Saturday
September 5, 2015

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

chemistry
How many grams of H2 are needed to produce 12.22g of NH3?
Thursday, April 2, 2015 by Branson

Chemistry
I am trying to solve a buffer problem. I know I need to use the Henderson-Hasselblach equation but I am not getting the correct answer. The problem is: Propionic acid is a weak monoprotic acid with Ka = 1.3×10-5 M. NaOH(s) was gradually added to 1.00 L of 1.29×10-2...
Thursday, April 2, 2015 by Cara

Chemistry
Calculate the value of ΔS when 1.10mol of Br2(l) is vaporized at 58.8 ∘C
Thursday, April 2, 2015 by Austin

Chemistry
When 85g of CH4 are mixed with 85g of O2 according to this equation: CH4 + 2O2 - cO2 + 2H2O What is the theoretical yield in gams of CO2? What is the percent yield if 45.7g of CO2 are produced? Please explain!
Thursday, April 2, 2015 by Pria

Chemistry
the rate of diffusion of a gas having molecular weight just double of hydrogen gas is 30 ml/s.the rate of diffusion of hydrogen gas will be
Thursday, April 2, 2015 by Tanya

Chemistry
What is a balanced equation for a Base-Acid Titration?
Thursday, April 2, 2015 by Madison

chemistry
17. Calculate H for the following reaction using Hess law H2 (g) + Br2 (g) → 2 HBr (g) Experimental information 2 H+ → H2 H -436.4 kJ 2 Br- → Br2 H -192.5 kJ 2 H+ + 2 Br- →2 HBr H -144.8 kJ
Thursday, April 2, 2015 by john

Chemistry
Why can't milk of magnesia (Mg(OH)2), act as a buffer?
Thursday, April 2, 2015 by Michelle

Chemistry
The ph of a solution is 9.55 at 25degree celcius. What is the hydroxide-ion in the solution?
Thursday, April 2, 2015 by Sophie

Chemistry
For the reaction 4FeCl2(aq) + 3O2(g) - 2Fe2O3(s) + 4Cl2(g); how many grams of FeO3 are produced from 8.71 x 10 to the 21st power molecules of O2?? Help Please!
Thursday, April 2, 2015 by Pria

chemistry
Why do you add Sodium hydroxidein your reduction procedure
Thursday, April 2, 2015 by mino

chemistry
assuming only glassware was supplied for the original experiment, what would be the procedural change necessary to titrate 25.00mL of commercial bleaching solution.
Thursday, April 2, 2015 by gladys

chemistry
You weigh out an antacid tablet and determine the mass to be 1.1990 g. After taking a 0.2455 g sample of the antacid tablet, you dissolve it in 25.00 mL of a 0.1006 M solution of hydrochloric acid in a 250.0 mL Erlenmeyer flask. After heating the solution to get rid of carbon ...
Thursday, April 2, 2015 by zee

chemistry
What is the heat involved when 3.00 g of aluminum oxide is formed?
Thursday, April 2, 2015 by Kodi

chemistry
calculate the grams of 1.8% (m/m) NaCl solution that contains 8.00 g of NaCl I tried 1.8 times 8.00g divided by 58.44g times 100 my answer is 24.6g rounded to 2 SF is 25g this truned out to be wrong I'm stumped!
Wednesday, April 1, 2015 by k

chemistry
calculate delta G at 298 K when 5.0 atm H2 and 3.0 atm of CO2 are converted to methanol.
Wednesday, April 1, 2015 by Yvonne

Chemistry
How many moles of HNO3 are present if 0.116mol of Ba(OH)2 was needed to neutralize the acid solution?
Wednesday, April 1, 2015 by Mac

chemistry
Aqueous hydrobromic acid will react with solid sodium hydroxide to produce aqueous sodium bromide and liquid water . Suppose 4.05 g of hydrobromic acid is mixed with 0.86 g of sodium hydroxide. Calculate the maximum mass of water that could be produced by the chemical reaction...
Wednesday, April 1, 2015 by Anonymous

Chemistry
High concentration of iron (III) ions, Fe3+, cause hard water. Write a balanced equation to show how iron ions can be removed using sodium carbonate, NaCO3.
Wednesday, April 1, 2015 by sharon

chemistry
A 1.0 x 10-2 M solution of a weak acid is found to be 3.7% dissociated. Calculate Ka of this acid. I found the amount dissociated by (amount dissociated/initial conc)*100=3.7 Where do I go from here?
Wednesday, April 1, 2015 by Mahnoor

Chemistry
What would be the procedure for titrating a beverage to determine the concemtration of weak acid? What reagents would be needed? What appropiate measurements and observations must be made?
Wednesday, April 1, 2015 by Anonymous

chemistry help
a 3.54 grams solid sample of an unknown monoprotic acid was dissolved in distilled water to produce a 47.0 mL solution at 25 degrees. This solution was then titrated with 0.2 M NaOH. The equivalence point was reached when 35.72 mL of 0.2 M NaOH was delivered. A. find the ...
Wednesday, April 1, 2015 by jk

chemistry help
In the following questions, assume that no excess distilled water was added from a wash bottle during the titration of 10.00 mL of vinegar with your standardized solution of NaOH. A. calculate the pH of vinegar. B. what was the pH of the solution after 4.00 mL of titrant was ...
Wednesday, April 1, 2015 by jk

chemistry help
A 15.00 mL sample of an unknown monoprotic weak acid solution is titrated with 0.35 M NaOH. The initial buret reading is 0.23 mL. The phenolphthalein indicator turns the solution light pink when the buret reads 29.58 mL. B. How many moles of NaOH were delivered? C. How many ...
Wednesday, April 1, 2015 by jk

Chemistry
The chemical equation for ionic reaction between Na2S and AgNO3??
Wednesday, April 1, 2015 by Angie

Chemistry
How many moles of H2O are in 12.7 grams of H2O?
Wednesday, April 1, 2015 by Andrew

Chemistry
how many grams of Nano3 are in 0.755 moles of nano3
Wednesday, April 1, 2015 by Steven

Chemistry
how many grams of sugar would be needed to give a 50.00 mL solution of FD&C Red Dye a concentration of 6.0% sugar?
Wednesday, April 1, 2015 by Capria F.

chemistry
calculate delta G at 298 K when 5.0 atm H2 and 3.0 atm of CO2 are converted to methanol. I know you can calulate for Q and use that but how do you do the calculation when you dont have the atm for the final product.
Wednesday, April 1, 2015 by Yvonne

chemistry
calculate the change in pH when 5 ml of 0.01M HNO3 is added to 50 ml of water. I know how to calculate pH, but not when it is changing.
Wednesday, April 1, 2015 by Yvonne

chemistry
Calculate the molarity of a solution made by adding 47.2g of NaNO3 to a flask and dissolving it with water to create a total volume of 1.80L .
Wednesday, April 1, 2015 by Sam

chemistry
How many grams of sucrose (C12H22O11) are in 2.50L of 0.710M sucrose solution?
Wednesday, April 1, 2015 by Samantha

Chemistry
A student generated oxygen gas by decomposing hydrogen peroxide (H2O2) according to the following equation: 2H2O2(aq) -> 2H2O(l) + O2(g) If the student started with 1.75 moles of hydrogen peroxide, how many moles of oxygen gas would be produced? Show your work. ((If you can...
Wednesday, April 1, 2015 by Emily

Chemistry
how many grams of KCIO3 can be dissolved it 50 g h20 at 50 degrees celcuis?
Wednesday, April 1, 2015 by Linda

chemistry
In the following questions, assume that no excess distilled water was added from a wash bottle during the titration of 10.00 mL of vinegar with your standardized solution of NaOH. A. calculate the pH of vinegar. B. what was the pH of the solution after 4.00 mL of titrant was ...
Wednesday, April 1, 2015 by jk

chemistry
A 15.00 mL sample of an unknown monoprotic weak acid solution is titrated with 0.35 M NaOH. The initial buret reading is 0.23 mL. The phenolphthalein indicator turns the solution light pink when the buret reads 29.58 mL. A. what volume of 0.35 M NaOH was delivered? B. How many...
Wednesday, April 1, 2015 by jk

chemistry
a 3.54 grams solid sample of an unknown monoprotic acid was dissolved in distilled water to produce a 47.0 mL solution at 25 degrees. This solution was then titrated with 0.2 M NaOH. The equivalence point was reached when 35.72 mL of 0.2 M NaOH was delivered. A. find the ...
Wednesday, April 1, 2015 by jk

chemistry
the complete electrolysis of 90 grams of water will yield
Wednesday, April 1, 2015 by seyimichael

chemistry
0.1 mol of an organic acid is added to 600 ml of 0.5M KOH solution. The resulting basic solution can be neutralized by 200 ml of 0.5 M HCl solution. Which acid is ot?
Wednesday, April 1, 2015 by lalala

chemistry
At a certain elevation, the boiling point of water is 98.5°C. How much energy is needed to heat 35.0 mL of water to the boiling point at this elevation if the water initially was at 23.4°C? (Cp=75.38J/(mol*C), d= 1.00g/mL)
Wednesday, April 1, 2015 by Danny

chemistry
how to prepare 1 L of 2.5M nitric acid from 69% of concentrated nitric acid?
Wednesday, April 1, 2015 by epis

chemistry
You find the Ka of your unknown acid is 6.3x10 -5 . If you are being asked to make a buffer at pH 4.00, what is the appropriate ratio of A- to HA to be combined in your flask?
Tuesday, March 31, 2015 by anon

chemistry
You measure the pH of a 0.50 M unknown acid solution using a pH meter and it is found to be 1.74. What is Ka for the acid? I know ph=-log{H+} Where do I go from here?
Tuesday, March 31, 2015 by anon

Chemistry physics
3.25x10-3 kg of gold is deposited onto the negative electrode of an electrolytic cell in a period of 2.78 hours, what is the current through this cell in amperes? Assume that the gold ions carry one elementary unit of charge
Tuesday, March 31, 2015 by Bill

chemistry to MathMate
Chemistry - CJ, Tuesday, March 31, 2015 at 10:53pm I am experiencing a major block.... I can't say.... 1micrometer= 1000nm 5micrometer= x..... because I'll get back the same thing So please help me, tell me the answer please.
Tuesday, March 31, 2015 by CJ

physical chemistry
I need to make a solution of 50% ethanol in water (by mass). The partial molar volume of water is 17.0mL/mol and the partial molar volume of ethanol is 52.0mL/mol. What is the density of this solution/
Tuesday, March 31, 2015 by chimuka

Chemistry
Write a balanced equation for the combustion of gaseous ethylene (C2H4), an important natural plant hormone, in which it combines with gaseous oxygen to form gaseous carbon dioxide and gaseous water
Tuesday, March 31, 2015 by Samantha

chemistry
How many ml of molar sulfuric acid is to be added to 50.0 ml of 0.250 molar sodium hydroxide solution to neutralize it completely . cannot post reaction sorry ..
Tuesday, March 31, 2015 by laura

Chemistry
56mL of a stock solution of hydrobromic acid, HBr, is added to 85mL of water, yielding a solution having a pH of 1.0. What was the molarity of the stock solution? I know Molarity = moles of solute/ liters of solution
Tuesday, March 31, 2015 by Danielle

AP Exams?
I am in AP Chemistry and AP U.S Hisotry and I have planned on taking the tests. So far I have made an A+ in APUSH, but I an B in AP Chem. I've done kinda bad on the tests I've taken in there and I don't think I will do good on the Ap exam. I think I have a better ...
Tuesday, March 31, 2015 by Anonymous

Chemistry DrBob please answer
A reaction at 3.24 atm consumes 5.10 L of a gas adiabatically (q = 0). Calculate the change in internal energy of the system (in kJ). I know that I have to use w=-p deltaV but how do i find the Final and Initial volumes?
Tuesday, March 31, 2015 by JUNDY

Chemistry
Chemistry - MathMate, Tuesday, March 31, 2015 at 2:56pm 1m = 1000 mm (millimeter) 1 mm = 1000 μm (micrometer) 1 μ = 1000 nm (nanometer) If the tube is 1 nm in diameter, then veryify that 5 μm = 5*1000 nm = 5000 nm = how many diameters? Chemistry - MathMate, ...
Tuesday, March 31, 2015 by CJ

Chemistry
A reaction at 3.24 atm consumes 5.10 L of a gas adiabatically (q = 0). Calculate the change in internal energy of the system (in kJ). I know that I have to use w=-p deltaV but how do i find the Final and Initial volumes?
Tuesday, March 31, 2015 by JUNDY

Chemistry
Calculate the change in entropy (in J/K) when 61.4 g of nitrogen gas is heated at a constant pressure of 1.50 atm from 25.8 ºC to 92.8 ºC. (The molar specific heats are Cv is 20.8 J/(mol-K) and Cp is 29.1 J/(mol-K) .)
Tuesday, March 31, 2015 by June

Chemistry
Calculate the change in entropy (in J/K) when 86.4 g of water is heated from 17.5 ºC to 76.5 ºC at 1 atm. (The specific heat is 4.184 J/(g-K).)
Tuesday, March 31, 2015 by Emily Couroso

Chemistry
Calculate the increase of entropy (in J/K) when 75 g of ice melts at 0 ºC and 1 atm. (The heat of fusion for ice is 6,000 J/mol.)
Tuesday, March 31, 2015 by Emily Couroso

Chemistry
Using the technique of the previous problem ΔE was found to be -2,000.00 kJ/mol of an unknown liquid hydrocarbon at 298 K. In another experiment it was determined that for each mole of hydrocarbon, 4 moles of oxygen gas are consumed and 6 moles of CO2 gas and 6 moles of ...
Tuesday, March 31, 2015 by John Handra

Chemistry
1.578 g of an unknown hydrocarbon (110.7 g/mol) burns in bomb calorimeter in excess oxygen. The heat capacity of the calorimeter,Cv, = 5.709 kJ/ºC and ΔT =7.995 ºC. Find ΔE for this hydrocarbon in kJ/mol.
Tuesday, March 31, 2015 by JUNDY

Chemistry
A reaction at 3.24 atm consumes 5.10 L of a gas adiabatically (q = 0). Calculate the change in internal energy of the system (in kJ).
Tuesday, March 31, 2015 by JUNDY

Chemistry
A reaction at 2.43 atm produces 20.0 L of a gas and evolves 75.3 kJ of heat (exothermic). Calculate the change in internal energy of the system (in kJ).
Tuesday, March 31, 2015 by JUNDY

chemistry
If one pound (454g) of hexane combusts how many grams of water are produced? How do u set this up? Start it?
Tuesday, March 31, 2015 by sarah

chemistry
How many grams of CO2 are produced when 11.47 moles hexane combust? Show work please
Tuesday, March 31, 2015 by sarah

Chemistry
Nanotubes are rolled up cylinders of graphite with diameters of about 1nanometer, and lengths in micrometers. (I) If a nanotube is 5 micrometers long, how many diameters does this represent?
Tuesday, March 31, 2015 by CJ

chemistry
How much carbon dioxide measured at 25.0◦C and 821 Torr would be produced by the combustion of 319 g of glucose (C6H12O6)? 1. 40.1 L 2. 20.2 L 3. 241 L 4. 3.37 L
Tuesday, March 31, 2015 by Evelyn

Chemistry
16. From the standard enthalpies of formation, calculate the Horxn for the reaction: (Hof = -151.9 kJ/mol for C6H12.) C6H12(l) + 9 O2(g)  6 CO2 (g) + 6 H2O(l)
Tuesday, March 31, 2015 by nona

chemistry
4.90 gram of KCLO3 is heated. it shows a weight loss of 0.384 gram . what is he percent of original KCLO3 which has decomposed .
Tuesday, March 31, 2015 by shubham

Chemistry
A 0.3423 g sample of pentane, C5H12, was burned in a bomb calorimeter. The temperature of the calorimeter and the 1.000 kg of water contained therein rose from 20.22°C to 22.82°C. The heat capacity of the calorimeter is 2.21 kJ/°C. The heat capacity of water = 4....
Tuesday, March 31, 2015 by Cassandra

Chemistry
What would be the consequence of competing equilibria, such as from other ingredients in an aspirin tablet in a titration lab results? What if there were several pain relievers in the same tablet? How could the error from these interferences be minimized?
Tuesday, March 31, 2015 by Anonymous

chemistry
What is the volume occupied by 20.9g of argon gas at a pressure of 1.09atm and a temperature of 411K ?
Monday, March 30, 2015 by Famata

Chemistry
how many molecules of N2 could fit in a 2.00L soda bottle at 23C and 755mmHg
Monday, March 30, 2015 by Stephen

Chemistry
A jar contains 75mL of a .45M silver nitrate solution. Will 200g of solid copper be enough to bring all the silver out of solution as a solid?
Monday, March 30, 2015 by Michelle

Chemistry
Table salt, NaCl(s), and sugar, C12H22O11(s), are accidentally mixed. A 4.00-g sample is burned, and 2.70 g of CO2(g) is produced. What was the mass percentage of the table salt in the mixture?
Monday, March 30, 2015 by Sarah

chemistry
Propane fuel is used in BBQs. Use the following reaction to determine how many moles of oxygen gas are needed to react with 1.6 moles of propane gas. C3H8(g)+5O2(g) --------> 4H2O(g)+ 3CO2(g)
Monday, March 30, 2015 by stacy

chemistry
I'm confused on number 6 on the take home test. in this problem are we going to use the heat capacity of calorimeter is 2.21kJ/c. I'm confused on how to set this problem up 1)I converted 1.000kg in to grams= 1000g 2) I used q=m*c* the change in T 1000g*(4.184J/g* C)*(...
Monday, March 30, 2015 by Cassandra

chemistry
A chunk of silver has a heat capacity of 42.8 j/°c and a mass of 181 g. Calculate the specific heat of silver
Monday, March 30, 2015 by jamiaya bailey

Chemistry
Given that Ka for HIO is 3.2 × 10-11 at 25 °C, what is the value of Kb for IO– at 25 °C? Then, Given that Kb for C6H5NH2 is 1.7 × 10-9 at 25 °C, what is the value of Ka for C6H5NH3 at 25 °C? I don't know where to start? Do I need an ICE ...
Monday, March 30, 2015 by Michelle

chemistry
is trans-dibromoethene a proper way of labeling an alkene?
Monday, March 30, 2015 by Anonymous

chemistry
n2+3I2>2NI3 if you have 28g of N2how many grams of NI3 will you be able to make?
Monday, March 30, 2015 by Nicole

Chemistry
Calculate the solubility of silver chloride in a solution that is .170M in NH3
Monday, March 30, 2015 by Gabby

chemistry
Calculate the pH of the buffer system after the addition of 0.1 mol of gaseous HCl of the solution. Assume that the volume of the solution does not change when the HCl is added.
Monday, March 30, 2015 by zayde

chemistry
how much NaNO3 must be added to saturate 100.0 grams of water at 20 degrees
Monday, March 30, 2015 by Victoria

Chemistry
heat of combustion of propane c3h8, 2220KJ/mol. the specific heat of copper is 0.385 J/g*C. How many grams of propane must be burned to raise the temperature of a 10.0kg block of copper from 25.0 C to 65.0 C,assuming none of the heat is lost to the surroundings I'm stuck ...
Monday, March 30, 2015 by Cassandra

chemistry
What volume of oxygen(in Liters) at 25 degrees C and 1.05 atm is needed to completely combust 2.65L of methane, measured at STP
Monday, March 30, 2015 by lina

chemistry help
What mass of ammonium chloride must be added to a 0.500 L solution of 0.250 M ammonia to make a buffer with a pH of 9.26? Kb (NH3) = 1.8 × 10–5?
Monday, March 30, 2015 by paula

physical chemistry
calculate late the Gibbs free energy, entropy and enthalpy of mixing when 500g of heptane is mixed with 500g oh hexane at 298K.
Monday, March 30, 2015 by pholisa

AP Chemistry
A 5.0 M solution of HNO3 is titrated with 0.3 M NaOH. Identify the species that have the highest concenttrations in the solution being titrated halfway to the equivalence point. A 25.15 ml of 0.35 m HNO3 was titrated with an unknown concentration of NaOH. The endpoint was ...
Sunday, March 29, 2015 by Sara

chemistry
what would be the final concentration if you incorporate 11m: of 29'' concentration of HF to 800mL of water?
Sunday, March 29, 2015 by camille

chemistry
Determine the limiting reactant for this reaction if 3.027 grams of Aluminum are reacted with 60.00 mL of a solution that is 6 M KOH. Determine the amount of KAl(SO4)2•12 H2O that can be produced from this reaction. Molar mass Alum = 474 g/mol 2 Al (s) + 2 KOH (aq) + 22 ...
Sunday, March 29, 2015 by Jonathan

Chemistry
You have 100 mL of a 0.450 M sulfuric acid solution, but you now need to add NaOH to make the solution basic. How much NaOH ( in grams) will you need to add to make the solution have a pH of 13.0? The units are grams of NaOH.
Sunday, March 29, 2015 by Tessa Lehan

chemistry
What is the total change in entropy when 10.0 g of ice melts at 25.0°C? DHfus = 6.01 kJ/mol The answer is 1.03 J/K but idk how to find it.
Sunday, March 29, 2015 by paula

chemistry
calculate the pH after 0.02 mol NaOH is added to 1.00 L of .1 M sodium propanoate NaC3H5O2
Sunday, March 29, 2015 by jk

Chemistry
a gas is placed in a 3.56L flask at 1.00 atm pressure. If the volume of the flask is reduced by half, what is the new pressure? V-3.56 P-1.00 I don't know what formula to use and how to apply it.
Sunday, March 29, 2015 by Ann

Chemistry
Sulfuric acid dissolves aluminum metal according to the following reaction: 2Al(s)+3H2SO4(aq)→Al2(SO4)3(aq)+3H​2(g) Suppose you wanted to dissolve an aluminum block with a mass of 14.5g . 1.) What minimum mass of H2SO4 would you need? 2.)What mass of H2 gas would ...
Sunday, March 29, 2015 by Katie

Chemistry
A helium-filled balloon has a volume of 2.68 L at 15◦C. The volume of the balloon decreases to 2.33 L after it is placed outside on a cold day. What is the outside temperature in K? Answer in units of K.
Sunday, March 29, 2015 by Maggie

chemistry
what is the delta Hvap of a liquid that has a vapor pressure of 612 torr at 77.6 degrees C and a boiling point of 94.9 degrees C at 1 atm
Sunday, March 29, 2015 by kim

Chemistry help
A gas occupying 29 mL at standard conditions is heated to 14◦C while the pressure is reduced to 0.98682 atm. What is the new volume occupied by the gas?
Sunday, March 29, 2015 by Quintin

Chemistry
For the substance SO2F2(g), ΔHºf = -858 kJ mol-1 and the S-F bond, 308.0 kJ mol-1 Determine the average S=O bond energy in SO2F2 in units of kJ. Is my answer right, if so how do I convert this to kJ? x= S=O bond -858= 2(308) + 2(x) -737kJ/mol
Sunday, March 29, 2015 by Nicky

Chemistry
A 1.0-g sample of MgCl2 produced a 10.00C increase in a calorimeter charged with 40.0mL of deionized water. The specific heat is of MgCl2 is 0.750J/C*g. What is the value of delta(s)H for MgCl2? I know that the formula needed is delta(s)H=-([massH2O*deltaTH20]+[mass(Mg​...
Sunday, March 29, 2015 by MB

Pre Ap Chemistry
A sample of carbon dioxide gas occupies 566 mL at 0.825 atm and 15 ◦C. What will the pressure be at a volume of 834 mL and a temperature of 20◦C
Sunday, March 29, 2015 by Analyse

Chemistry
What pressure is required to reduce 34 mL of a gas at standard conditions to 16 mL at a temperature of 20◦C
Sunday, March 29, 2015 by Emily

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