Friday
May 24, 2013

# Homework Help: Science: Chemistry

Chemistry
Suppose it is a hot summer day (40.0 degrees C = 104.0 degrees F), and you have left a can of hairspray outside so the gas within it is now at the same temperature of its surroundings. As part of your chemistry lab class, you have to build a safe and effective potato gun to ...
Saturday, March 16, 2013 at 7:52pm

Chemistry
Suppose it is a hot summer day (40.0 degrees C = 104.0 degrees F), and you have left a can of hairspray outside so the gas within it is now at the same temperature of its surroundings. As part of your chemistry lab class, you have to build a safe and effective potato gun to ...
Saturday, March 16, 2013 at 7:51pm

Chemistry
So, I go to high school in Texas and we have this AP Chem lab due online tomorrow night by midnight and I need some serious help on these questions:  Lab Temp 0.2°C  Experiment Trial Time in seconds Trial 1 Trial 2 Average Time  1 1 2 256 275 268  ...
Saturday, March 16, 2013 at 6:51pm

Chemistry AP
It was determined that a 0.10 M solution of an acid was only 2.5% ionkzed. Find the Ka and pKa for the acid.
Saturday, March 16, 2013 at 5:59pm

Chemistry
At 22 °C an excess amount of a generic metal hydroxide M(OH)2, is mixed with pure water. The resulting equilibrium solution has a pH of 10.49. What is the Ksp of the salt at 22 °C?
Saturday, March 16, 2013 at 4:53pm

Chemistry
Sodium sulfate is slowly added to a solution containing 0.0500 M Ca^2+ (aq) and 0.0390 M Ag^+ (aq). What will be the concentration of Ca^2+ (aq) when Ag2SO4(s) begins to precipitate? What percentage of the Ca^2+ (aq) can be separated from the Ag^+ (aq) by selective precipitation?
Saturday, March 16, 2013 at 4:49pm

Chemistry
The Ksp of magnesium hydroxide, Mg(OH)2, is 5.61 × 10^-12. Calculate the molar solubility of this compound. Is the answer 1.1*10^-4 M?
Saturday, March 16, 2013 at 4:46pm

Chemistry
How are a mix of pre-1982 and post-1982 pennies a misleading or incorrect analogy for actual element isotopes?
Saturday, March 16, 2013 at 3:43pm

Chemistry
Suppose you have to prepare 1.00 L of the solution ( KH2 PO4 and Na2 HPO4 pH=7.31) and that this solution must be isotonic with blood (have the same osmotic pressure as blood). What mass of KH2 PO4 would you use? b) What mass of Na2 HPO4 . 12 H2O would you use
Saturday, March 16, 2013 at 3:25pm

Chemistry
You are to prepare a KH2PO4 and Na2HPO4 solution with pH=7.31. What should the concentration of [2(HPO4) 2-] / [H2PO4-]
Saturday, March 16, 2013 at 3:20pm

Chemistry
Suppose you have to prepare 1.00 L of the solution ( KH2PO4 and Na2HPO4 pH=7.31) and that this solution must be isotonic with blood (have the same osmotic pressure as blood). What mass of KH2PO4 would you use?
Saturday, March 16, 2013 at 3:16pm

chemistry (Pls Bob check for me)
A 150mg/dl glucose solution was diluted 1:2. Then 0.5ml of it was added to 4.5ml saline. 2ml of this solution was diluted to 10ml. What is the final concentration of glucose? 1L = 10dL 1dL = 100mL My own calculation 150mg/dL = 150mg/100ml =1.5 150mg/100ml x 1/2 x 1/10 x 1/5 1....
Saturday, March 16, 2013 at 3:14pm

Chemistry
A 5.00L reaction vessel is filled with 1.00mol of H2, 1.00mol of I2, and 2.50mol of HI. If equilibrium constant for the reaction is 129 at 500k, what are the equilibrium concentrations of all species? H2(g) + I2(g) <-> 2HI(g) Kc = 129
Saturday, March 16, 2013 at 2:38pm

chemistry (Pls Bob check for me)
A 150 mg/dl glucose solution was diluted 1:2. Then 0.5ml of it was added to 4.5ml saline 2 ml of this solution was diluted to 10ml. What is the final concentration of glucose? 1L= 10dl 1dl =100mL Answer 0.015mg/dl
Saturday, March 16, 2013 at 2:30pm

Chemistry
0.194M NaOH and 0.268 M NH4CL Find concentration of OH
Saturday, March 16, 2013 at 1:04pm

Chemistry
Hydrocinnamoyl chloride + AlCl3 --> ??
Saturday, March 16, 2013 at 11:20am

Chemistry
0.25mol of CO are mixed with 0.90mol of H2 and heated to 950 degrees celcius in a 15L flask at equilibrium 0.190mol of H2O were present, what is the concentration of the other reactants and products at equilibrium and what is Kc
Saturday, March 16, 2013 at 10:45am

Chemistry
For calculating the concentration of a metal Ion in Equilibrium with a complex ion...how do I get the right hand side of this equation to equal 5.9 E -8? x(0.98 + 2x)2 _____________ = 1.7 E 7 (0.010-x) then, x(0.98)2 ________ = 5.9 E -8 0.010 I understand that you cancel out ...
Saturday, March 16, 2013 at 9:46am

chemistry
0.315 M 2(NH4)SO4 and 0.488 M NH3 Calculate concentration of OH
Saturday, March 16, 2013 at 3:41am

chemistry
What is the amount of H2O that can be produced by combining 89.7 of each reactant in the following equation: 4NH3(g) + 5O2 (g)----> 4NO(g) + 6 H2O(g)
Friday, March 15, 2013 at 7:24pm

chemistry
Calculate the concentrations of all species in a 0.690 M Na2SO3 (sodium sulfite) solution. The ionization constants for sulfurous acid are Ka1 = 1.4× 10–2 and Ka2 = 6.3× 10–8.
Friday, March 15, 2013 at 6:51pm

Chemistry
The specfic heat of iron is 0.11cal/g C. The heat of fusion of iron, the heat required to convert iron from a solid to liquid at its melting point, is 63.7cal/g. Iron melts at 1530 C. How much heat must be added to 2g of iron at 25c to completely melt it?
Friday, March 15, 2013 at 6:24pm

chemistry
a 225.0g sample of an unknown, silver, pure metal was heated to 95.5 degrees Celsius and then put into 150.50g of water at 22.5 degree Celsius. the water was heated by the hot metal to a temp. of 31.4 degree Celsius. what is the specific heat of the metal and what is the metal?
Friday, March 15, 2013 at 2:56pm

chemistry
How do you sole this problem: how many grams of CaCl2 are needed to prepare 7.25 L of .015M solution?
Friday, March 15, 2013 at 1:30pm

chemistry
what mass of a sample of gold requires 1.75 kJ to change its temperature from 28.2 degrees Celsius to 89.5 degrees Celsius?
Friday, March 15, 2013 at 1:22pm

Chemistry
4.34 = 0.391^2 / 0.125 / [SO2]^2 What is the concentration of SO2?
Friday, March 15, 2013 at 12:55pm

Chemistry
2A(aq)-> B(aq) +C(aq) Initial concentration of A and B is 1.00 M, with no C. Kc = 0.200 find equilibrium concentrations
Friday, March 15, 2013 at 11:47am

Science (chemistry)
Pls help.. Q: prepare a table of value for acid-base titration using 26.40cm^3 as end point
Friday, March 15, 2013 at 6:19am

chemistry
draw the conformational structures is 2-methylpentane?
Friday, March 15, 2013 at 5:44am

chemistry
what is the IUPAC name for CH3CH2C(CH3)2CH2CH(CH3)2?
Friday, March 15, 2013 at 5:41am

Chemistry
How many grams of methanol could be vaporized by the addition of 22.45kJ of heat?
Friday, March 15, 2013 at 2:19am

Chemistry
At the equivalence point in a titration you know the volume (x mL) of a standard solution of acid (2.5 M) that has been added to a known volume base (y mL). show how you can determine the concentration of the base.? Explain
Friday, March 15, 2013 at 2:09am

Chemistry
Solid Na2SO4 is added to a solution which is 0.012 M in Pb(NO3)2 and 0.048 M in AgNO3. Assume the volume remains constant. Ksp = 2.0 10-8 for PbSO4 and Ksp = 1.2 10-5 for Ag2SO4. (a) Which compound precipitates first? (b) What is the concentration of the first ion precipitated...
Friday, March 15, 2013 at 12:02am

Chemistry
Solid Na2SO4 is added to a solution which is 0.020 M in Pb(NO3)2 and 0.045 M in AgNO3. Assume the volume remains constant. Ksp = 2.0 10-8 for PbSO4 and Ksp = 1.2 10-5 for Ag2SO4. What is the concentration of the first ion precipitated when the second ion starts to precipitate?
Thursday, March 14, 2013 at 11:57pm

Chemistry
If 18.7 mL of 0.14 M MgCl2 are mixed with 24.2 mL of 0.52 M NaOH, what will be the final concentration of Mg2+ in solution when equilibrium is established? Assume the volumes are additive. Ksp = 1.2 10-11 for Mg(OH)2.
Thursday, March 14, 2013 at 11:38pm

Chemistry
Which of the following will be more soluble in an acidic solution than in pure water? Be(OH)2 Ag2SO4 RbClO4 CuCN Cul
Thursday, March 14, 2013 at 11:26pm

Chemistry
A solution is 5.0× 10–5 M in each of these ions: Ag , SO42–, Cl–, CO32– Which precipitate will form? Ag2SO4 (Ksp = 1.12× 10–5) AgCl (Ksp = 1.77× 10–10) Ag2CO3 (Ksp = 8.46× 10–12)
Thursday, March 14, 2013 at 11:18pm

Chemistry
What concentration of SO32– is in equilibrium with Ag2SO3(s) and 3.20 × 10-3 M Ag ? The Ksp of Ag2SO3=1.50×10^–14 The ksp expression is 1.50×10^-14=(Ag^+2)^2(SO3^-2)/(Ag2​SO3). Is the concentration 3.0×10^-9?
Thursday, March 14, 2013 at 11:07pm

Chemistry
A saturated solution of Mg(OH)2 is prepared having a large excess of Mg(OH)2. Sn(NO3)2 is added to the solution. Ksp = 1.8 10-11 for Mg(OH)2 and Ksp = 5.1 10-26 for Sn(OH)2. (a) What [Sn2+] is required to start the precipitation of Sn(OH)2? (b) What [Sn2+] is required so that ...
Thursday, March 14, 2013 at 10:19pm

Chemistry
If 11.6 mL of 0.17 M MgCl2 are mixed with 24.9 mL of 0.58 M NaOH, what will be the final concentration of Mg2+ in solution when equilibrium is established? Assume the volumes are additive. Ksp = 1.2 10-11 for Mg(OH)2
Thursday, March 14, 2013 at 10:16pm

CHEMISTRY: URGENT DRBob222
Why was the reaction mixture titrated quickly? (question fom: A mixture of 0.50 mol of ethanoic acid and 1.00 mol of ethanol was shaken for a long time to reach equilibrium. The whole mixture was titrated quickly with 1.00 mol dm3 sodium hydroxide and 80cm3 of alkali were ...
Thursday, March 14, 2013 at 8:45pm

chemistry
When 25.0 mL of 1.0 M H2SO4 is added to 50.0 mL of 1.0 M NaOH at 25.0 °C in a calorimeter, the temperature of the aqueous solution increases to 33.9 °C. Assuming the specific heat of the solution is 4.18 J/(g·°C), that its density is 1.00 g/mL, and that the ...
Thursday, March 14, 2013 at 7:57pm

Chemistry
A compound containing only carbon, hydrogen and oxygen is subjected to elemental analysis. Upon complete combustion, a .1804g sample of the compound produced .3051g of CO2 and .1249g of H2O. What is the empirical formula of the compound?
Thursday, March 14, 2013 at 7:16pm

Chemistry
What is the wavelength of an electron traveling at 7.59% of the speed of light?
Thursday, March 14, 2013 at 7:14pm

Chemistry
How many valance electrons are there in [(C2H5)4N]+ ?
Thursday, March 14, 2013 at 7:13pm

Chemistry
What is the C-C-H bond angle in the molecule H2CCO?
Thursday, March 14, 2013 at 7:13pm

Chemistry
What type of reaction will occur when an aqueous solution of lithium chloride is mixed with an aqueous solution of ammonium sulfate?
Thursday, March 14, 2013 at 7:11pm

Chemistry
If the molality of a CaCl2 solution is .100 mol/kg, and was made from 500.0 mL of water, how many grams of CaCl2 were needed to make the solution? Step by step would be appreciated!
Thursday, March 14, 2013 at 6:48pm

chemistry
A sample of chlorine gas is collected by water displacement at 23C. If the atmospheric pressure is 751 torr, what is the partial pressure due to the chlorine?
Thursday, March 14, 2013 at 6:40pm

CHEMISTRY: URGENT DRBob222
A mixture of 0.50 mol of ethanoic acid and 1.00 mol of ethanol was shaken for a long time to reach equilibrium. The whole mixture was titrated quickly with 1.00 mol dm3 sodium hydroxide and 80cm3 of alkali were required. 1. Write an equation for the reaction between ethanoic ...
Thursday, March 14, 2013 at 5:54pm

Chemistry
When 20.0 g C2H6 and 60.0 g O2 react to form CO2 and H2O, how many grams of water are formed?
Thursday, March 14, 2013 at 4:53pm

Chemistry
True or false? The calorie is defined as the amount of energy (heat) required to raise the temperature of one gram of water by one degree Celsius.
Thursday, March 14, 2013 at 4:32pm

Chemistry
Which of the following processes is exothermic? a.rolling a ball up a hill b.boiling water in a beaker to make steam c.allowing meat to thaw after taking it out of the freezer d.reacting hydrogen and oxygen gases to make water e.a popsicle melting on a warm summer day
Thursday, March 14, 2013 at 4:25pm

Chemistry
A 100.0 g sample of water at 27.0°C is poured into a 77.4 g sample of water at 89.0°C. What will be the final temperature of the water?
Thursday, March 14, 2013 at 4:23pm

Chemistry
An aqueous antifreeze solution is 31.0% ethylene glycol (C2H6O2) by mass. The density of the solution is 1.039 g/cm3. Calculate the molality of the ethylene glycol.
Thursday, March 14, 2013 at 3:57pm

Chemistry
An organic compound that has the empirical formula CHO has a molecular mass of 145 amu. Its molecular formula is?
Thursday, March 14, 2013 at 3:53pm

CHEMISTRY
40g of antimony combine with 80g of oxygen to form an oxide of antimony what is the simplest formula of the oxide
Thursday, March 14, 2013 at 3:17pm

Chemistry
Write a balanced equation for the following: aqueous barium chloride reacts with aqueous sodium chromate to form aqueous sodium chloride plus solid barium chromate.
Thursday, March 14, 2013 at 3:16pm

chemistry
One step in the isolation of pure rhodium metal (Rh) is the precipitation of rhodium(III) hydroxide from a solution containing rhodium(III) sulfate According to the following balanced chemical equation: Rh2(SO4)3(aq)+ 6NaOH(aq)→ 2Rh(OH)3(s)+ 3Na2SO4(aq) What is the ...
Thursday, March 14, 2013 at 3:07pm

Chemistry
A solution of hydrochloric acid (HCl) contains 22.5% hydrochloric by mass. What is the molality of this solution I'm not sure how to start this problem...
Thursday, March 14, 2013 at 3:04pm

Chemistry
If an unknown metal M is .521 g how do you calculate it's atomic mass?
Thursday, March 14, 2013 at 2:47pm

Chemistry
If an unknown metal M is .521 g how do you calculate it's atomic mass?
Thursday, March 14, 2013 at 2:47pm

Chemistry
A sample of an oxide of antimony (Sb) contained 51.5 g of antimony combined with 16.9 g of oxygen. What is the simplest formula for the oxide?
Thursday, March 14, 2013 at 2:35pm

chemistry
For the reaction 2A(g) + B(aq) + 3C(l)<------> D(s) + 3E(g), the concentrations at equilibrium are found to be: A: 2.3x10^3 Pa B: 1.8x10^-2 M C: 15.8M D: 12.5M E: 5.6x10^4 Torr i got an answer of 1.83x10^-13 is this correct??
Thursday, March 14, 2013 at 2:06pm

Chemistry Equilibrium
Which of the following conditions is always true at equilibrium? deltaG=0, Q=1, K=1, deltaG=deltaG(standard), deltaG(standard)=0, Q=0, deltaG(standard)=1 I'm so confused, please help!
Thursday, March 14, 2013 at 2:03pm

Chemistry
Rank the following compounds in order of their solubility in water. (most soluble = 1 -- least soluble = 4)--Note that for the same solubility rank the same (a tie). (CH3)2CHOH HOCH2CH(OH)CH2OH CH3CH2OH (CH3)3COH
Thursday, March 14, 2013 at 1:52pm

Chemistry
What is the molarity of nitrate ions in a solution containing 2.20 mg of Mg(NO3)2 dissolved in 7.35 L of water?
Thursday, March 14, 2013 at 1:45pm

chemistry
In a measurment 0.1M Kmno4 is used.determine the volume of solution required to react with 0.158M Na2s2o3 required?
Thursday, March 14, 2013 at 1:17pm

Chemistry
A solution has a mass of 95.00g and a density of 2.147 g/mL. What is the volume of the solution?
Thursday, March 14, 2013 at 12:06pm

Chemistry I
If 30.0 mL of 0.2 M nitric acid and 30.0 mL of 0.25 M solution of sodium hydroxide are mixed, what is the molarity of sodium nitrate? Assume that total volume of the solution after mixing is equal 60.0 mL.
Thursday, March 14, 2013 at 11:05am

chemistry
10g of silver nitrate solution is added to 10g sodium chloride solution? what change in mass do you except after the reaction and why?
Thursday, March 14, 2013 at 9:48am

Chemistry
Describe how a buffer behaves. Your description should include an explanation of why the addition of NaOH to the HAc solution formed a buffer. What happens to the pH when a small quantity of a strong acid or base is added to a buffer solution? What happens to the pH of the ...
Thursday, March 14, 2013 at 2:20am

Chemistry
48g of ice at its melting point is heated with steam at its condensation point. The final temperature of the system is 50 degree Celsius. How much steam was used to melt the ice? q=(48g)(1mol/18g)(50-0C)(0.97kcal/mol*C)​ = 129kcal Not sure where to go from here (or if ...
Thursday, March 14, 2013 at 12:38am

Chemistry
The number of moles NaOH needed to reach the equivalence point is mol, which means we must add liters of NaOH. The total volume of solution at the equivalence point will be liters. From the above information, the molarity of NaF at the equivalence point is M.
Wednesday, March 13, 2013 at 11:48pm

Chemistry
For the reaction ? FeCl2 + ? Na3PO4 → ? Fe3(PO4)2 + ? NaCl what is the maximum mass of Fe3(PO4)2 that could be formed from 5.25 g of FeCl2 and 1.62 g of Na3PO4? Answer in units of g
Wednesday, March 13, 2013 at 10:16pm

Chemistry
Indicate the concentration of each ion or molecule present in a mixture of 45.5 mL of 0.274 M NaCl and 65.5 mL of 0.0246 M (NH4)2CO3. Assume that the volumes are additive. [Cl-] [NH4+] [CO32-]
Wednesday, March 13, 2013 at 9:46pm

Chemistry
What mass of silver chloride can be prepared by the reaction of 160.0 mL of 0.25 M silver nitrate with 110.0 mL of 0.20 M calcium chloride? Calculate the concentrations of each ion remaining in solution after precipitation is complete. (Enter a 0 if none of the ion remains.) ...
Wednesday, March 13, 2013 at 9:32pm

Chemistry
Indicate the concentration of each ion present in the solution formed by mixing the following. Assume that the volumes are additive: 3.60 g of KCl in 76.5 mL of 0.274 M CaCl2 solution [K+] = [Cl-] =
Wednesday, March 13, 2013 at 9:30pm

chemistry
the concentrations and pressures at equilibrium were found to be: 1.6 × 10–2 M for A, 8.1 × 103 Pa for B, 13.6 M for C, 13.1 M for D, and 3.9 × 104 Torr for E. Calculate the equilibrium constant, K the right answer is 1x10^12 i tried this problem so many...
Wednesday, March 13, 2013 at 9:04pm

CHEMISTRY
If 7.60 kJ of heat is needed to raise the temperature of a sample of metal from 10.°C to 25°C, how many kilojoules of heat will be required to raise the temperature of the same sample of metal from 35°C to 53°C?
Wednesday, March 13, 2013 at 8:02pm

chemistry
if 150 grams of water is heated from 20 degrees C to 30 degrees C, the number of joules of heat energy aborbed is?
Wednesday, March 13, 2013 at 7:48pm

Chemistry
Calculate the molarity of a solution made by dissolving 16.0 grams of Na2CrO4 in enough water to form exactly 555 mL of solution.
Wednesday, March 13, 2013 at 7:47pm

Chemistry
If 7.60 kJ of heat is needed to raise the temperature of a sample of metal from 10.°C to 25°C, how many kilojoules of heat will be required to raise the temperature of the same sample of metal from 35°C to 53°C?
Wednesday, March 13, 2013 at 7:10pm

Chemistry
N2 + 3H2 --> 2NH3 how many grams of ammonia is produced in the reaction?
Wednesday, March 13, 2013 at 7:04pm

Chemistry
2AgNO3 + BaCl2 --> 2AgCl + Ba(NO3)2 How many grams of sliver chloride are produced from 5.0g of sliver nitrate reacting with an excess of barium chloride?
Wednesday, March 13, 2013 at 7:03pm

Chemistry
If 7.60 kJ of heat is needed to raise the temperature of a sample of metal from 10.°C to 25°C, how many kilojoules of heat will be required to raise the temperature of the same sample of metal from 35°C to 53°C?
Wednesday, March 13, 2013 at 6:28pm

Chemistry
ou are given the following data. S(s) + 3/2 O2(g) → SO3(g) ΔH = -395.2 kJ 2 SO2(g) + O2(g) → 2 SO3(g) ΔH = -198.2 kJ Calculate ΔH for the reaction below. S(s) + O2(g) → SO2(g)
Wednesday, March 13, 2013 at 5:52pm

College Chemistry
Calculate activities of Ca2+ and F- and the solubility of fluorite (CaF2) in pure water at 25C without regard to possible hydrolysis. Assume that all activity coefficients are equal to one. Express the solubility of fluorite in terms of mol/L and g/L.
Wednesday, March 13, 2013 at 3:44pm

chemistry
lewis structure of HOCH2S-
Wednesday, March 13, 2013 at 9:15am

chemistry
Container A holds 767 mL of ideal gas at 2.50 atm. Container B holds 144 mL of ideal gas at 4.70 atm. If the gases are allowed to mix together, what is the resulting pressure?
Wednesday, March 13, 2013 at 8:15am

Chemistry
Consider the titration of 100.0 mL of 0.260 M propanoic acid (Ka = 1.310−5) with 0.130 M KOH. Calculate the pH of the resulting solution after each of the following volumes of KOH has been added. (Assume that all solutions are at 25°C.) (a) 0.0 mL (b) 50.0 mL (c) 100...
Wednesday, March 13, 2013 at 2:56am

Chemistry
Consider the titration of 41.5 mL of 0.213 M HCl with 0.123 M KOH. Calculate the pH of the resulting solution after the following volumes of KOH have been added. (Assume that all solutions are at 25°C.) (a) 0.0 mL (b) 10.0 mL (c) 40.0 mL (d) 80.0 mL (e) 100.0 mL
Wednesday, March 13, 2013 at 2:55am

Chemistry
Calculate the pH of a solution formed by mixing 124.8 mL of 0.481 M KF and 130.7 mL of 0.084 M HClO3.
Wednesday, March 13, 2013 at 2:55am

Chemistry
What volumes of 0.47 M HF and 0.47 M NaF must be mixed to prepare 1.00 L of a solution buffered at pH = 3.50? HF NaF
Wednesday, March 13, 2013 at 2:54am

Chemistry
Calculate the pH after 0.013 mole of gaseous HCl is added to 272.0 mL of each of the following buffered solutions. (Assume that all solutions are at 25°C.) (a) 0.080 M C5H5N and 0.19 M C5H5NHCl (b) 0.72 M C5H5N and 1.52 M C5H5NHCl
Wednesday, March 13, 2013 at 2:54am

Chemistry
You make 1.00 L of a buffered solution (pH = 5.10) by mixing propanoic acid and potassium propanoate. You have 1.00 M solutions of each component of the buffered solution. What volume of each solution do you mix to make such a buffered solution? propanoic acid potassium ...
Wednesday, March 13, 2013 at 2:53am

Chemistry
How many moles of NaOH must be added to 1.0 L of 2.2 M HF to produce a solution buffered at each pH? (a) pH = pKa (b) pH = 4.24 (c) pH = 4.60
Wednesday, March 13, 2013 at 2:48am

Chemistry
Consider a solution that contains both C6H5NH2 and C6H5NH3+. Calculate the ratio [C6H5NH2]/[C6H5NH3+] if the solution has the following pH values. (Assume that the solution is at 25°C.) (a) pH = 4.70 (b) pH = 5.26 (c) pH = 5.42 (d) pH = 4.96
Wednesday, March 13, 2013 at 2:47am

Chemistry
A buffered solution is made by adding 48.6 g C2H5NH3Cl to 1.00 L of a 0.77 M solution of C2H5NH2. Calculate the pH of the final solution. (Assume no volume change. Assume that all solutions are at 25°C.)
Wednesday, March 13, 2013 at 2:47am

Chemistry
Calculate the pH after 0.016 mole of NaOH is added to 1.05 L of a solution consisting of 0.138 M HONH2 and 0.127 M HONH3Cl, and calculate the pH after 0.016 mole of HCl is added to 1.05 L of the same solution of HONH2 and HONH3Cl. (Assume that all solutions are at 25°C.) 0...
Wednesday, March 13, 2013 at 2:46am

Chemistry
Calculate the pH after 0.14 mole of NaOH is added to 1.07 L of a solution that is 0.54 M HF and 1.15 M NaF, and calculate the pH after 0.28 mole of HCl is added to 1.07 L of the same solution of HF and NaF. 0.14 mole of NaOH 0.28 mole of HCl
Wednesday, March 13, 2013 at 2:46am

Chemistry
Calculate the pH of a solution that is 0.124 M C2H5NH2 and 0.124 M C2H5NH3Cl. (Assume that the solution is at 25°C.)
Wednesday, March 13, 2013 at 2:45am

Chemistry Lab
A student who is performing this experiment pours an 8.50mL sample of saturated borax solution into a 10mL graduated cylinder after the borax has cooled to a certain temperature, T. The student rinses the sample into a small beaker using distilled water, and then titrates the ...
Wednesday, March 13, 2013 at 2:34am

Chemistry
50 grams of water at 85ºC were passed through one side of a two-compartment heat exchanger. Sixty-five grams of 30ºC were passed through the other side. Both streams of water came out at 50ºC Calculate the amount of heat given up by the hot water and the amount ...
Wednesday, March 13, 2013 at 1:13am

Chemistry
An insulated container has 54 grams of 90 ªC water. How much ice is required to lower the temperature of 50ºC? No ice remains.
Wednesday, March 13, 2013 at 1:12am

Chemistry
How much energy is required to melt and heat 25 grams of ice at 0ºC to 25ºC?
Wednesday, March 13, 2013 at 1:10am

Chemistry
Which of the following combinations of atomic orbitals can combine to form sigma bonds? s-s s-p p-p hybrid orbital - hybrid orbital hybrid orbital - s hybrid orbital - p
Wednesday, March 13, 2013 at 1:00am

Chemistry
H3BO3 -> H+ + H2BO3- Why doesn't H3BO3 break down to something with H3O+ because it is a weak acid? I know many weak acids break down to something with H3O+ like HCN, C6H5COOH, HNO2, and HF.
Tuesday, March 12, 2013 at 11:26pm

Chemistry
Use activity coefficients to find the concentration of hydrogen ions in a solution of 65.0 mM butanoic acid and 0.01 M NaCl. The ionization constant of butanoic acid is Ka = 1.52 × 10-5. Take the size of C3H7COO– to be 500 pm. Find [H+], pH, and alpha.
Tuesday, March 12, 2013 at 10:49pm

College Chemistry
2NO(g)+O2(g)<->2NO2(g) has KP = 2.77 × 1011 at 25 °C. Suppose a mixture of the reactants is prepared at 25 °C by transferring 0.943 g of NO and 589 mL of O2 measured at 30.7 °C and 829 torr into a 1 L vessel. When the mixture comes to equilibrium, what ...
Tuesday, March 12, 2013 at 9:55pm

Chemistry
What is the change in enthalpy when 17.0 g of liquid mercury is heated by 31°C?
Tuesday, March 12, 2013 at 9:44pm

organic chemistry
what do we need to consider when choosing a solvent to heat under reflux? Would one be the boiling point of the solvent?
Tuesday, March 12, 2013 at 9:13pm

Chemistry
2H2O --> 2H2 + O2 if 30 mL of hydrogen in the above reaction, how many milliliters of oxygen are produced?
Tuesday, March 12, 2013 at 9:12pm

Chemistry
A sample of nitrogen containing 1.5x10^23 molecules has the same number of molecules as a sample containing A. 1.0 mole of H2 B. 2.0 moles of He C. 0.25 mole of O2 D. 0.50 mole of Ne
Tuesday, March 12, 2013 at 8:48pm

Chemistry
A sample of nitrogen containing 1.5x10^23 molecules has the same number of molecules as a sample containing A. 1.0 mole of H2 B. 2.0 moles of He C. 0.25 mole of O2 D. 0.50 mole of Ne
Tuesday, March 12, 2013 at 8:47pm

Chemistry
2H2O --> 2H2 + O2 if 30 mL of hydrogen in the above reaction, how many milliliters of oxygen are produced?
Tuesday, March 12, 2013 at 8:41pm

chemistry
I need 1L of a pH 4 buffer with a total molarity of 1. Propose a buffer system and a recipe to achieve this goal. (acetic acid/acetate would probably be a good choice.) help please!
Tuesday, March 12, 2013 at 8:28pm

chemistry
I need 1L of a pH 4 buffer with a total molarity of 1. Propose a buffer system and a recipe to achieve this goal. (acetic acid/acetate would probably be a good choice.) help please!
Tuesday, March 12, 2013 at 8:25pm

Chemistry
If you add enough water to 175.0 mL of a .15 M NaCl solution until the final volume is 350.0 mL, what will the molarity of the diluted solution be?
Tuesday, March 12, 2013 at 7:25pm

Chemistry
2H2O --> 2H2 + O2 if 30 mL of hydrogen in the above reaction, how many milliliters of oxygen are produced?
Tuesday, March 12, 2013 at 6:38pm

chemistry
1L of a buffer composed of acetic acid and sodium acetate has a pH of 4.3 (total molarity=0.0774) what is the capacity of 200mL of the buffer to survive an addition of HCl without changing by more than 0.4 pH units? i am so lost please help! i know you use the henderson ...
Tuesday, March 12, 2013 at 6:25pm

university chemistry
many cola soft drinks contain caffeine and benzoic acid (pKa 4.2), explain how you would isolate separately pure caffeine and benzoic acid from an aqueous solution containing both compounds
Tuesday, March 12, 2013 at 6:24pm

chemistry
Which of the following combinations of atomic orbitals can combine to form sigma bonds? s-ss-pp-phybrid orbital - hybrid orbitalhybrid orbital - shybrid orbital - p What is the bond angle (in degrees) resulting from sp hybridization? What is the bond angle (in degrees) ...
Tuesday, March 12, 2013 at 6:22pm

chemistry
What is the dominant form of secondary bonding for CH3Cl? Dipole-dipole interactions London dispersion forces Covalent bonding Ionic bonding
Tuesday, March 12, 2013 at 6:20pm

chemistry
Carbon reacts with chlorine and hydrogen to form the compound CH3Cl. (a) Construct the structure of CH3Cl.
Tuesday, March 12, 2013 at 6:11pm

Chemistry
How many moles of gas are in a 30 liter scuba canister if the tempature of the canister is 300 k and pressure is 200 atmospheres?
Tuesday, March 12, 2013 at 5:51pm

chemistry
If you start with 40.30 grams of silver nitrate and excess HCl, how much silver chloride could I make?
Tuesday, March 12, 2013 at 5:48pm

Chemistry
A salicyclic acid (MW= 138.123 g/mol) solution has a pH of 2.43. When 100 ml of this solution was evaporated 0.22g of dry salicylic acid was recovered. What is the Ka of salicylic acid?
Tuesday, March 12, 2013 at 5:38pm

Chemistry
For 520ml water calculate initial and final pH after adding 0.02ml HCl
Tuesday, March 12, 2013 at 5:22pm

Chemistry
(1) Use the thermodynamic values to (a) deduce the enthalpy change of each reaction (b)state if the reaction is exothermic,or endothermic,and also how much energy is released or absorbed. For thi reactions; (1) NH4NO3 (s)------>N2 (g) + 2H2O (l) (2) 4Zn (s) + 9HNO3 (aq...
Tuesday, March 12, 2013 at 3:55pm

chemistry
3. You will be using 10.0 mL of silver nitrate solution labeled 170.0 g/L. How many grams of silver nitrate will be in your 10.0 mL sample?
Tuesday, March 12, 2013 at 3:45pm

Chemistry
Do elements with higher masses always have lower average velocity than those elements with a low mass? Thanks
Tuesday, March 12, 2013 at 3:32pm

Chemistry
A salicyclic acid (MW= 138.123 g/mol) solution has a pH of 2.43. When 100 ml of this solution was evaporated 0.22g of dry salicylic acid was recovered. What is the Ka of salicylic acid?
Tuesday, March 12, 2013 at 3:25pm

Chemistry
Starting with solid Tris base (FW 121.1) and 1 M HCl, describe how you would make 2 liters of 200 mM Tris-HCl buffer pH 7.5. pKa of Tris 8.14
Tuesday, March 12, 2013 at 3:24pm

Chemistry 104
A 0.30M solution of a weak monoprotic acid is 0.41% ionized. what is the acid-ionization constant, Ka for this acid? Use. HA + H2O <==> H3O + A to figure out X for H3O and A
Tuesday, March 12, 2013 at 1:15pm

chemistry
calculate the theoretical potential of each of the following cells.is the cell reaction spontaneous as written or spontaneous in the oppsite direction? Bi|BiO+(0.04M),H+(0.2M)||I-(0.1M),AgI(sa​t`d)|Ag help meeeee
Tuesday, March 12, 2013 at 1:08pm

chemistry
I need 1L of a pH 4 buffer with a total molarity of 1. Propose a buffer system and a recipe to achieve this goal. (acetic acid/acetate would probably be a good choice.) help please!
Tuesday, March 12, 2013 at 12:56pm

chemistry
1L of a buffer composed of acetic acid and sodium acetate has a pH of 4.3 (total molarity=0.0774) what is the capacity of 200mL of the buffer to survive an addition of HCl without changing by more than 0.4 pH units? i am so lost please help! i know you use the henderson ...
Tuesday, March 12, 2013 at 12:45pm

chemistry
Construct the correct structure for AsClF42-. You can begin by selecting an option from the menu on the right, then by filling in atoms and electron pairs (ep, if any) into the appropriate locations. Please construct the molecule such that the dipole is oriented vertically up ...
Tuesday, March 12, 2013 at 11:03am

chemistry
Use molecular orbital theory to predict whether the bond order in the superoxide ion, O2-, should be higher or lower than the bond order in neutral O2 molecule. Is the bond order of O2- higer or lower than that of O2?
Tuesday, March 12, 2013 at 11:02am

chemistry
what volume of oxygen at STP is required to affect complete combustion of 200cc of acetylene and what would be the volume of co2 formed?
Tuesday, March 12, 2013 at 10:32am

chemistry
a 23.8 g sample of unknown metal heated at 100 degrees c is placed in 50.0 mL of water at 24 degrees c resulting in 8.5 c temperature increase. What is the specific heat of the metal
Tuesday, March 12, 2013 at 9:50am

university chemistry
this is for a chemistry laboratory experiment called "how much caffeine is there in instant coffee" What should be the pH of the aqueous layer to extract caffeine? There are three aqueous solutions that you may choose from. A. pH >14, using 2.5 M NaOH (aq) B. pH 1...
Tuesday, March 12, 2013 at 9:11am

CHEMISTRY HELP!!
When BaCl2 reacts with Na3PO4, Ba3(PO4)2 and NaCl are formed. Balance the equation and write the coefficients in the blanks.
Tuesday, March 12, 2013 at 6:28am

Physical chemistry 2
50 ml of 0.02M acetic acid is titrated with 0.1M NaOH.Calculate the pH of the solution when 10ml of NaOH is added
Tuesday, March 12, 2013 at 12:41am

Chemistry
How many grams of NH3 can be produced if 105g of NH4OH are completey decomposed?
Tuesday, March 12, 2013 at 12:03am

Chemistry
Compare the g/L solubility of CaCO3 in pure water, a H3O+ (aq) solution with a PH of 3.00 and a H30+(aq) solution with a pH of 1.00. Ksp for CaCO3 is 3.36 x 10^-9 CaCO3 (s) + H3O (aq) = Ca (aq) + HCO3 (aq) + H2O (l) (equilibrium equation) Keq= 71 I knew how to do this for pure...
Monday, March 11, 2013 at 11:05pm

chemistry
Chlorine gas is collected in a gas collecting tube above water. The gas is at 20oC and the total pressure in the tube is 755 mmHg. What is the pressure (in mmHg) of chlorine gas in the tube?
Monday, March 11, 2013 at 10:01pm

Chemistry
Calculate the pH for each of the following points in the titration of 50.0 mL of a 2.7 M H3PO3(aq) with 2.7 M KOH(aq). pKa1 = 1.3 and pKa2 = 6.7 a) before addition of any KOH b) after addition of 25.0 mL of KOH c) after addition of 50.0 mL of KOH d) after addition of 75.0 mL ...
Monday, March 11, 2013 at 9:26pm

Chemistry
Calculate the pH at the equivalence point for the titration of 0.200 M methylamine (CH3NH2) with 0.200 M HCl. The Kb of methylamine is 5.0× 10–4.
Monday, March 11, 2013 at 9:23pm

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