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October 23, 2014

Search: CHM

Number of results: 117

advanced biology
chemical properties describe how a _____ changes into a new substance. This site will give you a definition and examples. http://www.elmhurst.edu/~chm/vchembook/105Achemprop.html
August 19, 2007 by emily

CHM 152
At 20oC, a 2.32 M aqueous solution of Ammonium Chloride has a density of 1.0344g/ml. WHat is the molality of Ammonium Chloride in the solution? The formula weight of NH4Cl is 53.50 g/mol?? I am not sure how to incorporate the density into the problem to come up with how to ...
June 10, 2010 by Car

science
what is carbon cycling http://www.elmhurst.edu/~chm/vchembook/306carbon.html A thing made out of carbon. It is in a shape like a circle
June 14, 2005 by Josh

chemistry
hi, I am wondering if benzyl acetate is polar or nonpolar? because it has a non polar benzene ring but also it has the ester bit attached so i am confused. Also i cant seem to understand the vander waal forces that are in it. if anybody could help that would be super A little ...
December 18, 2006 by steff

CHM 300
if the pKa of HCN is 9.21,what it its Ka?
October 1, 2014 by Nurcan

CHM
Why it is OK to prepare the titrant solution so inaccurately?
September 19, 2014 by Jamika

CHM
what is meant by the term "free calcium"?
September 29, 2014 by Hanu

CHM 157
calculate the lattice energy of CaO
April 8, 2008 by Anonymous

chm
determing concentration by spectroscopy lab discussion?
April 4, 2011 by iqra

CHM
How to balance the following equation: Na(s) + H2O(l) yields?
November 27, 2012 by Adam

chm
how does CO2 affect the titer of a solution of NaOH ?
September 13, 2014 by josh

chm
I need to find the mass of 0.0225 mole of NH3?
September 29, 2010 by cindy

Analytical CHM Lab
why is NaOH a poor primary standard ?
September 13, 2014 by Noor

chm
The molar solubility of PbBr2 at 250C is 1.0x10^-2. Calculate the Ksp.
June 27, 2010 by ami

CHM
Calculate the solubility of Cu(oh)2 in grams per liters of solution if Ksp for Cu(OH)2 IS 4.8X 10^-20
June 27, 2010 by ami

org chm
how many grams of KOH are needed to make 590 ml of a solution with a pH of 11.35?
November 17, 2010 by carol

chm
How many valence shell electrons would you expect for an S2- ion? 8 Am I correct.
February 18, 2013 by luck

ChM
Calculate the pressure exerted by 1.2 mol of gas in a volume of 28.2 L and at a temperature of 61 C.
July 6, 2013 by Anonymous

CHM 300
Explain why I2 is not a good primary standard? why is this an iodometric procedure?
September 26, 2014 by Janu

chm
What is the theoretical yield of iron if we begin the reaction with 10.5g of AL (assume an excess of Fe2)3)
October 21, 2011 by karol

Organic CHM II
Define the following sets of term: α- and β- notation
May 6, 2014 by rtyeu

Analytical CHM 300
which rating system gives the analyst the most information?
September 3, 2014 by Numan

ANALYTICAL CHM
Describe the correct technique for reading the meniscus of a solution in the buret.
September 6, 2014 by Josh

CHM
How might chromophores, auxochromes, and solubilizing groups be responsible for the position of dyes on a chromatogram?
November 13, 2012 by Jerett

CHM
In the chemical formula of ammonium sulfate, (NH4)2SO4, how many hydrogen atoms are present? 4
January 27, 2013 by jakey

Organic CHM II
What are the most important monosaccarides in biological systems? glucose and fructose?? is that correct?
May 5, 2014 by rtyeu

chm
Calculate the theoretical amounts of 0.1000 M NaOH titrant used to titrate 0.8 and 0.9 g KHP
September 14, 2014 by guru

CHM
Calculate the theoretical amounts of 0.1000 M NaOH titrant used to titrate 0.8 and 0.9 g KHP
September 14, 2014 by Helin

CHM
what other compounds may be present at the trace level that would interfere with this titration? (EDTA)
September 29, 2014 by Janu

CHM 152
How many gram of Fe+3 are required to make 1.0 L of an aqueous solution of 10 ppm Fe+3? Assume density of water is 1.00 g/mL.
June 8, 2010 by Car

chm
If 0.0490g of AgIO3 DISOLVES per liter of solution, calculate the solubility product constant.
June 27, 2010 by ami

CHM
Calculate the percent ionization of hydrazoic acid (HN3) in solutions of each of the following concentrations A) 0.377 M B) 0.107 M C) 4.16*10^-2 M Ka= 1.9*10^-5
October 8, 2012 by Jordan

CHM
suggest an alternative indicator for the standardization reaction. Explain the rationale behind your choice. Used 10 g of KHP
September 14, 2014 by Jessica

CHM
we will do a project on this topic ;HPLC with fluorescence detection to quantify the amounts of various preservatives in several kinds of soda. so what can be analyzed ?
September 28, 2014 by Cani

CHM
Which of the following is not an example of a physical change? is this the right Answer accidentally leaving a piece of toast in the toaster until it is completely black
January 27, 2013 by Jakey

chm
If a neutral element has 8 neutrons and 7 electrons, which expression correctly identifies the element?
February 27, 2013 by jj

CHM
How many liters in volume are occupied by 250 liters of bromine at STP?
March 17, 2013 by Anonymous

chm
What is the pH of the solution obtained by mixing 30.00mL OF 0.250M HCL AND 30.00mL OF 0.125M NaOH?
March 31, 2010 by ami

ANALYTICAL CHM
What are the possible sources of error in using a graduated pipet? in using a buret?
September 6, 2014 by jessy

analytical chm
Analytical Balance which weighing method does one use when drying constant weight? Why?
September 7, 2014 by harune

Chm 203
On a size exclusion separation column (e.g. Sephadex) would you expect the longer or shorter chain length compound to be eluted first? Why? Explain? Thanx!
September 24, 2014 by Anonymous

CHM 152
For the system 2A (g) + B( g) = 2C (g), if the initial concentration of pure C is 1.00 M, the equilibrium concentration is 0.40 M. What is the value of Kc? Choose one answer. a. 5.0 b. 0.45 c. 0.67 d. 2.2 e. 1.5
March 26, 2010 by AMI

Chm
What is the molarity of a saturated solution of potassium sulfate if the solubility is 13 g per 100 g H2O at 25C? The density of the solution is 1.1 g/mL
January 17, 2013 by Chris

CHM LAB
we are doing complexometric titration for the data sheet it askes to find mass of CaCO3 in sample how do I find it ?
September 29, 2014 by Hurine

chm
Which of the following is a covalent compound composed of nonpolar covalent bonds? Answer >>H2 H2O CF4 CH4 NaF
February 26, 2013 by jj

CHM
Calculate the molecular weight of a small protein if a 0.32 g sample dissolved in 161 mL of H2O has an osmotic pressure of 9.0 mmHg at 25 degree celcius. (R=0.0821 L X atm/K X mol)
January 13, 2013 by Robby

CHM 152
A 0.750 L bottle of a French Merlot is said to contain 12.5% alcohol by volume. How much of the liquid, in mL, in the bottle is water?
June 8, 2010 by Car

CHM formula needed, pls?
How many milliliters of a 0.25 M sucrose solution contain 2.0 grams? The molar mass of sucrose (C12H22O11 ) is 342.3 g/mol.
November 19, 2012 by Vc

Analytical CHM
Chemical Reagent: Iodine (resublimed crystals Lot# 127287) What is the numerical health hazard for this reagent? Explain what this means
September 5, 2014 by Nural

Analytical CHM Lab
Chemical reagent: Iodine (resublimed crystals lot# 127287) What is the numerical fire hazard for this reagent?Explain what this means
September 5, 2014 by Nural

CHM
Predict whether the following bonds are ionic, covalent, or polar covalent based on the bonding atoms electronegativities: N2 The Al-O bond in Al2O3 MgO CuS
December 3, 2012 by Lisa

CHM
Consider the following reaction: HCN <--> H+ + CN- delta H = 315kJ If 1.00 mole of CN- in the form of NaCN was added to equilibrium mixture, describe the effect on [H+], [HCN], [CN-], pH, and heat.
April 16, 2013 by Valerie

CHM
How many milliliters of a 0.25 M sucrose solution contain 2.0 grams? The molar mass of sucrose (C12H22O11 ) is 342.3 g/mol. Need the formula to understand how to continue with more problems.
November 19, 2012 by V

Chm
8.08g of KNO3 were required to saturate 25g of distilled water at 20oC. Calculate the solubility of the solute in a) g/dm^3 of water b) mol/dm^3 of water
June 10, 2011 by Ife

Organic CHM II
With what starting material are all lipids are built? Describe the process that a long carbon chain is rearranged into a multi-cyclic molecule that is basis for steroids? Please explain in detail
May 5, 2014 by Slinahu

chm
An unknown radioactive substance has a half-life of 3.20 . If 34.8 of the substance is currently present, what mass was present 8.00 hours ago?
February 10, 2012 by cp

CHM Lab
How much titrant will be required if your EDTA titrant is exactly 0.01 M and you weighed out exactly 0.4 g calcium carbonate?
September 21, 2014 by Haju

chm
At a certain temperature the concentration of was 0.400 and that of was 0.235 . At equilibrium the concentration of was found to be 0.250 . What is the value of at this temperature?
February 9, 2012 by aa

CHM
How much titrant will be required if your EDTA titrant is exactly 0.01 M and you weighed out exactly 0.4 g calcium carbonate?
September 21, 2014 by Jesica

chm
Calculate the PH OF A SOLUTION prepared by mixing 15.0mL OF 0.50 M OF NaOH AND 30.0mL OF 0.50 M BENZOIC ACID SOLUTION?( Benzoicacid is monoprotic and its dissociation constant is 6.5*10^-5)
March 31, 2010 by ami

Analytical CHM
Rank the following items in order of accuracy: volumetric pipet, beaker,buret,erlenmeyer flask,volumetric flask
September 3, 2014 by Neda

Organic CHM Lab
a) what is meant by the term flooding of the fractionating column and what causes it? b) Assume that no azeotropes are formed, would it be easier to separate n-hexane and benzene or n-hexane and toluene by distillation? expalin? Thank you!
September 9, 2014 by Kim

Chm Help Please!!!
What is the boiling point of a solution of benzene contain 0.2 moles of a non volatile solute in 125 grams of benzene given that pure benzene has a b.p. of 80.1 Celcius and a Kbp of +2.53 C/m. Thanks!
September 9, 2014 by Layla

CHM 300
We did experiment: Spectrophotometry(Determination of iron with 1,10-Phenanthroline) It asks me to find the molar absorptivity of the Fe-phenanthroline complex? How do i find it ? please eplain.
October 20, 2014 by Malik

ionic compounds!
why are ionic compounds abundant in nature? Betty, I don't know how to answer your question. Abundant compared to what? How is abundant defined? I would think there are more covalent compounds in nature than ionic compounds but I may be wrong. Can you clarify the question a ...
June 17, 2006 by betty

chm
gunpowder is a mixture of potassium nitrate , sulfur and carbon in th proportion (by mass) of 6:1:1 (KNO3;S:C). A typical riflr shell contains 3.2 gunpowder. How many moles of each compnent are there in our sample gunpowder?
October 27, 2009 by Brittany

Chm Help Please!!!
you wish to purify by distillation a material that has a boiling point of 205 C and reacts with air but this material will decompose if heated above 150 C. How would you set up the system to distill this material? Thanks!
September 9, 2014 by Kayla

CHM
From the following: 1) pure water 2) 0.01 m solution of table sugar (C12H22O11) 3) 0.01 m solution of NaCl 4) 0.01 m solution of CaCl2 Choose the one with the largest van't Hoff factor and hence the lowest freezing point.
February 9, 2010 by CC

Chm General 2
if a student doing an experiment failed to dry the KHP before using it to standarize the NaOH solution. A) Would her calculated molarity of the NaOH solution probably be too hight or too Low?
March 23, 2011 by Karla

Chm 2046
The normal boiling point of liquid ethanol is 351 K. Assuming that its molar heat of vaporization is constant at 37.5 kJ/mol, the boiling point of C2H5OH when the external pressure is 1.35 atm is K.
February 1, 2013 by Camaro Lover

chm
How would you classify the following material?swimming pool water homogeneous mixture<<< heterogeneous mixture a pure element a pure compound depends on how many children have been in it
February 23, 2013 by JJ

CHM 152
The freezing point of an aqueous solution of glucose was measured to be -1.52 oC. What is the osmotic pressure, in atm, of 100 mL of this solution at 25.0 oC? (Kf = 1.86 oC/m) When I calculated it out I got 16.79 atm but the answer was wrong dont know what I messed up on.
June 10, 2010 by Car

CHM 1010
Under pressure of 862kPa, a gas has a volume of 752ml. The pressure is increased, without changing the temperature, until the volume is 624ml. What is the new pressure
April 1, 2013 by Jocelyn

chm
The Lewis dot structure of ammonia, NH3, reveals that it has one lone pair of electrons and three bonds (each to a hydrogen) around the central nitrogen atom. According to VSEPR theory, what molecular shape will it have? i thought it was tetrahedral but its wrong. what and why...
February 18, 2013 by luck

chm
Silver chloride, often used in silver plating, contains 75.27% .Calculate the mass of silver chloride required to plate 195 of pure silver.
February 10, 2011 by ahmad

CHM 152
An automobile antifreeze contains equal volumes of ethylene glycol (d=1.114 g/mL and FW = 62.07) and water (d=1.00 g/mL) at 25oC. The solution has a density of 1.06 g/mL. What is the molarity of ethylene glycol in the solution?
June 8, 2010 by Car

CHM
Assuming the density of acetic acid solution is 1.0 g/mL, determine the volume of the acetic acid solution necessary to neutralize 25.0 mL of 0.10 M NaOH. Record this calculation on your report sheet
January 25, 2011 by JACK

chm
what is ph of a solution made by mixing 55ml of 0.12M in Formaic acid and 65ml of 0.12M of Sodium Foramte? For Ka of Formaic acid is 1.4x10^-4
June 27, 2010 by ami

CHM
Some of the cyclohexane solvent vaporized during the temperature versus time measurement. Will this loss of cyclohexane result in its freezing point being recorded as too high, too low or unaffected? Explain. Please someone explain this to me I don't understand it...Thank you
October 10, 2012 by Adam

Gen Chm 2
What determines the greatest buffer capacity when looking at solutions? The professor said he would have a list of solutions on the test and we choose the one with the best buffer capacity.
October 17, 2013 by Kyle

CHM 152
The activation energy for a reaction is 37.6 kJ/mole. The rate constant for the reaction is 5.4 x 10-3 s-1 at 45 oC, Calculate the rate constant at 145 oC.
June 10, 2010 by Car

chm 2
On the same type of problem as the previous one, it is now asking the pH of 1ml of NaOH plus 50ml water. If i solve for pOH taking .001ml / .051, i get the same number as before, can i just subtract the number from 14 to get pH of the basic solution? 12.29 was what i came up ...
October 14, 2013 by Kyle

CHM 300
Experiment: Redox titration;determination of ascorbic acid by an iodometric back-titration Why is sodium carbonate added to the thiosulfate solution ? why is the water used for preparing the thiosulfate solution boiled ?
September 26, 2014 by Jennifer

biology
What forms of energy are involved in metabolism? Since this is not my area of expertise, I searched Google under the key words "metabolism energy" to get these possible sources: http://www.elmhurst.edu/~chm/vchembook/5900verviewmet.html http://ds9a.nl/metabolism/ http://staff....
April 10, 2007 by laura

chm
The specific heat of fat is 0.45 cal/(g) , and the density of fat is 0.94 g/cm^3 . How much energy (in calories) is needed to heat 22 cm^3 of fat from room temperature (25 ^\circ {\rm C}) to its melting point (35 ^\circ {\rm C})?
September 12, 2013 by Anonymous

chm
The mass of Oceanis 1.8*10 to 21 kg.The ocean contains 1.076%sodium ion,Na+what is mass of sodium in ocean
August 31, 2010 by mark

CHM
A sample of gas has an initial volume of 2.4 L at a pressure of 855 mm Hg and a temperature of 298K. If the gas is heated to a temperature of 387 K and expanded to a volume of 4.1 L, what is its final pressure in mm of mercury?
July 6, 2013 by A

CHM 101
The food dyes contain propylene glycol in addition to the dyes and water. The candy shells contain sucrose, corn syrup, corn starch and gum acacia. Do you think this affects the movement of the dyes on the chromatography paper?
March 12, 2011 by Lisa

chm
Liquid nitrogen is obtained by condensing gaseous nitrogen found in air and boils at 77.36 K. At the boiling point, the density of the liquid is 809 g/L and that of the gas 4.566 g/L. How many liters of liquid nitrogen are produced when 500.0 L of nitrogen gas are liquefied ...
February 2, 2011 by ami

CHM
Given the initial concentrations of 0.10 atm NO2 and 0.10 atm N2O4 in a 1.0 L flask, what will be the equilibrium partial pressure of NO2? N2O4(g)=2NO2 Kp=0.660at319K Choose one answer. a. 0.10 atm b. 0.31 atm c. 0.045 atm d. 0.72 atm e. 0.19 atm
March 28, 2010 by AMI

chm
Why are the atomic masses listed in the periodic table not whole numbers? Answer Scientists have yet to make the precise measurements. That would be too much of a coincidence. ??>>The atomic masses are average atomic masses. or >>Today's instruments are able to ...
February 23, 2013 by jj

Analytical CHM
Rank the following items in order of accuracy when they are used for their intended purpose: Volumetric pipet, beaker, Erlenmeyer flask, MOHR pipet, graduated cylinder, volumetric flask, buret. Explain your asnwer below Most accurate 1. 2. 3. 4. 5. 6. Least accurate 7. ...
September 5, 2014 by Joshua

Analytical CHM
For both the 2-(acetyloxy) benzoic acid and the acetic acid, which endpoint determination method will give the most reliable endpoint? and Why is this method most reliable ? Please explain in detail
October 15, 2014 by Malik

chm
A cylinder with a movable piston contains 2.00 of helium,He, at room temperature. More helium was added to the cylinder and the volume was adjusted so that the gas pressure remained the same. How many grams of helium were added to the cylinder if the volume was changed from 2....
October 10, 2008 by sarah

Chm
Air is about 78.0% nitrogen molecules and 21.0% oxygen molecules. Several other gases make up the remaining 1% of air molecules.What is the partial pressure of nitrogen in air at atmospheric pressure (1 atm)? Assume ideal behavior.
October 10, 2008 by Karina

CHM 152
Consider the following equilibrium: PCl5 = PCl3+ Cl2 5.0 moles of are placed in a 10.0 L flask at 200 C and allowed to come to equilibrium. Analysis shows that 1.0 mole of is present in the equilibrium mixture. How many moles of are present at equilibrium. Choose one answer. ...
March 26, 2010 by AMI

CHM general 2
Indicated whether the calculated molarity of NaOH would be lower or higher Than the real value; or unaffected? a) the water of the NaOH solution is not boiled and cooler before the solution is prepared b) The buret, wet with water, is not rinsed with NaOH solution before filling
February 23, 2011 by Grettel

CHM
A mixture of three gases exert a total pressure of 753 mm Hg.If Gas #1 has a partial pressure of 289 mm Hg and Gas #2 has a partial pressure of 122 mm Hg, what must the partial pressure be of gas #3?
July 6, 2013 by Anonymous

Analytical CHM
Calculate the theoretical amounts of 0.1000 M NaOH titrant used to titrate 0.8 and 0.9 g KHP Please show step by step solution , i need the correct significant figures and units to finish up the rest of the lab correctly i found the answer but for some reason ,using my answers...
September 15, 2014 by Jessy

CHM
Need help please Which of the following equations has the coefficients 2,1,1,2 when it is balanced? Fe2O3 + HClO4 → Fe(ClO4)3 + H2O Ca(OH)2 + H3PO4 → Ca3(PO4)2 + H2O KOH + H2SO4 → K2SO4 + H2O Ba(OH)2 + P4O10 → Ba3(PO4)2 + H2O Al2O3 + H2SeO4 → Al2(...
October 10, 2012 by Aliyah

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