Wednesday

January 18, 2017
Number of results: 62,757

**Chemistry ASAP**

Using a table of standard electrode potentials (such as the one in your textbook), calculate the standard cell potential for a cell made by placing a zinc electrode in a Zn2+(aq) solution which is connected by an electrolyte to a Ag+ (aq) solution containing a silver electrode...

*May 13, 2014 by Tyler*

**chemistry**

Glycerin (C3H8O3) is a nonvolatile liquid. What is the vapor pressure of a solution made by adding 180. g of glycerin to 321 mL of H2O at 39.8°C? The vapor pressure of pure water at 39.8°C is 54.74 torr and its density is 0.992 g/cm3.

*May 4, 2010 by bob*

**chemistry**

Glycerin, C3H8O3, is a nonvolatile liquid. What is the vapor pressure of a solution made by adding 164 g of glycerin to 325 mL of H2O at 39.8°C? The vapor pressure of pure water at 39.8°C is 54.74 torr and its density is 0.992 g/cm3.

*February 12, 2011 by tay*

**chem**

Determine the volume of 0.240 M KOH solution required to neutralize each of the following samples of sulfuric acid. The neutralization reaction is shown below. H2SO4(aq) + 2 KOH(aq)--> K2SO4(aq) + 2 H2O(l) (a) 26 mL of 0.240 M H2SO4 thanks

*March 11, 2011 by Abby*

**Science**

Stacy has .55kg water sample at 1 atm pressure and 40 degrees celsius. She heats it to 90 degrees Celsius, maintaining constant pressure. How much heat was absorbed by the solution during the course of this operation? (CP of H2O (l) = 4.18 J/g )

*December 5, 2012 by Marketa*

**ap chem**

Bismuth can be electrolytically reduced according to the following reaction: BiO(+)+ 2H(+)+ 3e¯ >>> Bi + H2O How many grams of bismuth can be reduced by applying a 5.60 A current for 23.8 min. to a solution containing BiO+ ions (assuming 100% efficiency)?

*May 22, 2015 by Anonymous*

**Chemistry**

A laboratory technician is required to prepare a quarter normal saline solution (0.22% w/v) from the stock normal saline solution. 1. What is the dilution factor required? I have 4-fold dilution - is that correct? 2. Ise this dilution factor to calculate the volume of stock ...

*December 14, 2010 by Korina*

**Chemistry**

A solution is prepared by mixing 0.12 L of 0.12 M sodium chloride with 0.22L of a 0.19M MgCl2 solution.What volume of a 0.22 M silver nitrate solution is required to precipitate all the Cl- ion in the solution as AgCl ?

*March 13, 2010 by Abril*

**college algebra (maths 112)**

To conduct a new experiment, a scientist needs a 23% salt water solution. How much of a 13% solution must be mixed with 45 quarts of a 32% solution to get the proper solution?

*February 24, 2011 by Anonymous*

**science**

solution A was prepared by dissolving 0.63g of HNO3 in 100cm3 solution. Solution B is a sodium calcium hydroxide solution of unknown concentration. state a balanced chemical equation for the reaction

*August 25, 2015 by Zoe*

**Chemistry**

The specific heat of a solution is X J/g*degreesC and its density is Y g/mL. The solution was formed by combining Z mL of solution A with Z mL of solution B, with each solution initially at J degreesC. The final temperature of the combined solutions is D. The heat capacity of ...

*April 2, 2010 by Fred*

**math**

A pharmacist wishes to mix a solution that is 6% Minocidil. She has on hand 60 ml of a 3% solution and wishes to add some 8% solution to obtain the desired 6% solution. How much 8% solution should she add?

*January 17, 2012 by Hali*

**chemistry**

A solution contains 4.44% by mass of NaI in water. Calculate the molarity of the NaI, if the density of the solution is 1.2711 g mL-1. i got the answer to be 8.48 M... the percent mass is irrelevant information, right? i figured out the answer just by the given density alone.

*November 11, 2007 by keely*

**Chem**

1) A saturated solution of the slightly soluble salt MA3 is 1.4 ×10^–3 M in MA3. What is its Ksp value? 2) A 20.0 mL sample of NaIO3 was treated with an excess of KI and HCl and the iodine produced titrated with 0.05125 M Na2S2O3. 19.35 mL of Na2S2O3 solution were required ...

*November 8, 2015 by Brad*

**Chemistry**

1) A saturated solution of the slightly soluble salt MA3 is 1.4 ×10^–3 M in MA3. What is its Ksp value? 2) A 20.0 mL sample of NaIO3 was treated with an excess of KI and HCl and the iodine produced titrated with 0.05125 M Na2S2O3. 19.35 mL of Na2S2O3 solution were required ...

*November 9, 2015 by Brad*

**chemistry please help!!**

For the reation: C3H8+5 02 =3 CO2+4 H2O How many moles of C3H8 are needed to make 3.60 grams of H2O? I think the ans is 0.05 moles c3h8

*October 25, 2010 by Lillian*

**Algebra**

For the following equation, state the value of the discriminant and then describe the nature of the solutions. -7x^2+3x-4=0 What is the value of the disriminant? Does the equation have two imaginary solutions, two real solutions, or one real solution?

*March 2, 2009 by Sam*

**Inorganic chemistry**

Calculate E naught cell for the reaction b 5Cd(s) + 2MnO4-(aq) + 16H+(aq) ==> 5Cd^2+(aq) = 2Mn^2+(aq) + 8H2O(l) given the following standard reduction potentials MnO4^-(aq) + 8H^+(aq) = 5e^- ==> Mn^2+(aq) + 4 H2O(l) E naught = +1.52V Cd^2+(aq) + 2e^- ==> Cd(s) E ...

*April 11, 2009 by Steve*

**Chemistry**

a domestic cleaner contains concentrated hydrochloric acid as the active ingredient. a titration experiment was carried out to determine the concentration of hydrochloric acid in the domestic cleanser. 20.0mL of the cleanser were diluted to 250.0mL with distilled water. 25.0mL...

*December 26, 2016 by Darth Chan*

**science**

Concentrated sulfuric acid (18.4 molar H2SO4) has a density of 1.84 grams per milliliter. After dilution with water to 5.20 molar, the solution has a density of 1.38 grams per milliliter and can be used as an electrolyte in lead storage batteries for automobiles. 1. Calculate ...

*October 24, 2007 by raksha*

**chemistry**

Ammonium carbonate decomposes upon heating according to the following balanced equation: (NH4)2CO3(s)-->2 NH3(g)+CO2(g)+H2O(g) Calculate the total volume of gas produced at 25 C and 1.07atm by the complete decomposition of 11.86 g of ammonium carbonate.

*April 16, 2010 by jason*

**Chemistry**

Ammonium carbonate decomposes upon heating according to the following balanced equation: (NH4)2CO3(s)-->2 NH3(g)+CO2(g)+H2O(g) Calculate the total volume of gas produced at 25 C and 1.07atm by the complete decomposition of 11.86 g of ammonium carbonate.

*April 16, 2010 by Zoe*

**Chemistry**

Ammonium carbonate decomposes upon heating according to the following balanced equation: (NH4)2CO3(s)-->2 NH3(g)+CO2(g)+H2O(g) Calculate the total volume of gas produced at 25 C and 1.07atm by the complete decomposition of 11.86 g of ammonium carbonate.

*April 16, 2010 by Zoe*

**Chemistry**

Using standard enthalpies information, calculate the standard enthalpy change for this reaction: a) (thermite reaction) 2Al(s) + Fe2O3(s) = Al2O3(s) + 2Fe(s) b) Mg(OH)2(s) = MgO(s) + H2O(I) c) N2O4(g) + 4H2(g) = N2(g) + 4H2O(g) d) SiCl4(I) + 2H2O(I) = SiO2(s) + 4HCI(g)

*July 3, 2014 by Brett*

**Chemistry**

Using standard enthalpies information, calculate the standard enthalpy change for this reaction. a)(thermite reaction) 2Al(s) + Fe2O3(s) = Al2O3(s) + 2Fe(s) b)Mg(OH)2(s) = MgO(s) + H2O(I) c)N2O4(g) + 4H2(g) = N2(g) + 4H2O(g) d)SiCl4(I) + 2H2O(I) = SiO2(s) + 4HCI(g)

*July 3, 2014 by Dan*

**college chem**

Calculate the molar enthalpy of reaction standard enthalpy of formation below. H20 = -285.8 kj/mole H+ = 0.0 kj/mole OH- = -229.9 kj/mol H+(aq) + OH-(aq)→H2O(l) For this, don't you do the summation of products x stoichemtry + the sum of reactants x stoich. from there I'm...

*November 20, 2014 by sam*

**Calculus!!**

Consider the differential equation given by dy/dx = xy/2. A. Let y=f(x) be the particular solution to the given differential equation with the initial condition. Based on the slope field, how does the value of f(0.2) compare to f(0)? Justify your answer. B. Find the particular...

*April 23, 2016 by Anonymous*

**Chemistry**

2 H2S (g) + SO2 (g) <===> ƒnƒn3 S (s) + 2 H2O (g) 1) At 298 K, the standard enthalpy change, H¢X, for the reaction represented below is -145 kilojoules. (a) Predict the sign of the standard entropy change, S¢X, for the reaction. Explain the basis foryour prediction...

*April 29, 2008 by JJ*

**chemistry**

An ideal solution contains 40 mole % of A and 60 mole % of B at 80 degrees C. The vapor pressure of pure A and B at this temp are 480 torr and 890 torr. Calculate the vapor pressure of the solution.

*October 7, 2010 by Anonymous*

**chemistry**

An ethylene glycol solution contains 18.2g of ethylene glycol (C2H6O2) in 85.4mL of water. Calculate the freezing point and boiling point of the solution. (Assume a density of 1.00 g/mL for water.)

*November 19, 2014 by Anon*

**Chemistry**

Calculate the concentration of chloride ions in the following solution. 73.28g of sodium chloride in 862. mL of solution. would it be 73.28g x 2 / 58.44g NaCl = 2.50 mol of Cl 2.50 mol Cl / .862 L = 2.91 M Cl

*September 18, 2016 by Anonymous*

**Chemistry**

Calculate DeltaHrxn for the following reaction: C + H2O --> CO + H2 Use the following: C + O2 --> CO2 DeltaH = -393.5 kJ 2CO + O2 --> 2CO2 DeltaH = -566.0 kJ 2H2 + O2 --> 2H2O Delta H = -483.6 kJ DeltaHrxn = ?

*March 20, 2012 by Chemistry*

**Chemistry**

The balanced equation for the decomposition of sodium bicarbonate is 2 NaHCO3 (s) --> Na2CO3 (s) + H2O (g) + CO2 (g)delta H 129.2. Using the enthalpies of formation, calculate the enthalpy of formation of sodium bicarbonate.

*April 30, 2013 by Laura*

**Chemistry**

10.5g of zinc was heated to a constant mass and the residue treated with excess Hcl: ZnCo3+Hcl-----ZnCl2+Co2+H2O. Calculate the mass of zinc chloride that would be obtained

*April 1, 2016 by Peace*

**Math**

1. Is the equation true, false, or open? 4y 8 = 6y + 3 2. Which value is a solution of the equation 2 - 8x = -6? 3. Which ordered pair is a solution of the equation y - x - 4? 4. Which ordered pair is a solution of the equation y = 4x? 5. Which ordered pair is the solution of ...

*November 29, 2016 by Robin Kwan*

**Math**

Determine the solution to the initial value differential equation: y′+2*y^2*e^(5*x)= 0 y(0)=2

*October 21, 2009 by AK*

**algebra**

I want to make sure that I understand how to do this problem. What is the value of x if 3/2x-2=15 + x? Would the solution be 2/9?

*May 27, 2010 by anonymous*

**math**

state the value of the discriminant and the discribe the nature of the solution 20x^2-8x-17=0

*August 29, 2010 by marie*

**math**

Use the intermediate value theorem to verity that x^4+X-3=0 has a solution in the interval(1,2)

*October 10, 2010 by Anonymous*

**math **

for each inequality tell whether the given value is a solution. a.x+8 > 15 x=4 b. 6x __<_ 30 x= -8 c. 4y-7<12 y=-1 d. z+2 _>__4+3z z=2

*January 4, 2011 by kattie*

**algebra2**

What is the value of x in the solution to the system y = 4x + 3 and 3x + 2y = -16? (Round to the nearest integer if necessary.)

*February 1, 2011 by meghan*

**MATH**

Find the solution of the given initial value problem. ty'+(t+1)y=t y(ln2)=0 t < 0

*February 22, 2011 by ALEX *

**calculus**

Please help find the solution to the initial value problem dy/dx=(1+2cos^2 x)/y with(y>0), and y=1 when x=0. Thanks.

*April 29, 2011 by John*

**chemistry**

What will be value of molarity and strength %w/v respectively 30V H2O2 solution

*August 23, 2011 by Aayush*

**mathematics please help!**

For what value of k does the system below not have a unique solution? -1x + 7y + 2z = 6 2x + 1y + kz = -11 3x - 6y - 2z = -25 A.5 B.0 C.-2 D.-8

*July 22, 2012 by True*

**math help please**

For the following system of equations, what is the x-value of the solution? –x + 2y = 6 6y = x + 18 A.-18 B.0 C.-6 D.3 I think its B??

*November 24, 2012 by Deborah*

**Science**

A solution has been prepared by dissolving 0.63 g of HNO3 in 100 ml.What is its pH value ?

*December 8, 2016 by Anindita*

**Chemistry**

K2O + H2O ==> ? KOH?? But it cannot be balanced. So would the product be KOH when K2O is dissolved in H2O? Thanks you!

*May 31, 2009 by Anonymous*

**chemistry**

what are the acids, bases, conjugated nacids and conjugated bases of the equation H2O+H2O->OH-+H3O?

*May 5, 2011 by jacob*

**Chem**

@20 degree solubility-22g Cu SO4/100g H2O @ 20 degree C is 6g Cu SO4/25 g H2O saturated?

*December 2, 2011 by Tammy*

**chemistry**

A sample of water is known to contain 1.51 × 10^24 H2O molecules. How many moles of H2O molecules are present in the sample?

*March 22, 2016 by Dave*

**Chemistry (Check)**

Completion. struggling with this....I got 1) 2)Precision 3)experimental value 4) 5) The ___1___ of a measurement describes how close the measurement comes to the true value. The ____2___ of a measurement depends on its reproducibilty. An ___3___ is a value measured in the lab...

*January 14, 2007 by Bryan*

**Organic Chemistry - Extraction**

You have 100 mL of a solution of benzoic acid in water; the amount of benzoic acid in the solution is estimated to be about 0.30 g. The distribution coefficient of benzoic acid in diethyl ether and water is approximately 10. Calculate the amount of acid that would be left in ...

*October 3, 2010 by Camille*

**Chemistry**

CaCl2(s) Ca2+(aq) + 2 Cl-(aq) H = -81.5 kJ A 14.0 g sample of CaCl2 is dissolved in 130. g of water, with both substances at 25.0°C. Calculate the final temperature of the solution assuming no heat lost to the surroundings and assuming the solution has a specific heat ...

*November 10, 2007 by Joe*

**chemistry**

A solution is prepared by mixing 0.0400 mol CH2Cl2 and 0.0800 mol CH2Br2 at 25 degrees C. Assume solution is ideal, calculate the composition of the vapor (in terms of mole fractions) at 25 C. At 25 C, vaporpressure of pure CH2Cl2 and pure CH2Br2 are 133 and 11.4 torr.

*March 7, 2010 by Sara*

**Chemistry**

A student mixes 100.0 mL of 0.300 mol/L silver nitrate solution with 100.0 mL of 0.300 mol/L calcium chloride solution. a) Determine the theoretical yield of the precipitate. b) If the actual mass of precipitate is 4.00g, calculate the percent error of this experiment.

*January 8, 2011 by Rebekah*

**Chemistry**

A student mixes 100.0 mL of 0.300 mol/L silver nitrate solution with 100.0 mL of 0.300 mol/L calcium chloride solution. a) Determine the theoretical yield of the precipitate. b) If the actual mass of precipitate is 4.00g, calculate the percent error of this experiment.

*January 8, 2011 by Rebekah*

**Chemistry **

One half-cell in a voltaic cell is constructed from a silver wire electrode in a .25 M solution of AgNO3 . The other half-cell consists of a zinc electrode in a .001 M solution of Zn(NO3)2. Calculate the cell potential I have no idea and am so stressed, Help please

*November 18, 2015 by Anonymous *

**Chemistry**

The cell Pt|H2(1 bar)|HCl(m)|AgCl(s)|Ag has an Stadard elctrode potential value of 0.2224V at 298K Using the Nernst equation, calculate a value for the EMF when the HCl concentration is 0.20M. I know what the Nernst equation is but I am unsure how to use it when I only have ...

*January 14, 2009 by Alice*

**chemistry**

When 0.752 g of Ca metal is added to 200.0 mL of 0.500 M HCl(aq), a temperature increase of 12.2C is observed. Assume the solution's final volume is 200.0 mL, the density is 1.00 g/mL, and the heat capacity is 4.184 J/gC. (Note: Pay attention to significant figures. Do not ...

*February 9, 2007 by nickel*

**Algebra**

2. Find the value of x^3 + 2x^2 - 3 when x=3 Answer-42 4. Compare the quantity in Column A with the quantity in Column B. Column A Column B The solution of The solution of 2(x-3) = 6x 3x + 2 + 5x + 6

*August 7, 2011 by lizzie*

**Math help**

1. Which value is a solution of the equation 5 - 4x = -3 0 2 -3 1/4 2. Which ordered pair is a solution of the equation y = x - 4 (2, 6) (6, 2) (-2, 6) (3, -1) 3. Which ordered pair is a solution of the equation y = 3x (-2, -9) (-8, -18) (-8, -3) (-10, -30) 4. Which ordered ...

*October 15, 2013 by Charlotte*

**Chemistry**

An antacid tablet weighing 1.462 grams was dissolbed in 25mL of 0.8M HCl and diluted with water. The excess HCl was titrated with 3.5 mL of 1.019M NaOH solution. 1. Calculate the number of millimoles added to the tablet 2. Calculate the number of millimoles of NaOH required to...

*July 1, 2010 by Daria*

**Chemistry**

An antacid tablet weighing 1.462 grams was dissolbed in 25mL of 0.8M HCl and diluted with water. The excess HCl was titrated with 3.5 mL of 1.019M NaOH solution. 1. Calculate the number of millimoles added to the tablet 2. Calculate the number of millimoles of NaOH required ...

*October 4, 2010 by Jennifer *

**Chemistry**

How would you prepare 455 g of aqueous solution that is 6.50% sodium sulfate Na2SO4 by mass? percent by mass = grams/100 g solution. X grams/455 = 0.065 solve for X. Subtract 455-X to calculate how much water must be added. ok i got -454.935 is this right

*February 6, 2008 by Lauren*

**chemistry**

Two aqueous solutions of sucrose, C12H22O12, are mixed. One solution is 0.1495 M sucrose and has d = 1.018 g/mL; the other is 12.00 sucrose by mass and has d = 1.038 g/ml. Calculate the moles C12H22O12 percent in the mixed solution. Please provide steps (assume volume is same ...

*February 17, 2010 by anonymous*

**chemistry**

Two aqueous solutions of sucrose, C12H22O12, are mixed. One solution is 0.1495 M sucrose and has d = 1.018 g/mL; the other is 12.00 % sucrose by mass and has d = 1.038 g/ml. Calculate the moles C12H22O12 percent in the mixed solution. Please provide steps (assume volume is ...

*February 17, 2010 by anonymous*

**Chemistry(Please check)**

I need to calculate the valueof Kc for 5 test tubes for an experiment that I completed on determination of Kc. The equation used was Fe^3+ + SCN^-= FeSCN^2+ After creating an ice table for the first test tube my values for Fe and SCN were 6.5e-4M and for FeSCN I got 5.7e-5M. ...

*March 6, 2012 by Hannah*

**Chemistry **

How many liters of gasesous methane (CH4) must be burned in oxygen to produce enough H2O and CO2 to fill a 3.0 L balloon? Assume that H2O and CO2 are the only combustion products and that the temperature and pressure remain constant. How would I solve this? Attempt: 3.OL (1 ...

*August 29, 2010 by Amy~*

**chemistry**

Hey, I am having a real hard time getting the answers to the problems. Any help would be greatly aprreciated! 1. When 11 mL of a solution containing 2.9 M AlBr3 is diluted to 33 mL, a dilute solution is formed. What is the Br- concentration in 25 mL of the dilute solution? 2. ...

*November 7, 2007 by chelsea*

**Chemistry **

This is a longer assignment. I want you to confirm my first two answers and help me figure out the last. 3 Cu (s) + 8 HNO3 (aq) → 3 Cu(NO3)2 (aq) + 2 NO (g) + 4 H2O (l) A copper penny with a mass of 3.067 g is dissolved in 100.0 ml of 1.000 M nitric acid. A. How many ...

*January 6, 2015 by Morgan *

**math (is this worked correctly)**

given that a=4,b=-2 and c=3 Calculate the value of a^2-bc/b+c answer=22

*April 16, 2008 by Corina*

**Statistics**

How do you calculate the value of z* and t* on the TI-84 and TI-89 (the number used in confidence intervals)?

*March 30, 2010 by Bob*

**chemistry**

Calculate the value of Kc for 4NH3(g) + 3O2(g)= 2N2(g) + 6H2O(l)

*July 12, 2012 by mohamed*

**add maths**

calculate the value of log square root p p^2.

*May 3, 2014 by mandy*

**math**

calculate the value of (1 sec20¡ã cot20¡ã)(1-cosec20¡ã tan70¡ã)

*August 11, 2014 by Anonymous*

**Maths**

If 192;x;y;3 form a geometric progression, calculate the value of x and y.

*March 7, 2015 by Zikhona*

**Math**

The side of retangular floor are xm and (x + 7)m.the diagonal is (x + 8)m,calculate the value of x

*March 22, 2016 by Suraj*

**accounting**

how to calculate depreciation using carrying value method?

*April 23, 2016 by Jeylen*

**Maths**

Given that 3^9 + 3^12 + 3^15 + 3^n is a perfect cube number. Calculate the value of n.

*November 12, 2016 by Help*

**Science**

Help!! How many atoms in 3.45 mL of water? (H2O only;mL=g) and If you are out panning for gold and discover a nugget that is exactly 2.50 moles, how many molecules, atoms, and grams would you have? At a cost of $375 per ounce, what would be the value of gold?

*October 20, 2010 by Jack*

**Finance**

I need help on this study problem.----- A firm computes the probability distribution of possible net present values for a project and finds that it has an expected value of $125,000 and a standard deviation of $75,000. Assuming that the distribution of net present value is ...

*November 2, 2006 by Jenny*

**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**

Calculate the volume of 1.00 M acetic acid solution and mass of sodium acetate needed to make 250 mL of a 0.450 M acetic acid/acetate buffer solution with a pH of 4.00. (The pKa is 4.74 for acetic acid).

*November 3, 2014 by eddie*

**math **

Calculate the value of the following in exponential form, using standard scientific or "e" notation (for example, 105 = 1.05e2). Enter your answer with the correct number of significant figures. 885.75 g + 10.151 g - 25.50 g Calculate the value of the following in exponential ...

*September 23, 2010 by help?*

**chem**

An automobile burns 65 grams of gasoline over 20 minutes. The gasoline combines with 100 grams of oxygen in this reaction, to form carbon dioxide and 47 grams of water. How much carbon dioxide is formed? do I use the heat capacity equation? How much oxyen is used to produce 47...

*February 14, 2007 by tina*

**Chemistry**

Calculate the volume of 1.00 M acetic acid solution and mass of sodium acetate needed to make 250 mL of a 0.450 M acetic acid/acetate buffer solution with a pH of 4.00. (The pKa is 4.74 for acetic acid) *Please explain it in detail, don't leave a step out! Thank You!

*November 3, 2014 by Joseph*

**statistics**

The selling of prices Of six second hand bicycles in relation to their ages were noted for advertisements appearing in a local newspaper . The details are given in the table bellow. Age x ( years) 4 10 2 1 3 4 Price, y. 9 1 14 18 12 7 ( a) calculate the value of the product - ...

*August 23, 2014 by blessed*

**Chem**

4 NH3 + 3 O2 --> 2 N2 + 6 H2O a.) Assume 3.0 mol O2 completely reacts. Calculate the moles required for the other reactant. Calculate the moles that can be produced for each product. b.) Assume 8.0 mol NH3 completely reacts. Calculate the moles required for the other ...

*February 13, 2016 by Deni*

**chemistry**

For the equilibrium H2(g)+CO2(g)<-->H2O(g)+CO(g) Kc=3.18 at 1106 K.If each of the four species was initially present at a concentration of 3.000M,Calculate the equilibrium concentration of the CO (g) at this temperature. Choices 0.844 3.268 3.844 3.460 2.156 Thanks ...

*May 9, 2010 by Andy*

**Chemistry**

The combustion reaction for benzoic acid C6H5CO2H(s) + 15 2 O2(g) → 7 CO2(g) + 3 H2O(ℓ) has ∆H0 = −3226.7 kJ/mole. Use Hess’s Law to calculate ∆H0 f for benzoic acid.

*October 7, 2012 by Austin*

**mixture problems**

A chemist has two solutions of sulfuric acid. One is a 25% solution, and the other is a 50% solution. How many liters of each does the chemist mix to get 10 liters of a 40% solution? 25% solution L: 50% solution L:

*November 21, 2014 by Kendall*

**Chem**

Using the standardized NaOH solution, the student weighs out 0.2550g of a solid unknown acid and finds that 28.50mL of the NaOH solution is required to reach an end point with the acid. Calculate the molar mass of the unknown acid, assuming the acid is diprotic.

*April 25, 2014 by Jen*

**Chem**

Using the standardized NaOH solution, the student weighs out 0.2550g of a solid unknown acid and finds that 28.50mL of the NaOH solution is required to reach an end point with the acid. Calculate the molar mass of the unknown acid, assuming the acid is diprotic.

*April 25, 2014 by Jen*

**SAT Math**

Can I please get some help on these questions: 1. If , find the value of 2 square root of 17-x = 2x-10, find the value of x/4. 2. If absolute value of 3x+6 < 9, then which of the following is a possible value of x ? My answer choices are -7, 1, -5, -1, 10. When I solve for ...

*June 1, 2013 by mysterychicken*

**maths**

the value of a car depreciate by 13% of it value in the first year. in the subsequent year the depreciation is 8% of its value at the beginning of the year.the value of the car when new is $45000. find its value when it is four years old.

*February 21, 2016 by fernando *

**chem 1151**

a 250.0 mL of solution contains 50.0 mL acetone and 45.0 mL ethyl alcohol and the remainder water. Calculate the % acetone, % ethyl alcohol, and water in the solution. Show calculations.

*June 14, 2011 by ris*

**Chemistry**

A solution is made by dissolving 26.7 g urea, a nonelectrolyte, in 301 g water. (The vapor pressure of pure water is 23.8 torr at 25°C and 71.9 torr at 45°C.) Calculate the vapor pressure of this solution at 25°C.

*May 6, 2015 by Jack*

**Chemistry help**

I am confused as to how to solve the below problem. I am not sure which formula to use. At first I thought I calculate the molar mass of NaOH, followed by calculating moles of NaOH. But I don't have the mass of NaOH to calculate moles. Do I convert 10mL to grams to Be able to ...

*March 15, 2012 by Julie*

**Chemistry**

Can someone confirm that I'd be doing this right? If an 0.520 m aqueous solution freezes at -3.00 C, what is the van't Hoff factor, i, of the solute? It says I can find the Kf values on a table. I had no idea which Kf value to use... so i just used water... is that right? If ...

*February 16, 2012 by David*