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May 5, 2015

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

chemistry
What is the maximum amount of silver in grams that can be plated out of 3.8L of an AgNO3 solution containing 3.3% Ag by mass? (Assume that the density of the solution is 1.02g/mL .)
Saturday, November 29, 2014 at 9:30pm

Chemistry
What would you do in order to solve this question: "The enthalpy of combustion for benzoic acid is -3223.6kj/mol. Use the values of the standard enthalpies of formation of liquid water and CO2 to calculate standard enthalpy of formation of benzoic acid."
Saturday, November 29, 2014 at 9:27pm

chemistry
I'm working on substitution organic chemistry problems and I just had a question. There's an equation in which a molecule is treated with methanol in an acetone solution. Would the reaction be SN1 or SN2? I thought that it was SN2 because of the aprotic acetone, but ...
Saturday, November 29, 2014 at 8:59pm

Chemistry
During a Breathalyzer Test it was determined that 1.60mg of K2Cr2O7 was consumed by the above reaction. Calculate the number of milligrams of ethanol in the test sample.
Saturday, November 29, 2014 at 8:54pm

chemistry
Determine the pH (to two decimal places) of a solution prepared by adding 395 mL of 0.0360 M benzoic acid (C6H5COOH) to 12.5 g of sodium benzoate (NaC6H5COO).
Saturday, November 29, 2014 at 8:41pm

Chemistry
Let’s assume you have 250 ml of a 1.3M KOH solution and you want to neutralize it with the acid HBr. It takes 350 ml of the HBr solution to do so. What must have been the molarity of the HBr solution? HBr(aq) + KOH(aq) => KBr(aq) + H2O(l) The stoichiometry is already ...
Saturday, November 29, 2014 at 6:59pm

Chemistry
For an H+ concentration, [H+], of 4.3 x 10-4 M, would this be acidic, neutral or basic? Why? I'm assuming that because it is an H+ it would be acidic and H+ means acidic and OH- means base. Is this correct? And is there a better formula for this equation?
Saturday, November 29, 2014 at 6:53pm

Chemistry
What does 0.053 M NaCl mean? How many grams of sodium chloride are needed to make 5.0 liters of this solution?
Saturday, November 29, 2014 at 5:37pm

Chemistry
To make 250 ml of a 5%(w/v) calcium carbonate solution, how many grams of calcium carbonate will I need?
Saturday, November 29, 2014 at 5:35pm

chemistry
nitric acid is composed of HNO3 molecule.A sample of 4.50 g was obtained. calculate the number of oxygen atom in the sample. this is what i do .can u check if i am wrong or miss something answer : mole HNO3 = 4.50g/63 = 0.07 mol mole : no of particle/NA = 0.07x (avogardo ...
Saturday, November 29, 2014 at 5:10pm

chemistry
A balloon filled with 85 g of nitrogen gas that produced a pressure of 3.25 atm at 58C. What is the volume of the balloon/
Saturday, November 29, 2014 at 5:00pm

Chemistry
hydrogen gas is collected over water at a total pressure of 744 mm Hg at 20.0 C. If the volume of the wet hydrogen is 495 mL, what will the dry volume be at standard conditions? I know that you need to subtract the water vapor pressure from the total and I got 726.45 mmHg. (...
Saturday, November 29, 2014 at 4:35pm

chemistry
To make a phosphorus fertilizer, agricultural companies use the following reaction: Ca3P2O8 + 2H2SO4 --> CaH4P2O8 + 2CaH4SO6 (fertilizer) If 1.50 * 10^4 grams of H2SO4 are reacted with excess Ca3P2O8 and H2O, how many grams of fertilizer can be made? Hi, I pretty much get ...
Saturday, November 29, 2014 at 3:20pm

chemistry
What volume of a 0.550 M solution of potassium hydroxide can be made with 14.3 g of potassium hydroxide? (Ignore significant figures for this problem.)
Saturday, November 29, 2014 at 3:16pm

chemistry
cal culate the ph of a mixture of 100 ml distilled water and 2 ml of 2M of NaOH
Saturday, November 29, 2014 at 1:08pm

chemistry
titration of 50ml of 0.25ammonia with 0.5M HCL . a) find the initial PH value b) volume of HCL is required to reach the equivalent poinnt c)the ph at the equivalence point
Saturday, November 29, 2014 at 12:59pm

Chemistry
What are the steps to solve this problem? "The enthalpies of combustion of glucose and ethanol are -2813kj/mol and -1369kj/mol, use Hess's law to calculate the enthalpy change when 0.500 kg of glucose is allowed to ferment." Please help.
Friday, November 28, 2014 at 11:18pm

Chemistry
I'm not sure how to calculate the ΔH°rxn for 3 Al + 3 NH4ClO4 -> Al2O3 + AlCl3 + 3 NO + 6 H2O. I'm honestly not sure where to start with this problem.
Friday, November 28, 2014 at 9:09pm

Chemistry
Given that many laboratory gases are sold in steel cylinders with a volume of 43.8 L, What mass (in grams) of argon is inside a cylinder whose pressure is 17810kPa at 24∘C? I've attempted this problem but I'm not getting the correct answer. Please explain if you ...
Friday, November 28, 2014 at 8:09pm

Chemistry
If 14.5g of CO2 gas has a volume of 0.13L at 305K , what is its pressure in millimeters of mercury? I've plugged these values into the equation P=nRT/V but I am having troubles with canceling labels and getting the correct answer. Please explain as much as possible to me!
Friday, November 28, 2014 at 8:08pm

Chemistry
At 2000°C the equilibrium constant for the reaction is Kc = 2.4 ✕ 103. 2 NO(g) equilibrium reaction arrow N2(g) + O2(g) If the initial concentration of NO is 0.160 M, what are the equilibrium concentrations of NO, N2, and O2? I do not even know how to ...
Friday, November 28, 2014 at 5:19pm

Chemistry
Calculate Delta H for the following equation: Zn(s) + 2H+(aq) = Zn2+(aq) + H2(g)
Friday, November 28, 2014 at 1:16pm

chemistry
the volume of a certain bacterial cell is 1.44 μm3. what is the volume of 1 x 10 ^5 cells in liters
Friday, November 28, 2014 at 12:44pm

chemistry
At temperatures above 0°C, what is the sign of the change in free energy for the conversion of liquid water to ice? A. Positive B. Zero C. Negative D. Not known
Thursday, November 27, 2014 at 11:18pm

chemistry
3CuCl2 *2H2O + 2Al = 3Cu + 2AlCl3 + 6H2O Determine the number of grams that should have been produced when 1.25g of copper (2) chloride dehydrate reacts with excess aluminum so i'm not really sure how you're supposed to calculate the number of grams with hydrates?? ...
Thursday, November 27, 2014 at 9:45pm

Chemistry
I don't know how to do this question, or even start it. Please Help. 2 kg copper kettle (specific heat capacity 0.385j/gC) has .0500 kg of water at 20C. How much heat is needed to raise the temperature of the kettle and content to 80C?
Thursday, November 27, 2014 at 9:17pm

Chemistry
compose the micelle 2 agno3 + bacl2 - 2Agcl + ba (no3) 2
Thursday, November 27, 2014 at 8:00am

chemistry
can you please give me one practical application of analytical chemistry in being a medical technologist? i know it will determine the separation event happening on the lab test... but is that already a practical application? or i have to cite a deeper example? please give me ...
Thursday, November 27, 2014 at 6:20am

chemistry
A sample of gas in a balloon has an initial temperature of 9.0∘C and a volume of 1.75×103L . If the temperature changes to 80.∘C , and there is no change of pressure or amount of gas, what is the new volume, V2, of the gas?
Thursday, November 27, 2014 at 2:36am

chemistry
If the ΔH for H2O(l) → H2O(s) is -6.01 kJ, then what is the ΔH for 2H2O(s) → 2H2O(l)? A. -12.02 kJ B. 6.01 kJ C. -6.01 kJ D. 12.02 kJ I think d is the answer
Thursday, November 27, 2014 at 12:25am

Chemistry
At temperatures above 0°C, what is the sign of the change in free energy for the conversion of liquid water to ice? A. Positive B. Zero C. Negative D. Not known
Thursday, November 27, 2014 at 12:24am

chemistry
For which of the reactions listed below will Gibbs free energy always be negative? A. An exothermic reaction that increases in entropy B. An endothermic reaction that decreases in entropy C. An endothermic reaction that increases in entropy D. An exothermic reaction that ...
Thursday, November 27, 2014 at 12:23am

Chemistry
The reaction: H2C2O4 + CuO + Heat = ? This reaction was produced in organic elemental analysis to identify C and H. So I think CO2 is formed to react with Ca(OH)2 to giving CaCO3. Additionally was formed H2O, so I though H2 or H2O was produced. Is correct : = C2CuO4 + CO2 + H2 ?
Wednesday, November 26, 2014 at 9:19pm

Chemistry
copper is a product of the reaction that occurs when dry ammonia is passed over a sample f heated copper(2) oxide.The equation for the reaction is given: 2NH3+3CuO=3Cu+3H2O+N2 Calculate the mass of copper produced if 0.12dm^3 of nitrogen is produced at room temperature and ...
Wednesday, November 26, 2014 at 9:13pm

Chemistry
What is Gibbs free energy? A. The energy lost as heat to the surrounding molecules B. The usable energy released or absorbed by a reaction C. The energy in the form of kinetic energy in a system D. The energy contained within the bonds of molecules
Wednesday, November 26, 2014 at 6:32pm

chemistry
What is the balanced chemical equation of Shampoo? And what is the chemical reaction of it? Please i need a help ASAP! Thank you!
Wednesday, November 26, 2014 at 6:16pm

chemistry
What is the balanced chemical equation Shampoo? please i need a help ASAP!
Wednesday, November 26, 2014 at 6:03pm

chemistry
State the number of valence electrons for an iron(II) ion in an ionic bond.
Wednesday, November 26, 2014 at 5:07pm

Chemistry
please help! I don't understand any of this. Using the Solubility Rules, write the balanced molecular, total ionic, and net ionic equations (including physical states) for the following: Hints: There is no such thing as an Na3+. Na is in group 1A, so you know it can only ...
Wednesday, November 26, 2014 at 3:19pm

Chemistry
1. Write a balanced molecular equation for the reaction of solid AgNO3 with aqueous NaCl. Be sure to include the correct number of coefficients and the state of the species (aq, s, l or g). 2. Write the total ionic equation for this reaction, including all physical states. 3. ...
Wednesday, November 26, 2014 at 3:17pm

CHEMISTRY
write oxidation and reduction halfreaction of 3CuO+2NH3>3Cu+N2+3H2O
Wednesday, November 26, 2014 at 10:05am

CHEMISTRY
how can different steps in the analytical process help in solving probs in Analytical Chemistry
Wednesday, November 26, 2014 at 7:59am

chemistry
can you please give me some practical applications of qualitative chem and quantitative chem...
Wednesday, November 26, 2014 at 7:58am

CHEMISTRY HELP
how can analytical chemistry help on different fields of sciences and technology?
Wednesday, November 26, 2014 at 7:57am

Chemistry
What is the formula for copper chloride dihydrate ? And can 1 get more info on it plz (like an overall overview) ? Tnx
Wednesday, November 26, 2014 at 4:42am

chemistry
The G value for formation of gaseous water at 298 K and 1 atm is -278 kJ/mol. What is the nature of the spontaneity of formation of gaseous water at these conditions? A. The reaction is never spontaneous. B. The reaction is sometimes spontaneous. C. The reaction is spontaneous...
Tuesday, November 25, 2014 at 11:48pm

chemistry
Calculate the pressure exerted by 1.2 mol\rm mol of gas in a volume of 28.2 L\rm L and at a temperature of 334 K\rm K.
Tuesday, November 25, 2014 at 11:08pm

chemistry----please help
calculate the molar hydroxide ion concentration of each of the following solutions given the pH 4.53. Answer should be for OH-. Please show me how to do this in step by step I tried putting in 10 xy-4.53= 0.000029512 which is 3.0 * 10^-5 It says that the answer is wrong.
Tuesday, November 25, 2014 at 10:33pm

Chemistry
100 mL of LiNO3, 0.241 M is mixed with 240 mL of 0.618 M Ca(NO3)2. What is the final concentration of NO3- in the solution?
Tuesday, November 25, 2014 at 9:25pm

Chemistry
4P + 50_2 ---> 2P205 25.4g of P are used with excess 02 how many grams of p205 should theoretically form I have no idea where to start im lost
Tuesday, November 25, 2014 at 9:20pm

Chemistry
calculate the molar hydroxide ion concentration of each of the following solutions given the pH 4.53. Answer should be for OH-. Please show me how to do this in step by step
Tuesday, November 25, 2014 at 8:49pm

chemistry
State the number of valence electrons for a chloride ion in an ionic bond.
Tuesday, November 25, 2014 at 8:39pm

chemistry
State the number of valence electrons for an iron(II) ion in an ionic bond.
Tuesday, November 25, 2014 at 8:38pm

chemistry
Assuming all gases are at the same temperature and pressure, how many milliliters of hydrogen gas must react to give 49.0mL of NH3? 3H2(g)+N2(g)→2NH3(g)
Tuesday, November 25, 2014 at 8:14pm

Chemistry
Assuming all gases are at the same temperature and pressure, how many milliliters of hydrogen iodide are produced from 160mL of H2? H2(g)+I2(g)→2HI(g)
Tuesday, November 25, 2014 at 8:14pm

chemistry
How many milliliters of oxygen gas at STP are released from heating 5.15g of calcium chlorate? Ca(ClO3)2(s)→CaCl2(s)+3O2(g)
Tuesday, November 25, 2014 at 8:14pm

Chemistry
A substance has the following properties: Heat capacities: 1.34 J/g oC (solid) 3.02 J/g oC (liquid) 2.55 J/g oC (gas) Heat of Fusion = 4.23 kJ/mole Heat of Vaporization = 23.5 kJ/mole Boiling Point = 88.5 oC Melting Point = -30.0 oC Molar Mass = 96.3 g/mole How much energy (in...
Tuesday, November 25, 2014 at 7:55pm

Chemistry
0.15 grams of benzene (C6H6) is dissolved into 4.7 grams of melted biphenyl. The freezing point of the mixture was determined to be 4.7 degrees below the freezing point of pure biphenyl. Based on these results, what is the Kf of biphenyl? (Use the standard units in your ...
Tuesday, November 25, 2014 at 6:14pm

Chemistry
What is Gibbs free energy? A. The energy lost as heat to the surrounding molecules B. The usable energy released or absorbed by a reaction C. The energy in the form of kinetic energy in a system D. The energy contained within the bonds of molecules
Tuesday, November 25, 2014 at 5:59pm

chemistry
What is ΔH in the equation ΔG = ΔH - TΔS? A. The change in specific heat between the products and the reactants B. The change in enthalpy between products and reactants in a reaction C. The change in entropy between products and reactants in a reaction D. ...
Tuesday, November 25, 2014 at 5:34pm

chemistry
What would cause entropy to increase in a reaction? A. The products forming a more rigid structure B. The products forming an ordered pattern C. The products becoming more spread out D. The products forming fewer molecules I think the answer is c or d
Tuesday, November 25, 2014 at 5:13pm

Chemistry help drbob222
Which of the following processes would result in a negative entropy change? A. Leaves falling off a tree B. A deck of cards falling on the floor C. A piece of cake crumbling as it is cut D. A student filing papers I think d
Tuesday, November 25, 2014 at 4:17pm

Chemistry
If the student collected 3.46g of acetone and the theoretical yield is 3.67 g, what is the percent yield?
Tuesday, November 25, 2014 at 3:49pm

Chemistry
How many grams of oxygen gas must react to give 2.80g of ZnO? 2Zn(s)+O2(g)→2ZnO(s)
Tuesday, November 25, 2014 at 3:47pm

Chemistry
How many grams of oxygen gas must react to give 2.80g of ZnO?
Tuesday, November 25, 2014 at 3:43pm

Chemistry
Given the molar concentration of hydroxide ion, calculate the concentration of hydrogen ion. [OH-]=0.0010 Can someone please help me with this process. Thanks
Tuesday, November 25, 2014 at 3:23pm

Chemistry
Determine the acid and base that were neutralized to produce each of the following salts. Li2CO3 (aq). I don't understand how to solve this.
Tuesday, November 25, 2014 at 2:41pm

Chemistry
If 45.5 g of calcium carbonate is reacted with phosphoric acid, how many grams of carbon dioxide will be produced if the reaction yield is 85.0 %?
Tuesday, November 25, 2014 at 2:40pm

Chemistry
Given the molar concentration of hydrogen ion, calculate the concentration of hydroxide ion [H+]=7.9*10-7
Tuesday, November 25, 2014 at 2:39pm

Please Help Me With This Chemistry HW Question!
Should 25 ml of 0.15 M HCL solution be added to 250 mL of buffer solution containing 0.25M HF Ka-7.1 x 10, and 0.40 M NaF at a pH of 3.15 what is the new pH?
Tuesday, November 25, 2014 at 2:27pm

Chemistry
How many grams of CO2 could be produced from the combustion of 0.0713 mol. of C2H4 in the presence of 0.156 mol. of O2?
Tuesday, November 25, 2014 at 2:19pm

Chemistry
Calculate how much acetylene (C2H2) can be produced from 358 g of H2O and an excess of CaC2 if the percent yield for this reaction is 94.5%. CaC2 + 2H2O -> C2H2 + Ca(OH)2
Tuesday, November 25, 2014 at 12:29pm

Chemistry
3NO2 + H2O -> 2HNO3 + NO Calculate the percent yield for the following reaction if 76.8 g of H2O reacted and 125 g of NO were produced.
Tuesday, November 25, 2014 at 12:25pm

Chemistry
68.0g of solute were dissolved in 393 mL of benzene. The solution froze at -0.50°C. The normal freezing point of benzene is 5.5°C and the molar freezing point constant is 5.12°C kg/mol. The density of benzene is .879 g/mol. Calculate the molar mass of the solute.
Tuesday, November 25, 2014 at 11:03am

Chemistry
In a routine laboratory analysis, a solution of sodium chromate with a chromium concentration of 175.0 ppm is required. Calculate the molarity of this solution.
Tuesday, November 25, 2014 at 10:59am

chemistry
how many grams of BaCl2 are present in 150 g of H20 if the concentration is 0.3 m?
Tuesday, November 25, 2014 at 10:38am

chemistry
how many moles of BaCl2 are in 300 g of H2O if the molality is 0.2 m?
Tuesday, November 25, 2014 at 10:37am

chemistry
what is the molality of 18 g NaCl in 200 g of H2O?
Tuesday, November 25, 2014 at 10:36am

chemistry
3moles KI in 500 g of H2O equals what molality?
Tuesday, November 25, 2014 at 10:35am

chemistry
how many ml of 0.5 M BaCl2 are needed to have 75 g of BaCl2?
Tuesday, November 25, 2014 at 10:34am

chemistry
what volume of 0.5 BaCl2 is needed to have 0.1 moles of BaCl2?
Tuesday, November 25, 2014 at 10:33am

chemistry
how many moles of Kl are present in 500 ml of a 0.2 M solution?
Tuesday, November 25, 2014 at 10:32am

chemistry
calculate the molarity of a g NaCl in 250 ml solution.
Tuesday, November 25, 2014 at 10:32am

chemistry
3 moles C6H12O6 in 100 ml equals what molarity?
Tuesday, November 25, 2014 at 10:31am

Chemistry
How do I balance CuSO4 + NH3 + H2O = (NH4)2SO4 + Cu(NH3)4(OH)2 Thank you!!!
Monday, November 24, 2014 at 11:32pm

chemistry 2
A certain laser uses a gas mixture consisting of 9.0 grams of Hydrogen chloride, 2.0 grams Hydrogen gas, and 165.0 grams of Neon. What pressure is exerted by the mixture in a 75.0 liter tank at 22 degree Celsius? Which gas has the smallest partial pressure?
Monday, November 24, 2014 at 10:45pm

Chemistry
In 250 mL of a 0.35 M solution of NaOH, there are how many grams of NaOH?
Monday, November 24, 2014 at 10:41pm

Chemistry
how many Kj of heat are evolved when 6g of pure carbon is completely burned? how many grams of carbon must be burned to furnish 39.3 kJ of heat. enthalpy of combustion of carbon is -393.5
Monday, November 24, 2014 at 10:40pm

Chemistry
The equilibrium constant for the reaction H2 + I2 --> 2HI, is 54 at 425 degrees C. If the equilibrium mixture contains 0.030 M HI and 0.015 M I2, calculate the equilibrium concentration of H2.
Monday, November 24, 2014 at 10:40pm

chemistry-naming
How do I name the following- C3H8? (the numbers are supposed to be subscripts) KCl?
Monday, November 24, 2014 at 9:58pm

Chemistry
What is the concentration of sodium phosphate contains 0.60 M Na+? I'm not sure what to do and how to figure how to do this question.
Monday, November 24, 2014 at 9:57pm

Chemistry
2 ml of stock antibiotic (64 mg/ml) was diluted into a test tube containing 2 ml of broth (final volume is 4). A series of 2-fold SERIAL DILUTIONS were performed by transferring 2 ml to three other tubes, consecutively (final volumes now 2 ml in each tube). The final ...
Monday, November 24, 2014 at 9:26pm

Chemistry
A sample of lithium sulfate, Li2SO4, contains 6.78 x 10^23 formula units. a) How many moles of Li+ ions are there in the sample? b) How many moles of ions are there in the sample? My work. I think a) is 2.26 is that correct?
Monday, November 24, 2014 at 7:25pm

Chemistry
Provide the name(s) for the branched constitutional isomer(s) with the molecular formula C7H16 that have three methyl groups.
Monday, November 24, 2014 at 7:00pm

Chemistry
A sample of toluene, C7H8 has a mass of 74.5 g. How many carbon atoms does it contain? How many hydrogen atoms does it contain? My work: I get 3.41 x 10^24 for carbon atoms And 3.90 x 10^24 for hydrogen atoms. Is this correct?
Monday, November 24, 2014 at 6:44pm

chemistry
What mass of AuCl3 contains 160.9 g of gold? My work i got 104.6 g is that correct
Monday, November 24, 2014 at 6:21pm

Chemistry
A sample of toluene, C7H8 has a mass of 74.5 g. a) how many molecules does the sample contain? b) How many carbon atoms does it contain? How many hydrogen atoms does it contain? My work For b would it be 7 carbon atoms and 8 hydrogen atoms
Monday, November 24, 2014 at 6:00pm

PLEASE HELP CHEMISTRY
What mass of pure silver would you obtain from 85.0 g of AgNO3? I got 53.55 g is that correct?
Monday, November 24, 2014 at 5:47pm

chemistry
I just need a definitive answer because I've searched everywhere and it's made me second guess my original answer. How many valence electrons does copper have? I thought it was one but now I'm unsure. I know it's electron configuration is [Ar]4s1 3d10, so that...
Monday, November 24, 2014 at 5:46pm

Chemistry
A sample of lithium sulfate, LiSO4, contains 6.78 x 10^23 formula units. a) How many moles of Li+ ions are there in the sample? b) How many moles of ions are there in the sample? My work: I think a) is 2.26 moles And b i am not sure
Monday, November 24, 2014 at 5:36pm

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