Tuesday
July 29, 2014

Search: CHEMSITRY

Number of results: 72

chemsitry
how do you find PH of {H+} = 1.0 * 10 to the -5 power M?
May 13, 2012 by ryan

chemsitry
what is the frequency of a wavelength of 764 nm?
December 17, 2010 by zahra

Chemsitry
How do we improve the efficiency of Column Chromatography?
August 19, 2010 by Alan

chemsitry
calculate Delta H of RXN 2 N2 (g) + 3 H2( g) ->2 NH3 (g)
November 13, 2010 by Sarah

chemsitry
buffer calculate the ph of the .1m propanoic acid Ka 1.35e-5
April 10, 2011 by neee

chemsitry
the ph of a .030M C2H5 COOH solution is 3.20. What is this acids Ka?
May 12, 2012 by ryan

chemsitry
How many moles of \rm CaC_2O_4 are present in this kidney stone?
March 12, 2013 by indeus evans

Chemsitry
Calculate the weight of KHP that will react with 25mL of .1M NaOH
October 19, 2010 by Sierra

Chemsitry
What is the name of the following ion compund. SrO Cr1I2
October 23, 2010 by Anonymous

chemsitry
hydrogen burns in oxygen to for water.caculate the volume?
August 3, 2012 by sam

chemsitry
you start with 150.0g of pentane and 500.0L of O2. how many grams of H2O will you make?
March 29, 2013 by sonya

chemsitry
calculate the work done when 50.0 g of tin dissolves in excess acid at 1.00 atm and 25c
February 14, 2010 by Anonymous

chemsitry help again please
Write the formula of the conjugate base for acid HClO2 .
November 19, 2013 by chelsea

organis chemsitry
what is the main structural feature of the azo dyes that causes them to be colored compounds.
December 29, 2010 by ME

chemsitry
The molecular geometry of POCl3 is tetrahedral. What hybridization does this indicate for the central P atom? Why is the answer spy?
December 11, 2013 by Chelsea

11th grade chemsitry
If 150 g of water is heated from 3.0 celieus to 48.0 celieus how many joules of heat are needed
May 2, 2011 by Trent

Chemsitry 130
Can someone please help me with the=is problem... In each of the following, determine which reactant is being oxidized and which is being reduced: A. Al(s) + O2(g) -----> Al2O3(s) B. Ca(s) + F2(g) -----> CaF2(s) Thanks so much for the help ;-)
October 8, 2009 by Taylor

Chemsitry
I just took my Chemistry midterm, and would like to know how to calculate my grade on the midterm with the curve. MEAN = 8.9 STANDARD DEVIATION = 2.9 MY SCORE = 7 Thank You!
October 12, 2010 by Anonymous

Chemsitry
Use these data to estimate Avogadro's number. Palladium crystallizes with a face-centered cubic structure. It has a density of 12.0g/cm^3 , a radius of 138 pm , and a molar mass of 106.42 g/mol .
June 17, 2012 by Lauren

Chemsitry
For a particular redox reaction NO2 is oxidized to NO3 and Cu2 is reduced to Cu . Complete and balance the equation for this reaction in basic solution. Phases are optional.
April 1, 2013 by Connor

Chemsitry
What is the phase of a compound at 600 mmHg and 32oC if it melts at 35oC when pressure is 760 mmHg? Its triple point occurs at 200 mmHg and 36oC.
April 8, 2010 by Dan

chemsitry
How would you figure-out which one is greater. You have 2.0 moles of H2O and 1.0 moles ofCO2 how would you get the answer.
December 6, 2010 by sherry

chemsitry
Calculate the mass in grams of sodium bromide, NaBr, are needed to prepare 250.0 mL of a solution of sodium bromide that is 3.50% (m/v).
March 20, 2011 by allen

Chemsitry
Q1. How to find ions of a particular element.. Tell me the methods or procedure to do so? Q2. What are X-rays? Q3. What do u mean by "Irridated with X-rays? Q4. What do u mean by "radiation"?
August 14, 2009 by Akashdeep

chemsitry
complete the following sentence. For an experimental measurement, the experimental value minus the accepted value is called the _______. absolute error
January 12, 2007 by Dennis

chemsitry
1)100ml sample of solution that is 0.2M in both Naf and Hf has 4.0 ml of 1.0M hcl added to it. calculate the ph change of this soultion .ka =7.2*10^-4 2)40 ml of 0.32M benzoic acid if titrated with 60 ml of 0.2 M naoh. clacilate the ph of the resulting solution at the ...
March 4, 2012 by Anonymous

Chemsitry
At 25 C, only 1.9 g CaSO4 (MM = 136 g/mol) will dissolve in 2.00 L of water. Write the equilibrium expression and calculate the equilibrium constant for the reaction below. CaSO4 (s) ⇋ Ca2+ (aq) + SO42- (aq)
June 13, 2010 by Michelle

Chemsitry II
50.00 mL of 1.0 M HCl and 50.00 mL of 1.0 M NaOH are mixed. The temperature is observed to increase by 10.0 degrees C. How much energy (in J) was absorbed by the calorimeter? Assume a density of the reaction mixture of 1 g/mL. Specific heat of the solution is 5.00 J/g/degree C...
May 31, 2011 by Sarah

chemsitry
Why is the molecule you drew above more hydrophobic than dopamine? Describe the edit(s) that you made and how the change(s) make the new molecule more hydrophobic.
September 17, 2013 by sameua

chemsitry
Why is the molecule you drew above more hydrophobic than dopamine? Describe the edit(s) that you made and how the change(s) make the new molecule more hydrophobic.
September 17, 2013 by sameua

chemsitry
How will the osmotic pressure of an aqueous solution change as evaporation occurs? does it even change? or does it increase? evaporation will increase concentration, correct?
May 1, 2007 by sam

Chemsitry
Consider the equilibrium A(g)=2B(g)+3C(g) at 25 degrees Celsius. When A is loaded into a cylinder at 10 atm and the system is allowed to come to equilibrium, the final pressure is found to be 12.13 atm. What is the standard gibbs free energy of reaction for this reaction.
January 31, 2014 by Anonymous

chemsitry
What ions are very important for the proper fuctioning of biological systems such as nerves and cells? A)alkali earth metals B)hydrogen ions C)oxygen ions D)nitride ions E)alkali metal ions
April 21, 2007 by ninjaturtle

Chemsitry 2
a piece of nickel wire has a diameter of 0.568. if the nickel has a density of 8.90g/cc, how long( in meters) should you cut a piece of wire to obtain 0.0234 moles of nickel?
September 12, 2011 by Smarth

Math
We have an important chemsitry test due and I want to make sure that I do not mess up on my algebra. I am dealing with the integrated rate law, but my question is purely algebraically in nature. I hope, somebody can help me. 1) ln(A) = -kt+ln(B) solve for t solve for k solve ...
May 13, 2013 by Yasemine

chemsitry
calculate the molarity of sodium in 12.4g of sodium acetate diluted in 100mL of ID water, and calculate concentration of both sodium and acetate ion in units of mg/mL,mg/L,and ug/mL?
January 31, 2010 by Samah

chemsitry
how do you find the bond order of OH- and OH+? I know bond order = #bonded e- - #antibonding electron/2 im not sure how to find Oh- and Oh+
May 20, 2008 by Sarah

Chemsitry
If Kc = 6.38 105 for the reaction A(g) ⇀ ↽ 2B(g), what is Kc for the reaction written as 2B(g) ⇀ ↽ A(g)? How would I solve this?
April 26, 2014 by Sara

Chemsitry
During an experiment, a student adds 1.23 g of CaO to 200.0 mL of 0.500 M HCl. The student observes a temperature increase of 5.10 C. Assuming the solution\'s final volume is 200.0 mL, the density if 1.00 g/mL, and the heat capacity is 4.184 J/(gC), calculate the heat of ...
June 26, 2013 by imstupid

Chemsitry
Hi I have done this problem like 15 times when I find the mole I get .8 for HCL and .23 for Naoh and the equilibrium conc i get is negative. then I plug it in and get it wrong. Can someone please help me? Complete the table below: Note: Make simplifying assumptions, do not use...
April 27, 2012 by someone

Chemsitry
I dont understand how to write this equation. Write an equation relating the concentration for a reactant A at t=0 to that at t=t for a first-order reaction. Define all the terms, and give their units. Do the same for a second- order reaction. -Would it be the rate law ...
July 17, 2010 by Jane

chemsitry
What is the formal charge on each of the atoms in the Lewis structure of the PO4 (-3) charge? Draw another possible Lewis structure of the phosphate ion below. Formal charge on P is ? -how do I do this problem.
November 13, 2010 by Sarah

Chemsitry
Stomach acid is essentially 0.10 M HCl. An active ingredient found in a number of popular antacids is CaCO3. Calculate the number of grams of CaCO3 needed to exactly react with 250 mL of stomach acid. CaCO3(s)+ 2HCl(aq)= CO2(g)+ CaCl2(aq)+ H20(l)
November 13, 2012 by Brit

chemsitry
hi I need help with this question please. 1. consider the decomposition of N2O5 in carbon tetrachloride(ccl4) at 45c 2N2O5(soln)-> 4NO2(g)+ O2(g) The reacion is first order in N2O5, with the specific rate constant 6.08*10^-4 per second.calculate the reaction rate under ...
December 8, 2009 by hrithik

Chemsitry
Alpha, beta particles and gamma rays. How does the atomic number and atomic mass number change when a radioisotope decays to produce alpha beta or gamma radiation.
January 16, 2012 by Ryan

Chemsitry
For the following equilibrium process: CO2 + H2 = CO + H2O The equilibrium concentrations of reacting species are: [CO]= .050 M; [H2]= .045 M; [CO2]= .086 M; [H2O]= .040 M. (a) Calculate Kc for the reaction (b) If we add CO2 to increase its concentration to 0.50 mol/L, what ...
August 16, 2008 by Ronnie

Science(Chemsitry)
HNO3 used as a reagent has specific gravity of 1.42g/ml and contains 70% by strength HNO3. Calculate a)Normality Of Acid b)Volume of acid that contains 63g pure acid c)Volume of water required to make 1N solution from 2ml conc.HNO3
June 16, 2011 by Atul

Chemsitry
When 3.75 g of a nonelectrolyte solute is dissolved in 405 mL of water at 25 C, the resulting solution exerts an osmotic pressure of 897 torr. What is molarity? I found molarity to be 0.048. What is the number of moles of solute? to find moles, I multiplied it by .405 and got...
March 1, 2013 by Anonymous

AP Chemsitry
A solution of an unknown monoprotic weak acid was titrated with 0.100 M NaOH. The equivalence point was reached when 37.48 ML of base had been added. From a second buret, exactly 18.74 of 0.100 M HCl were added to the titration solution. The pH was then measured with a pH ...
April 1, 2012 by Keith

Chemsitry - Van Der Waals
The constants "a" and "b" in the van der waals equation are "empirical coefficients". What exactly does that mean? Show that the units for "a" and "b" are appropriate for the the Van der Waals equation?
September 19, 2012 by Indi

Chemsitry
Calculate the molar mass of an unknown molecular compound mixed with solid camphor C10H16O, heated and then cooled giving the following data. show all steps in calculation. mass of unknown: 0.195 g Tf(camphor)= 179.8 degree C Kf(camphor)=-40.0 degree C/m mass of camphor-25.03g...
July 10, 2013 by Kelly

CHEMSITRY
IN THIS EXPERIMENT YOU FILL A PREFROM WITH WATER AND PUT A DRINKING STRAW INTO THE PREFROM AND USE CLAY TO SEAL THE OPENING. It is important to recall that when you first tried it, you were unable to drink, but a small amount of water entered the straw. When the water goes ...
May 20, 2010 by POPCORN

Chemsitry
Nitrogen dioxide, a pollutant in the atmosphere, can combine with water to from nitric acid. One of the possible reactions is shown below. Calculate ∆G0 and Kp for this reaction at 25oC and comment of on the spontaneity of the reaction (MUST plot the data and find ...
April 19, 2013 by Yasemine

Chemsitry
Tris is an abbreviation for tris (hydroxymethyl) aminomethane, which is a weak base. Calculate how many grams of tris (mw=121.14g/mol) are needed to make 25mL of 0.10M tris solution. Calculate how many mL of 0.25M HCl are needed to convert half of the moles of tris present in ...
April 2, 2012 by Cassandra

Chemistry
We're doing gas problems in chemsitry. I have no idea where to even begin on this problem: Air is 20% oxygen and 80% nitrogen. What is the mass of air in an automobile tire of 19.7 L and internal pressure of 46.7 PSI at 24 degrees celsius? (That pressure is the same as the 32 ...
March 29, 2010 by Avalon

chemsitry
c. Use the enthalpy diagram provided above and apply Hesss Law to determine the standard enthalpy of formation for C12O36H20N12 (s) using the results from part (a) and the following values: The standard enthalpy of formation of gaseous carbon dioxide is -393.5 kJ/mol The ...
October 23, 2010 by Nora

Chemsitry
What is the purpose of cell matching? (1 mark) I've been researching for quite a long time now. This question relates to using spectrometry. Can anyone help me? Thanks! I let this question go yesterday because I connected it with cells is biology. On rereading today I see it ...
February 12, 2007 by Eunice

Chemsitry
The Ksp of PbBr2 is 6.60 10^6. What is the molar solubility of PbBr2 in pure water? What is the molar solubility of PbBr2 in 0.500 M KBr solution? What is the molar solubility of PbBr2 in a 0.500 M Pb(NO3)2 solution?
March 17, 2013 by Anon

Organic Chemsitry
By knowing the natural abundance of minor isotopes, it's possible to calculate the relative heights of M+ and M+1 peaks. If natural abundances are 12C - 98.9% and 13C - 1.10%, what are the relative heights, to the nearest 0.1%, of the M+ and M+1 peaks in the mass spectrum of ...
January 27, 2012 by Bobby

chemsitry
Consider the diprotic acid H2A with K1 1*10^-3 and K2= 1*10^-9 . Find pH, [H2A], [HA], and [A2-] for a .2000M solution of H2A b)Find pH, [H2A], [HA], and [A2-] for a .200M solution of HA- c) Find pH, [H2A], [HA], and [A2-] for a .200M solution of A-
April 7, 2013 by Jessica

chemsitry
A sample consisting of 0.025 mol of a solid compound is placed inside a metal cylinder. The cylinder was immersed in a water bath consisting of 10.00 kg of water at an original temperature of 25.00 C. When the compound decomposes, the temperature of the water rises to 29.52 ...
October 23, 2010 by Nora

chemsitry
calculate the molarity of sodium in 12.4g of sodium acetate diluted in 100mL of ID water? and calculate concentration of both sodium and acetate ion in units of mg/mL,mg/L,and ug/mL? and calculate concentration of both sodium and acetate ion in units ppm,ppd?
January 31, 2010 by Samah

Chemsitry
Which of the following is NOT true about the thermodynamic standard state? A. A solid is in its standard state when the atmospheric pressure is 1.00 atm and the temperature is 25C. B. An aqueous solution is in its standard state at a concentration of 1.00 M. C. A gas is in ...
February 25, 2008 by Anonymous

chemsitry
You have been provided 100mL of a 1000ug/ml barium standard what volume of this standard must be diluted into 50mL of ID water to produce a 30 ug/ml standard ? if you given a full 100mL of the same standard provied calculate the amount of standard and final volume required to ...
January 31, 2010 by Samah

Chemsitry II
mole fraction is equal to partial pressure divided by the total pressure Total pressure= sum of partial pressure use PV=nRT where n= number of moles equation become PV/RT=n make sure to convert the temperature to Kelvin and to use 0.0821 for R. V=volume, P=total pressure The ...
May 10, 2007 by Delli

Chemsitry
Which of hte laws of thermodynamics provides a criterion for spontaneity? the zeroth law, the first law, the second law, and the third law? This site will give you zeroth, first, second, and third laws. You may need to scroll down a little but it on the right of center of the ...
April 27, 2007 by Cindy

chemsitry
b. The decomposition reaction may be written in this form: C12O36H20N12 (s) → 12CO2 (g) + O2 (g) + 6N2 (g) + 10H2O (l) In the enthalpy diagram below, the arrows represent standard enthalpy reactions. (3) denotes the standard enthalpy of decomposition of C12O36H20N12 (s...
October 23, 2010 by Nora

Chemsitry (Check)
Fill In The Blanks I have Sharing for the first blank and Single for the second. A _______ pair of valence electrons consitutes a _______ covalent bond. Shared/Double. See http://www.chemguide.co.uk/atoms/bonding/doublebonds.html I would have gone with shared and single, also...
December 16, 2006 by Bryan

Chemsitry II
The partial pressure of CH4(g) is 0.185 atm and that of O2(g) is 0.300 atm in a mixture of the two gases. a) What is the mole fraction of each gas in the mixture? b) If the mixture occupies a volume of 11.5 L at 65 degress C, calculate the total number of moles of gas in the ...
May 10, 2007 by Jayd

Chemsitry
Hello. I'm not n=sure about these answers so i was wondering if someone could check them out? 27, A: Which is a stronger acid - sulfuric or carbonic acid? (Answer: Sulfuric acid.) 27, B: Imagine you have two glasses. One contains a solution of carbonic acid. The other contains...
May 11, 2009 by CRCAWF

Physics - Ionic bonding
Hello My exams are coming I'm a straight A student .. the problem however is : My textbooks , teacher and every piece of work that he gives us is complicated can someone explain me how Ionic Bonding works and when we're taking about this table here can someone explain it to me...
June 7, 2007 by Sasha

Chemsitry
How do yuo find the amount in moles of excess reactant that reamins Please retype that, minding your spelling. =) Can you please show me how to determine the amount in moles of excess reactant that remains Sorry about the mistakes =) This is part of an excess reagent problem. ...
February 24, 2007 by Beautiful

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