennifer

Science
Write the formula, substitute numbers and units(labels)Mike mixed 20g of 60C water with 40g of 25C water. The final temperature was 39C. 1.Calculate the change of temperature for hot water. 2.Calculate the calories transferred from the hot water. 3.Calculate the amount of heat...
March 29, 2010 by Jamie

Chemistry
Explain why the absolute values of the standard enthalpy change in the reaction and heat measured by the calorimeter are not equal. Assume that there are no measurement errors of any kind. In the previous problem I solved that Delta H rxn was -1500 and q = 1.519 x 10^6 J and I...
March 17, 2012 by David

Chemistry LAB 1
What is the Molar Enthalpy of Neutralization in kJ/mol if 5.00 moles of HCl(aq) (acid) neutralized 5.00 moles of NaOH(aq) (base) and released 6649J of heat? *Make sure you report your answer using the correct sign* DrBob222 gave me some help and I worked it out and got 1329.8 ...
November 6, 2013 by BRANDIE

Chemistry -please help!
A zinc-copper battery is constructed as follows at 25C. Zn|Zn^2+ (0.15 M)||Cu2+(3.00 M)|Cu The mass of each electrode is 200. g. a) Calculate the cell potential when this battery is first connected. - i got this to be 1.14V b.) Calculate the cell potential after 10.0 A of ...
April 28, 2011 by Mandy

Chem
(a) The molar solubility of Ag2CrO4(s) at 35C is 1.3 10-4 mol/L. Calculate Ksp. (b) If 0.0490 g of AgIO3 dissolves per liter of solution, calculate the solubility-product constant. (c) Using the appropriate Ksp value from Appendix D, calculate the solubility of Cu(OH)2 in ...
April 27, 2011 by Rebekah

physics
A resistor (R = 900 ), a capacitor (C = 0.25 F), and an inductor (L = 2.0 H) are connected in series across a 240 Hz AC source for which Vmax = 140 V. Calculate values for the following. ---I only need help with part c---- c) the phase angle between the current and voltage ...
August 5, 2007 by asmi

phys
An airplane is heading due south at a speed of 590 km/h. If a wind begins blowing from the southwest at a speed of 65.0 km/h (average). Calculate magnitude of the plane's velocity, relative to the ground. Calculate direction of the plane's velocity, relative to the ground. ...
September 15, 2009 by physics

Chemistry
H2O(l) = H2O(g) deltaHvap = + 40.7kJ shows the change in enthalpy when 1mol of liquid water vaporizes into water vapor. This is called the molar heat of vaporization. Given this information which is the proper value for the molar heat of condensation?
April 5, 2010 by Tori

Chemistry
The phrase the heat absorbed or released by a system undergoing a physical or chemical change at constant pressure is a. the change in enthalpy of the system. b. the change in internal energy of the system. c. the definition of a state function. d. the temperature change of ...
July 2, 2013 by Jessica

molarity
calculate the molarity of k+ in a soln prepared by adding .2L of .200M K3PO4 and 75.0mL of .5M K3PO4. assume volumes are additive. A few of steps here and more than one way to answer the problem You need to calculate the total number of moles of K3PO4 from the two volumes and ...
April 5, 2007 by Christine

Chem
A gas is compressed from 73.7 L to 1.9 L at 0.70 atmospheres? In addition a total of 4400 J of heat are gained from warmer surroundings. What is the change in internal energy in kJ? I have a general idea of how to do this, but I tried and got -2851.8, which isn't right. What ...
October 19, 2012 by Anonymous

physics
A stone is projected upward at an angle of 60degree to the horizontal from the top of a tower of height 100meter and it hits the ground at a point. If the initial velocity of projection is 100meter. Calculate the maximum height of the stone above the ground. Calculate the time...
January 3, 2012 by John

physics
A stone is projected upward at an angle of 60degree to the horizontal from the top of a tower of height 100meter and it hits the ground at a point. If the initial velocity of projection is 100meter. Calculate the maximum height of the stone above the ground. Calculate the time...
January 3, 2012 by John

chem
The combustion of hydrogenoxygen mixtures is used to produce very high temperatures (approximately 2500 C) needed for certain types of welding operations. Consider the reaction to be H2(g) + 1/2O2(g) --> H20(l) Standard enthalpy is -241.8kj What is the quantity of heat ...
October 3, 2008 by tomi

chemistry
How do you calculate the theoretical cell voltage? 1) Zn|Zn^+2 (1M)| Cu|Cu^+2 (1M) 2) Cu|Cu^+2 (1M)| Zn|Zn^+2 (1M) 3) Fe|Fe^+2 (1M)| Cu|Cu^+2 (1M) 4) Zn|Zn^+2 (1M)| Cu|Cu^+2 (0.1M) 5) Cu|Cu^+2 (1M)| Cu|Cu^+2 (0.1 M) Now 4 and 5 have different moles how do you calculate those ...
July 19, 2012 by fenerbahce

chemistry
The enthalpy change for the solution process when solid sodium hydroxide dissolves in water is -44.4 kJ/mol. When a 13.6 g sample of NaOH dissolves in 250.0 g of water in a coffee-cup calorimeter, the temperature increases from 23.0 o C to __________ o C. Assume that the ...
November 15, 2010 by Anonymous

Math
An airplane is heading due south at a speed of 590km/h. If a wind begins blowing from the southwest at a speed of 65.0km/h (average). Calculate magnitude of the plane's velocity, relative to the ground. Calculate direction of the plane's velocity, relative to the ground. ...
September 12, 2009 by Anne

Chemistry
Caluclate the delta H for this reaction using standard enthalpies of formation. (The standard enthalpy of formation of liquid pentane is -146.8kJ/mol. Balanced equation balanced equation: C5H12(l)+8O2(g)-->5CO2+6H2O(g) CO2=393.5 H2O=40.7
December 4, 2010 by Ashley

thermodynamics
A scuba tank contains 1.5 kg. of air. The air in the tank is initially at 15 degree celcius. The tank is left near an engine exhaust line, and the tank's pressure doubles. Determine the final temperature, change of internal energy, change of enthalpy, and heat.
November 29, 2011 by hermie

Hudson
In a calorimetric experiment, 6.48 grams of lithium hydroxide was dissolved in water. The temp of the calorimeter rose from 25 celcius to 36.66 celcius. What is the molar change in enthalpy for this procces? LiOH(s) -> Li(aq) + OH (aq) (the heat capacity of the calorimeter ...
October 8, 2012 by k-dawg

chemistry
for a particular isomer C8H18, the following reaction produces 5113.3 kj of heat per mole of C8H18 consumed under standard conditions c8h18(g) + 25/2 O2 (g) ---> 8co2(g) + 9h2o(g) what is the standard enthalpy of formation of this isomer of c8h18? o2= 0 co2(g)= -393.5 h2o(g...
June 19, 2013 by Annie

chemistry
2. If the accepted enthalpy change value for the dissolving of sodium hydroxide in water is −44.2 kilojoules per mole, determine the percent error of the experimental value that you calculated in Part I. Show your work. (experimental - actual value) / actual value 100 %
July 18, 2013 by yuppp

Physics
A worker applies a constant force of magnitude F = 339 N on a crate in a direction = 26.1o above the horizontal as he pulls it across a level floor through a distance of s = 7.20 m. The mass of the crate is m = 53 kg and the coefficient of kinetic friction between the floor ...
December 18, 2012 by Sara H

Chemistry
I just did an experiment on the enthalpy of combustion of different alcohols, and for my report, I've written that the condition of the wick is a source of random error, but i can't seem to explain it. I've written that it affects the rate of burning of the flame, and the heat...
April 7, 2009 by TP

Chemistry
Dr.Bob, this is regarding to the enthalpy posts.... I don't understand why you just switch it to negative??How do you know that it is neg???? I thought it started out neg though the problem does not give the number.... I am sorry,but I am a very slow learner...thank you for ...
November 15, 2013 by Anonymous

chem
a buffer is made by adding 150 ml of .595M BaF2 and 0f .500M of HF solution. calculate the pH of this buffer system calculate the pH of this buffer after adding .100 mol Hcl calculate the pH of this buffer after adding .0750 mol Ca(OH)2 ka(HF)= 6.9x10^-4 kb(F-)= 1.4 x 10^-11
March 1, 2010 by simi

Chemistry
Lead has a melting point of 327C, its specific heat is J/gdeg, and its molar enthalpy of fusion is 4.80 kJ/mol. How much heat, in kilojoules, will be required to heat a 500.0-g sample of lead from 23.0C to its melting point and then melt it?
November 4, 2012 by steph

Chemistry
Lead has a melting point of 327C, its specific heat is J/gdeg, and its molar enthalpy of fusion is 4.80 kJ/mol. How much heat, in kilojoules, will be required to heat a 500.0-g sample of lead from 23.0C to its melting point and then melt it?
November 4, 2012 by steph

chemistry
The normal boiling point of ethanol is 78.5C. Using the following information: delta H formation (C2H5OH (g))= -234.38 kJ/mol determine the enthalpy of vaporization of ethanol. I know it should be around 39.3 according to a table in my textbook, however, I don't know how to ...
July 18, 2012 by Kellie

chemistry-lattice energy
Determine the lattice energy for CaBr2 if the enthalpy of solution for CaBr2 is -145 kJ/mol, and the heats of hydration for Ca2+ and Br- are -1650 kJ/mol and -292 kJ/mol respectively.
October 1, 2012 by Bru

Chemistry
A total of 2.00 mol of a compound is allowed to react in a foam coffee cup that contains 141 g of water. The reaction caused the temperature of the water to rise from 21.0 to 24.7 degrees Celsius. What is the enthalpy of this reaction? Assume that no heat is lost to the ...
October 11, 2010 by Karen

physics
A 5.20 package slides 1.57 down a long ramp that is inclined at 13.0 below the horizontal. The coefficient of kinetic friction between the package and the ramp is = 0.305 Calculate the work done on the package by friction. Calculate the work done on the package by gravity. ...
October 4, 2012 by Matt

physics
A 5.20 package slides 1.57 down a long ramp that is inclined at 13.0 below the horizontal. The coefficient of kinetic friction between the package and the ramp is = 0.305 Calculate the work done on the package by friction. Calculate the work done on the package by gravity. ...
October 5, 2012 by Matt

chem please help drbob222
What will be the result of a reaction if its enthalpy change is positive, its entropy change is negative and Gibbs free energy is positive? A. Spontaneous, if the temperature is high B. Nonspontaneous, if the temperature is low C. Always spontaneous D. Never spontaneous
November 26, 2014 by Morgan

Chemistry
I need help on how to calculate the following please: Calculate the risk assesment of the amount of the ozone in the air between the hours of 4pm and 6pm where I live(Corpus Christi,Texas)
August 27, 2011 by Jelly

Physics
NEED HELP On a flat battle ground, a catapult is used to launch a rock with a velocity of 25m/s at angle 30 degrees above the horizontal.? Sketch the situation and decompose the initial velocity vector. WHat are the initial values for Vx and Vy? Calculate the maximum height ...
August 19, 2014 by Jeesha

Physics
The following figure represents the ride for a cart with a mass of 200 kg along a frictionless track. a. Calculate the velocity of the cart at points A, B, and C if the cart is dropped from a height of 100m with a initial velocity of 10 m/s. b. Calculate the height of the ...
July 25, 2014 by Liz

Chemistry
Mass (before reaction): test tube + HCl(aq) + stir bar + capsule 26.600 g Mass (after reaction): test tube + HCl(aq) + stir bar + capsule 25.300 g Volume of water displaced from the squirt bottle 148 mL Temperature of the CO2(g) 287.4 K Pressure (atm) 1.032 atm Using this data...
October 21, 2012 by Karina

chemistry
A. Strong Base 1.) What is the concentration of a solution of KOH for which the pH is 11.89? 2.) What is the pH of a 0.011M solution of Ca(OH)2? B. Weak Acid 1.) The pH of a 0.060M weak monoprotic acid HA is 3.44. Calculate the Ka of the acid. 2.) The pH of 0.100M solution of ...
January 20, 2011 by jaycab

chemistry
Which of the following equations represents a reaction for which the delta H can be called a standard enthalpy of formation, delta Hf? a) FeO(s) + CO2(g) -> FeCO3(s) b) 1/2 N2(g) + 2 O(g) -> NO2(g) c) 2 Na(s) + Cl2(g) -> 2 NaCl(s) d) Ba(s) + N2(g) + 3 O2(g) -> Ba(...
January 23, 2012 by timmy

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 by John

Physics
A stone that starts at rest is in free fall for 8.0 s. a.Calculate the stone's velocity after 8.0 s. b. What is the stone's displacement during this time? Given: t = 8.0 s a = 9.81 m/s^2 For a, in order to calculate the velocity, should i use d = vit + 1/2 at^2 and only use ...
December 25, 2009 by Priscilla

Chemistry
Why wouldn't you do this reaction directly in a lab (and would rather use Hess' Law to determine the enthalpy of formation)?: 1/2N2(g) + 2H2(g)+ 1/2Cl2(g) -> NH4Cl(s) I don't think the reactants are that dangerous...? It's still pretty safe to do in a lab, isn't it? Are ...
February 18, 2013 by a Canadian

Maths
The distance from TDC (top dead centre) for the pin is given by x when the crank is at angle . Hence : i) Give an equation for x in terms of the other variables (r, L and ). ii) If the crank rod is rotating at a constant value of ω calculate the speed of ...
May 17, 2011 by Karl Haxell

math
The distance from TDC (top dead centre) for the pin is given by x when the crank is at angle . Hence : i) Give an equation for x in terms of the other variables (r, L and ). ii) If the crank rod is rotating at a constant value of ω calculate the speed of ...
May 17, 2011 by Karl Haxell

chemistry
the enthalpy of fusion of ice is 6.02 kJ/mol. the heat capacity of liquid water is 75.4 J/molC. What is the smallest number of ice cubes at 0 degrees C each containing one mole of water, necessary to cool 500g of liquid water initially at 20.0 degree C to 0.0 degree C
May 24, 2011 by el

Maths
In an orthonormal system, you're given the following: Point P(1,2) Lina a=cartesian eqn:4x-3y+6=0 Line b=parametric eqns:x=-5+3& y=-& (real n) Circle z=cartesian eqn:x+y-2x-3=0 (a)Calculate the angle between lines a an b (b)Calculate the coordinates of the point of ...
May 4, 2008 by Anonymous

Mathematics
In an orthonormal system, you're given the following: Point P(1,2) Lina a=cartesian eqn:4x-3y+6=0 Line b=parametric eqns:x=-5+3& y=-& (real n) Circle z=cartesian eqn:x+y-2x-3=0 (a)Calculate the angle between lines a an b (b)Calculate the coordinates of the point of ...
May 18, 2008 by Anonymous

Math
If a = 3i + 2j - k and b = -2i + j calculate each magnitude. a) a + b I got sqrt3, but the answer at the back of the book says sqrt11. 2) If D(3,4,5) and E(-2,1,5) are points in space calculate each expression and state what it represents. |OD| can you please do those and ...
March 29, 2008 by Anonymous

chemistry
1998 scientists using a special type of electron microscope were able to measure the force needed to break a single chemical bond. If 2.0 x 10^-9 N was needed to break a C-Si bond, estimate the bond enthalpy in kJ/mol. Assume that the bond had to be stretched by a distance of ...
September 26, 2011 by Amber

Chemistry
What is the enthalpy change (in kJ) for burning 49.0 g of methyl alcohol? I tried this question and got the wrong answer of 1047.74. A gas is compressed from 73.7 L to 1.9 L at 0.70 atmospheres? In addition a total of 4400 J of heat are gained from warmer surroundings. What is...
October 19, 2012 by Anonymous

college chemistry
Use the thermochemical equations shown below to determine the enthalpy (kJ) for the reaction: H2SO3(l)=>H2S(g) + 3/2O2(g) H2SO3(l)=>H2O(l) +SO2(g) DH=62KJ SO2(g)=>S(s) + O2(g) DH=297KJ H2S(g) + 1/2O2(g)=>S(s) + H2O(l) DH=-155KJ
October 24, 2010 by sara

Chemistry
A 5.0-g Sample of KBr at 25.0 degrees celsius dissolves in 25.0 degrees celsius 25.0 mL of water also at 25.0 degrees celsius. The final equilibrium temperature of the resulting soltution is 18.1 degrees celsius. What is the enthalpy of of solution in kilojoules per mole of KBr?
December 2, 2010 by Sally

Chemistry
The enthalpy of vaporization of chloroform (CHCl3) is 29.2 kJ mol-1 at its normal boiling point 61.2 Celsius. what is the standard change in entropy for vaporization of chloroform at its normal boiling point? Answer I got was 29.2/334.2 = 0.0873. (CORRECT?)
April 2, 2013 by Viv

chemistry
how in the world do you do this problem? Use the thermochemical equations shown below to determine the enthalpy (kJ) for the reaction: H2SO3(l)=>H2S(g) + 3/2O2(g) H2SO3(l)=>H2O(l) +SO2(g) DH=62KJ SO2(g)=>S(s) + O2(g) DH=297KJ H2S(g) +1/2O2(g)=>S(s) + H2O(l) DH=-...
October 24, 2010 by anonymous

chemistry - energy and change rev (help)
the below 2questions i could not answer while revising for this chapter pls help me out a little. 58. When a vehicle is parked in the sunlight on a hot summer day, the temperature inside can approach 55C. One company has patented a non-CFC propelled aerosol that can be ...
March 23, 2011 by Babelii

chemistry
calculate [h3o] in solutions. 0.040 of HCl and 0.080 HOCl. 2. calculate OH for the solutions of 0.0063 ba (OH)2 and 0.0110 of BaCl2
April 11, 2010 by anonymous

math
Consider the function defined below. y = 2t3 - 4t2 + 3 (a) Calculate the second derivative. y '' = (b) Calculate the third derivative. y ''' =
June 21, 2010 by Jack

Chemistry
Calculate how much heat 32.0 g of water absorbs when it is heated from 26.0C to 73.5C. In joules, and then we have to calculate calories too, how is that done? I was absent. Thanks so much!
May 25, 2011 by Jane

Chemistry
Calculate the wavelength of broadcast waves. Calculate the energy associated with the broadcast frequency for WPHT, 1210 kHz.
November 5, 2011 by Anonymous

math
calculate the mass (in SI units) of a 150ib human being? m= Calculate the weight ( in English units) of a 200kg rhino m=
January 26, 2012 by bree

chemistry
For a particular isomer of C8H18, the following reaction produces 5113.3 kJ of heat per mole of C8H18(g) consumed, under standard conditions. C8H18(g) + 25/2(O2)(g) -> 8CO2(g) + 9H2O(g) DeltaH= -5113.3 kJ What is the standard enthalpy of formation of this isomer of C8H18(g)?
January 29, 2012 by Mike

epidemiology
In a fictitious study, 100 out of 1000 people aged 60 years and over were positive in detecting breast cancer using Tumour Biopsy (gold standard). Using mammography, 90 of breast cancer patients and 135 healthy persons were also positive by this test. (I) Calculate and ...
August 18, 2012 by Ekrem

ap chem
A 9.00 M solution of a weak acid, HA, has a pH of 1.30 1.) calculate [A-] at equilibrium 2.) calculate [HA] at equilibrium Use pH to get (H^+). Ka = (H^+)(A^-)/(HA) (A^-) = (H^+). (HA) = 9 Plug and chug. Post your work if you get stuck.
March 22, 2007 by Jaron

Physics
A particle's initial velocity is given by vox = -1.0 m/s and voy = 3.0 m/s. Its acceleration is ax = 0.50 m/s^2 and ay = -0.90 m/s^2 (a) Calculate its velocity 2.0 s later. (b) Calculate its displacement at that time.
October 4, 2009 by Sandhu

statistics
GIVEN THE FOLLOWING STATISTICAL VARIABLES A:m(A)=5 B:m(B)=13 var(A)=25 Var(B)=6 1.calculate mean of Z= 4B-2A 2.Calculate the Standard Deviation assuming cov (A,B)=0
August 17, 2010 by RASHMI

physics
A force of 303.0 N is used to push a 160 kg mass 30.0 m horizontally in 3.00 s. (a) Calculate the work done on the mass. 1 kJ (b) Calculate the power developed. 2 kW
December 12, 2011 by Anonymous

chemistry
calculate r.m.s velocity of he molecule at 300k.also calculate the total k.e(in calories)of the molecules in one litre he at 300k & 1atm?
July 6, 2012 by dip

Math calculate depreciation
please explian how to calculate depreciation for federal income taxes what method do I use thanks :)
November 14, 2007 by Anonymous

calculus
calculate the indefinite integral 2sec^2x dx (cosx)/(sin^3x) dx calculate the definite integral interval pi/4, pi/12 csc2xcot2x dx
January 6, 2008 by anonymous

geometry
In the following figure given a circle C(o,3) Bp=AB and BA^N = 30 a) Calculate AP,BN and AN b)Calculate AQ and BQ c) Show That M is the mid point of (AP) d)Show that (OM)is perpendicular to (A)
April 16, 2010 by Nour

physics
A spherical conductor has a radius of 14.0 cm and charge of 26.0 C. Calculate the electric field and the electric potential (a) r = 10.0 cm, (b) r = 20.0 cm, and (c) r = 14.0 cm from the center. how do i calculate k?
February 7, 2012 by confused

Chemistry-Help
An AM radio station broadcasts at 1060 kHz. Calculate the wavelength of the corresponding radio waves. How do I calculate this?
April 30, 2012 by Liz

Physics
An electric dipole comprised of two charges Q and -Q are separated by a distance of 3.0 cm. Assume Q = 2.0x10^-6 C and -Q = -2.0x10^-6 C. Find the magnitude and direction of the electric field vector E and point P, which is 4.0 cm to the right of the center of -Q. Find the ...
March 13, 2012 by Michelle

Chemistry
When 23.6 of calcium chloirde CaCl2 was dissolved in water in a calorimeter, the temperature rose from 25.0 degrees C to 21.56 degrees C. If the heat capacity of the solution and the calorimeter is 1071 J/ degrees C, what is the enthalpy change when 1 mol of sodium nitrate ...
November 1, 2007 by Lauren

chemistry
When water freezes, the phase change that occurs is exothermic (DH = -6.02 kJ). Based on the change in enthalpy, you would expect that water would always freeze. Use the concepts of entropy and free energy to explain why this phase change is favourable only below o degrees ...
April 6, 2008 by Sarah

Chemistry
For ethanol, C2H5OH, which is mixed with gasoline to make the fuel gasohol, Hf = -277.63 kJ/mol. Based upon data in Table 6.2, and that the density of ethanol is 0.787 gcm-3, the number of kilojoules released by burning completely 2.40 gallons of ethanol is ? *Table 6.2 ...
October 16, 2011 by A

Thermodynamics
a rigid vessel of volume 1m(^3) contains steam at 20bar and 400 degrees Celcius. The vessel is cooled until the steam is just dry saturated. Calculate the mass of steam in the vessel, the final pressure of the steam and the heat rejected during the process. The answers should ...
March 12, 2010 by Claire

Please help with really hard chem question?
An electrolysis experiment was run for 17.5 minutes at an average current of 191 milliamps (mA). The mass lost by the copper anode was 0.0679 grams. a) Calculate the number of coloumbs transferred. (coloumb=ampsxsec) b) Calculate the moles of copper lost from the anode. c) ...
April 16, 2014 by Dianne

Physics
A 275 kg piano slides 4.0 m down a 30 incline and is kept from accelerating by a man who is pushing back on it parallel to the incline. The effective coefficient of kinetic friction is 0.40. a) Calculate the magnitude of the force exerted by the man. b) Calculate the work ...
December 11, 2013 by Josh

Physics
A 275 kg piano slides 4.0 m down a 30 incline and is kept from accelerating by a man who is pushing back on it parallel to the incline. The effective coefficient of kinetic friction is 0.40. a) Calculate the magnitude of the force exerted by the man. b) Calculate the work ...
December 11, 2013 by Josh

Chemistry
What is the entropy of CH3OH? My CRC tables list 239.865 J/K*mol @ 298.15o K. Do you also know the enthalpy? deltaHof= -201.000 kJ/mol according to the CRC Handbook,1995-96 edition.
March 26, 2007 by Meg

Accounting 7
Noteworthy, Inc., produces and sells small electronic keyboards. Assume that you have the following information about Noteworthys costs for the most recent month. Depreciation on factory equipment $800 Depreciation on CEO's company car $100 Speakers used in the keyboard $1,...
August 31, 2014 by Mia

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