Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
Lead can be extracted from lead(II) sulfide, PbS, in two stages. Stage 1: Lead(II) sulfide is heated in air. It reacts with oxygen to produce lead(II) oxide and sulfur dioxide. Stage 2: The Lead(II) oxide is then heated in a blast furnace with coke. (a) Write a chemical ...
Monday, April 22, 2013 at 2:37pm

Chemistry 110, college
A solution is prepared by dissolving 56.5g of ethylene glycol in 874 g of water. Calculate the change in the boiling point and the freezing point.
Monday, April 22, 2013 at 2:05pm

chemistry
What is the osmotic pressure in torr of a 0.0155 M glucose solution at body temperature ( 35.7 °C)? What are the boiling and freezing points for the same solution?
Monday, April 22, 2013 at 1:01pm

chemistry
how many milliliter of .750M sulfuric acid are needed to neutralize completely 20 g of NaOH?
Monday, April 22, 2013 at 12:04pm

chemistry
if burning one mole releases 1310.0 kj, then how many moles will release 227.30?
Monday, April 22, 2013 at 11:44am

Chemistry
Suppose you wanted to find out how many milliliters of 1.0 M AgNO3 are needed to provide 169.88 g of pure AgNO3. a. What is step 1 in solving the problem? b. What is the molar mass of AgNO3? c. How many milliliters of solution are needed?
Monday, April 22, 2013 at 11:26am

Chemistry
How much energy, in kj, is absorbed by 23.8g of acetone when it evaporates if its molar heat of vaporization is 32.0 kj/mol?
Monday, April 22, 2013 at 9:33am

chemistry
is there a chemical equation for gadolinium medium contrast?
Monday, April 22, 2013 at 9:11am

chemistry
For each of the following primary standard acids, write the titration equation and calculate the volume of 0.100 M NaOH required for the titration: (i) 300 mg benzoic acid (C6H5COOH) (ii) 200 mg oxalic acid dihydrate (C2O4H2.2H2O) Equations: (i): C6H5COOH +NaOH->NaC6H5COO +...
Monday, April 22, 2013 at 6:45am

chemistry
Calculate the weight (in mg) of borax Na2B4O7.10H20 required to react with 25.0 mL if 0.100 M HCI No. moles HCl consumed = __________ moles No. moles borax required = __________ moles Molar mass of borax = __________ g mol-1 (Na2B4O7.10H2O) Weight borax required = __________ g...
Monday, April 22, 2013 at 6:04am

chemistry
15.0 mL of 8.00 M NaOH was diluted with water to 500 mL. Calculate the molarity of the diluted NaOH solution. My calculations: 0.015L x 8.00moles/1L x 39.997/1mole = 4.8g M= (4.8g x 1mole/39.997) / 0.500L = 0.24M is my workings correct? Is there another way to get to this?
Monday, April 22, 2013 at 5:55am

chemistry
STANDARDISATION OF 0.1 M HCl Borax dissolves slowly in water at room temperature. Why do we not use a stirring rod to mix the solution and speed up this stage of the experiment?
Monday, April 22, 2013 at 5:01am

Chemistry
25 mL 0.1 M acetic acid is titrated with 0.1 M NaOH. Calculate the pH after the addition of 0.0 mL, 1.0 ml, 2.5 mL, 4.0 mL, 7.0 mL, 10.5 mL, 15.0 mL, 17.0 mL, 20.0 mL, 22.0 mL, 23.0 mL, 23.5 mL, 24.0 mL, 24.25 mL, 24.5 mL, 24.75 mL, 25.0 mL, 25.25 mL, 25.5 mL, 25.75 mL, 26.0 ...
Monday, April 22, 2013 at 4:34am

Chemistry
Need type of reaction and balance of (NH4)2S+CuSO4=
Monday, April 22, 2013 at 3:07am

Chemistry
(NH4)2S+CuSO4=
Monday, April 22, 2013 at 3:06am

chemistry
Using the PM3 semiempirical method in HyperChem, treat planar napthalene. First build the molecule, choose SemiEmpirical methods and PM3, and perform a Geometry Optimization. Look in the "Compute>Orbitals" menu to determine the energies of the HOMO and LUMO. What ...
Monday, April 22, 2013 at 2:55am

Organic Chemistry
A student dehydrated 12 grams of 2-methylcyclohexene with 85% H3PO4, and acquired 6.50 grams of alkene. What are the theoretical and percent yields?
Monday, April 22, 2013 at 2:32am

Organic Chemistry
A student dehydrated 12 grams of 2-methylcyclohexene with 85% H3PO4. What are the theoretical and percent yields?
Monday, April 22, 2013 at 2:28am

Organic Chemistry
A student dehydrated 12 grams of 2-methylcyclohexene with 85% H3PO4. What are the theoretical and percent yields?
Monday, April 22, 2013 at 2:27am

chemistry
predict which three of the following five aqueous solutions should react with solid aluminum metal (the elemental form of aluminum): AgNO3, Na2CO3, CuSO4, CaCl2, Pb(NO3)2
Monday, April 22, 2013 at 1:25am

Chemistry
I had to share a diagnostic procedure that I had done. I shared a breast MRI, in which I had contrast. Now I need to share on balanced chemcial equation related to this, and be sure to be specific. Can someone please help me??
Monday, April 22, 2013 at 12:47am

chemistry
Determine how much of each product (in g or L) is formed. 2.50g of aluminum metal is placed in a large container of concentrated copper (ll) suflate to produce copper metal.
Sunday, April 21, 2013 at 11:50pm

chemistry
A 32.0-g sample of water at 290. K is mixed with 51.0 g water at 310. K. Calculate the final temperature of the mixture assuming no heat loss to the surroundings.
Sunday, April 21, 2013 at 10:55pm

chemistry
Identify the limiting reagent. 2.43g of magnesium is added to a solution containing 0.100 mol hydrochloric acid t ok produce hydrogen gas.
Sunday, April 21, 2013 at 10:14pm

Chemistry
calculate the ph 25.00 mL solution of 0.125 M acetic acid (Ka= 1.75 x 10^-5) after the addition of each of the following volumes of 0.100 M KOH: 10.00 mL, Vep and 35.00 mL
Sunday, April 21, 2013 at 9:25pm

General Chemistry
"How would you prepare 150. mL of 0.1M sodium hydroxide given a stock solution of 3.0M NaOH?" I made calculations and figured the process would be to dilute 5 mL of the 3.0M NaOH to 150. mL. Is this correct? For the ideal 150. mL of 0.1M NaOH, I calculated there to ...
Sunday, April 21, 2013 at 9:18pm

chemistry
If 10.4 liters of O2 at STP are produced by the electrolysis of water, how many coulombs of charge were required?
Sunday, April 21, 2013 at 8:42pm

chemistry
what will be the internal pressure causes by hydrogen gas when 5.00 g of zinc is dissolved in 50 g of concentrated hydrochloric acid if the volume of the container is 250 mL and the container is allowed to cool 20 degrees celcius
Sunday, April 21, 2013 at 8:34pm

Chemistry
What are the Six possible ratios for the equation for the formation of potassium chloride?
Sunday, April 21, 2013 at 8:02pm

Chemistry
What are the Six possible ratios for the equation for the formation of potassium chloride?
Sunday, April 21, 2013 at 8:00pm

Chemistry
Find the entropy change of the universe when 2 moles of water freezes at -10 degrees celsius. The delta G for the freezing of water at -10 degrees celsius is -210 J/mol and the heat of fusion of ice at this temperature is 5610 J/mol.
Sunday, April 21, 2013 at 7:02pm

Chemistry
Find the entropy change of the universe when 2 mol of water freezes at -10 degrees celsius.
Sunday, April 21, 2013 at 6:35pm

Chemistry
A solution contains 0.022 M Ag and 0.033 M Pb2 . If you add Cl–, AgCl and PbCl2 will begin to precipitate. What is the concentration of Cl– required, in molarity, when A. AgCl precipitation begins? B. AgCl precipitation is 99.99% complete? C. PbCl2 precipitation ...
Sunday, April 21, 2013 at 6:10pm

Chemistry
What [PB2+] should be maintained in Pb(NO3) to produce solubility of 1.0*10^-4 mol PbI2/L when PbI2 (s) is added? Ksp for PbI2 is 7.1*10^-9 I can't figure it out...
Sunday, April 21, 2013 at 5:44pm

Chemistry
Write an equation that represents how dihydrogen phosphate ion (H2PO4-) behaves as an Arrhenius acid. ( Be sure to include the correct charges for ions.)
Sunday, April 21, 2013 at 5:09pm

Chemistry
Write an equation showing that calcium hydroxide acts as an Arrhenius base in water. **(I'm not sure where to start or how to go about this question)
Sunday, April 21, 2013 at 2:55pm

Chemistry
Write the product for the reaction when dichlorine oxide (Cl_2O) reacts with water (the product will have only one equivalent of chlorine in it).
Sunday, April 21, 2013 at 2:26pm

Chemistry
Assume you dissolve 0.235 g of the weak acid benzoic acid, C6H5CO2H, in enough water to make 4.00*10^2 mL of solution and then titrate the solution with 0.138 M NaOH. C6H5CO2H(aq) + OH-(aq) C6H5CO2-(aq) + H2O(l) Find concentration of Na+ at equivalence point.
Sunday, April 21, 2013 at 1:52pm

Chemistry
Calculate the H3O+ ion concentration and the pH at the equivalence point when 45.0 mL of 0.4000 M NH3 is mixed with 45.0 mL of 0.4000 M HCl. Ka=5.6x10-10
Sunday, April 21, 2013 at 1:40pm

chemistry
what is the h+ of a solution with a ph of 10 at 25 degree celsius
Sunday, April 21, 2013 at 1:12pm

AP chemistry
A concentration cell consists of the same re- dox couples at the anode and the cathode, with different concentrations of the ions in the respective compartments. Find the un- known concentration for the following cell. Pb(s) | Pb2+(aq, ?) || Pb2+(aq, 0.1 M) | Pb(s) Answer in ...
Sunday, April 21, 2013 at 1:00pm

chemistry
in relation to the pH of pure water at 25 degree Celsius where do the pH values of acid fall
Sunday, April 21, 2013 at 12:44pm

Chemistry
A concentration cell consists of the same re- dox couples at the anode and the cathode, with different concentrations of the ions in the respective compartments. Find the un- known concentration for the following cell. Pb(s) | Pb2+(aq, ?) || Pb2+(aq, 0.1 M) | Pb(s) Answer in ...
Sunday, April 21, 2013 at 12:23pm

Chemistry
Please help!:( What mass of copper would be produced by the reduction of copper(II) ions during pas- sage of 1 ampere of current through a solution of copper(II) sulfate for 89 minutes?
Sunday, April 21, 2013 at 12:20pm

organic chemisty
write raction of benzoic acid with propylamine
Sunday, April 21, 2013 at 10:05am

chemistry
A 2.5 g sample of NaOH (Mw = 40.00) was dissolved in water to give a solution of final volume 250 cm3. (i) With reasons, state whether NaOH is a strong or a weak base. Give the conjugate acid of NaOH and decide whether this conjugate acid is acid, alkaline or neutral. (ii) ...
Sunday, April 21, 2013 at 10:01am

Chemistry
what happens to a battery when it is "recharged"
Sunday, April 21, 2013 at 2:31am

Chemistry
Propose buffer components to hold a pH of 9.5, let the base have a concentration of 0.1 M show all work please
Sunday, April 21, 2013 at 1:35am

Chemistry
Propose buffer components to hold a pH of 3.5, let the acid have a concentration of 0.1 M show all work
Sunday, April 21, 2013 at 1:33am

Chemistry
What is the solubility of Ca3(PO4)2 in 0.045 M of CaCl2
Sunday, April 21, 2013 at 1:29am

chemistry
What is the solubility of Ca3(PO4)2 in 0.06 M of K3PO4
Sunday, April 21, 2013 at 1:26am

Chemistry
4, Assign oxidation states for the two elements in the compound OF2. Explain the rules that you use. 5. For each of the following oxidation-reduction reactions of metals and nonmetals, identify the element that is oxidized and the element that is being reduced. a) 4Fe(s) + ...
Sunday, April 21, 2013 at 1:10am

Chemistry
Assign oxidation states to all atoms in each of the following. explain the order in which you determine the oxidation states for each element if applicable. a)O2 b)HSO4- c)Na2HPO4 d)CrCl3
Sunday, April 21, 2013 at 1:09am

Chemistry
What is the number of ATP molecules produced by the beta oxidation of eicosanoic acid?
Saturday, April 20, 2013 at 11:23pm

Chemistry
A marathon runner will burn 1.25x10^7 j during a race. If the calorie content of 12.0 oz. of Gatorade is 80.0 kilocalories, how many ounces of Gatorade must the runner drink to provide enough energy for the race? Note: 1 Calorie=4.184j and "kilo"= 10^3
Saturday, April 20, 2013 at 7:55pm

Chemistry
An alloy contains 39.5 mass% silver (Ag) and has density og 7.86 g/ml What volume of alloy would be needed to contain 12.0g of pure Ag?
Saturday, April 20, 2013 at 7:53pm

Chemistry
Could somebody please explain why in gaseous reaction the collision frequency between molecules is far greater than the rate at which molecules react? Thanks! :)
Saturday, April 20, 2013 at 3:20pm

chemistry
A car uses 114 g of petrol to travel one mile. Calculate the mass of carbon dioxide produced when this car travels one mile.
Saturday, April 20, 2013 at 2:26pm

Chemistry
Heating an ore of antimony (Sb2S3) in the presence of iron yields antimony and iron (II) sulfide. Sb2S3 + 3 Fe = 2Sb + 3 FeS When 15g of Sb2S3 reacts with 10g of Fe in the lab 9.84g of Sb is produced. What is the limiting reactant in this reaction? What is the theorectical ...
Saturday, April 20, 2013 at 12:14pm

chemistry
A 0.0583 mol sample of formaldehyde vapour, CH2O, was placed in a heated 0.359 L vessel and some of it decomposed. The reaction is CH2O(g)---> H2(g) + CO(g). At equilibrium, the CH2O concentration was 0.0449 M. What is the value of Kc for this reaction? my answer was 0....
Saturday, April 20, 2013 at 9:57am

chemistry
At high temperature, 2.00 mol of CH2O was placed in a 4.00 L container where it decomposed via the equilibrium CH2O(g)<=>CO(g)+H2(g) . At equilibrium, the concentration of CO was measured to be 0.0317 M. What is Kc for this reaction at this temperature?
Saturday, April 20, 2013 at 9:56am

chemistry
given that thee density of a supplied vinegar solution in an experiment is 1.025g/ml, what is the percentage acetic acid found in the vinegar sample?
Saturday, April 20, 2013 at 7:28am

chemistry
what is the solid remains in lithium trioxonitrate v
Saturday, April 20, 2013 at 5:58am

chemistry
reaction of benzoic acid with propylamine. if there no reaction why
Saturday, April 20, 2013 at 2:35am

Chemistry
You are measuring the concentration of Fe2 in a sample by measuring the absorbance of its complex with ferroxine. Your sample, measured in a 1.00-cm pathlength cuvette, has an absorbance of 0.347 while the reagent blank in the same cuvette has an absorbance of 0.040. What ...
Saturday, April 20, 2013 at 2:11am

chemistry
How many grams of NaCl must be added to 225.0 g of H2O at 45 °C to lower the vapor pressure of water by 2.21 mmHg? The vapor pressure of pure water is 71.93 mmHg at 45 °C.
Saturday, April 20, 2013 at 1:21am

chemistry
what is the change in temperature if 24g of water at 50 degrees C absorbs 985j of heat energy
Friday, April 19, 2013 at 10:19pm

chemistry
How many mL of 0.100M HCl are needed to neutralize 49.0mL of 0.104M Ba(OH)2 solution?
Friday, April 19, 2013 at 10:07pm

Chemistry - radioactivity
Hello Dr.Bob. Could you check my work please? I'm not sure if I'm right in how I solved this problem. Which of the following nuclides are most likely to decay via beta decay? A) I-131 B) Pb-206 C) F-18 D) Zr-90 E) Ar-40 I know that nuclides undergo beta decay when they...
Friday, April 19, 2013 at 8:28pm

Chemistry - electron configuration
Hello Dr.Bob. Could you please take a look at the following question? I know the correct answer for it, but I'm not sure how to go about solving it. Which ground state electronic configuration will most readily ionize to a 2 + cation? A) 1s22s22p63s23p64s23d10 B) ...
Friday, April 19, 2013 at 8:24pm

chemistry
two tables containing electron impact mass spectra data are shown. select the molecule that corresponds to the appropriate spectrum A) m/z: 29 57 86 B) m/z: 43 71 86 options for both 3-methyl-2-butanone, 3-pentanone, acetone, benzene
Friday, April 19, 2013 at 7:23pm

chemistry
Balance the following redox reaction by inserting the appropriate coefficients. H^+ +CrO4^2- +NO 2^- =Cr^3+ +H2O+NO3^-
Friday, April 19, 2013 at 4:25pm

Chemistry
Determine how many milliliters of 0.370 M HClO4 will be required to neutralize 58.99 g Ca(OH)2 according to the reaction: 2HC1O4+Ca(OH)2>CaC1O4)2+2H2O How would I set this up?
Friday, April 19, 2013 at 4:20pm

chemistry
If a solution containing 34.576 g of mercury(II) perchlorate is allowed to react completely with a solution containing 10.872 g of sodium sulfate, how many grams of solid precipitate will be formed?
Friday, April 19, 2013 at 4:04pm

chemistry
Baking soda is sodium bicarbonate, NaHCO3, and vinegar is primarily acetic acid, HC2H3O2. When baking soda is added to vinegar, the resulting reaction produces a tremendous amount of gas, as shown in this video. Complete this equation for the reaction of NaHCO3(s) with HC2H3O2...
Friday, April 19, 2013 at 3:56pm

chemistry
Write the net ionic equation (including phases) that corresponds to Fe(ClO4)2(aq)+Na2S(aq)=FeS(s)+2NaClO4(aq)
Friday, April 19, 2013 at 3:19pm

Chemistry
What is the (a) molality, (b) freezing point, and (c) boiling point of a solution containing 2.29 g napthalene (C10H8) in 44.6 g of benzene (C6H6)?
Friday, April 19, 2013 at 2:07pm

Chemistry
Find the pH of each mixture of acids 1) 0.115M in HBr + 0.125M in HCHO2 2) 0.050M in acetic acid + 0.050M in hydrocyanic acid
Friday, April 19, 2013 at 1:02pm

chemistry
A gas with a volume of 4.20 L at a pressure of 0.63 atm is allowed to expand until the volume raises to 95 L. What is the new pressure (in atm)?
Friday, April 19, 2013 at 12:34pm

Science-Chemistry
Methyl amine is a weak base with a pKb=3.35. Consider the titration of 30.0mL of .030M of Methyl amine with 0.025M HCl. a) Write the appropriate equation for the reaction. b) Calculate K for the reaction in part (a). c) Calculate pH of the initial methyl amine solution (0mL ...
Friday, April 19, 2013 at 11:44am

Chemistry
Calculate the [H+] for: black coffee with a pH of 6.9 (Enter your answer as follows: 1.0E-2 for 0.010)
Friday, April 19, 2013 at 10:32am

Chemistry
The structures of NO and NO2 possess similarity to free radicals. How are they similar in electronic terms?
Friday, April 19, 2013 at 8:32am

chemistry
A reaction produced 0.40 mmol of H in a buffered solution which contained 300ml of 0.06M succinate buffer, pH is 4. What was the pH of the medium after the reaction was completed? The pKa of succinate buffer is 4.21
Friday, April 19, 2013 at 4:13am

chemistry
To what volume should 100ml of any weak acid (HA) with a concentration of 0.2M be diluted to double the percentage ionization?
Friday, April 19, 2013 at 4:08am

chemistry
Predict the first order splitting patterns of the indicated proton in the following molecules: CH3CH2CH3 (the H in CH2 is selected) a) quintet b) quartet of quartets c)septet
Friday, April 19, 2013 at 1:19am

Chemistry
The of hydroxylamine, , is . A buffer solution is prepared by mixing 120 of a 0.34 hydroxylamine solution with 60 of a 0.25 solution.Solve for the PH
Friday, April 19, 2013 at 1:03am

Chemistry
A 17.6ml sample of a monoprotic acid is titrated with 0.212M NaOH. If 69.2ml of base is required to reach the equivalence point, what is the concentration of the acid?
Friday, April 19, 2013 at 12:56am

Chemistry
What is the pH of a solution prepared by mixing 25.00 mL of 0.10 M CH3CO2H with 25.00 mL of 0.030 M CH3CO2Na? Assume that the volume of the solutions are additive and that a = 1.8 × 10-5 for CH3CO2H.
Friday, April 19, 2013 at 12:39am

Chemistry
Consider the dissolution of CaCl2. CaCl2(s) Ca2+(aq) + 2 Cl-(aq) ÄH = -81.5 kJ A 10.4-g sample of CaCl2 is dissolved in 102 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 ...
Thursday, April 18, 2013 at 11:51pm

Chemistry
How much water must be added to 6 mL of a 0.05M stock solution to diltue it to 0.02M ? The answerI got is 15 mL. Is this correct? Thanks
Thursday, April 18, 2013 at 10:53pm

chemistry
Calculate the compositionof the gaseous mixture obtained when 1.25 mol f carbon dioxide is exposed to hot carbon at 800 degree celcius in a 1.25 liter vessel. The equilbrim constant kc at 800 degree celcius is 14 for the reaction CO2 + C = 2C0
Thursday, April 18, 2013 at 9:52pm

chemistry
calculate the yield of CO2 if 30.g of C2H6 reacts with 14.0g of O2. Show work
Thursday, April 18, 2013 at 9:29pm

Chemistry
Given the reaction: 4NH3+5O2--->4NO+6H2O When 1.20 moles of ammonia reacts, the total number of moles of products formed is: ?
Thursday, April 18, 2013 at 7:50pm

chemistry
what is the word and balanced chemical equation for oxalic acid and marble?
Thursday, April 18, 2013 at 7:49pm

chemistry
which metal react most vigorously? metals aluminum, copper, magnesium, lead, tin, zinc 1. which metal will react most quickly? 2. which will take the longest time to react? 3. which will react most vigorously and least vigorously? 4. list metals from order of least to most ...
Thursday, April 18, 2013 at 7:47pm

chemistry
When 24.2 kg of Fe2O3 react with 14.5 kg of CO and 5.4 kg of Fe are recovered, what is the percent yield for the reaction?
Thursday, April 18, 2013 at 7:28pm

chemistry
if the amount of radioactive iodine-123 in a sample decreases from .400g to .100g in 26.2 hours, what is the half-life of iodine-123
Thursday, April 18, 2013 at 7:23pm

Chemistry
A 19.9mL volume of a hydrochloric acid solution reacts completely with a solid sample of magnesium carbonate, producing 183mL of CO2 that is collected over water at 24.0 degrees C and 738 torr total pressure. The vapor pressure for water at 24.0 degrees C is 22.39 mmHg. What ...
Thursday, April 18, 2013 at 7:18pm

chemistry
What is the charge carried by electrons as 0.120 mole of Cr(s) is oxidized to Cr3+(aq)?
Thursday, April 18, 2013 at 6:41pm

Chemistry
What are the healthcare applications of biochemical, pharmaceutical and diagnostic chemical reactions?
Thursday, April 18, 2013 at 5:42pm

chemistry
wat chemical reactions are considered to be of importance to healthcare professionals? describe rational.
Thursday, April 18, 2013 at 5:39pm

Chemistry
Write the balanced chemical equation for reaction the following chemical reaction ozone gas , O3 , reacts with 2,3,4,5-tetramethylheptane, CH3-CH(CH3)-CH(CH3)-CH(CH3)-CH(CH3)-CH2-CH3 , to produce carbon dioxide gas, CO2 , and water vapor, H2O
Thursday, April 18, 2013 at 4:29pm

Chemistry
Nitrosyl bromide, NOBr, readily dissociated according to the following equilibrium equation: 2 NOBr (g) ----> 2 NO(g) + Br2 (g) NOBr was placed in a 1.00 L flask at 25.0oC and allowed to dissociated. At equilibrium, 0.17 moles of Br2 are obtained. If NOBr is found to be 34....
Thursday, April 18, 2013 at 4:16pm

chemistry
According to the reaction NaOH + HCl ¨ NaCl + H2O, which is the limiting reactant when 37.0 g of HCl are mixed with 37.0 g NaOH?
Thursday, April 18, 2013 at 4:13pm

Chemistry
Wood fragments from the floor of a palace in Syria - Syro-Hittite period. Date: 675 ± 50 years BCE , 1950 is present. PLEASE HELP!
Thursday, April 18, 2013 at 4:02pm

chemistry
The pressure in a 2.5 L container is 755.6 torr. If the volume increases to 3.6 L, what is the new pressure?
Thursday, April 18, 2013 at 3:59pm

Chemistry - molecular polarity
Hi Dr. Bob. Could you please take a look at the question below and my work? I'm not sure how to get the correct answer for this question. I would greatly appreciate your help! How many of the following molecules are polar? BrCl3 CS2 SiF4 SO3 A) 1 B) 2 C) 3 D) 4 E) 0 The ...
Thursday, April 18, 2013 at 3:45pm

Science(Chemistry)
Suppose that 23 mL of 0.6 M K2CrO4(aq) reacts with 13.7 mL of AgNO3(aq) completely. What mass of NaCl is needed to react completely with 38.5 mL of the same AgNO3 solution? Answer in units of g
Thursday, April 18, 2013 at 2:33pm

chemistry
The number of moles of o2 in 45.0L} of 02} gas.
Thursday, April 18, 2013 at 2:28pm

chemistry
Which of the following statements about boiling points are true? A. The boiling point of 0.1 m NaF(aq) is lower than the boiling point of 0.1 m methanol(aq). B. The boiling point of a 0.5 m aqueous solution of LiOH is the same as the boiling point of a 0.5 m aqueous solution ...
Thursday, April 18, 2013 at 1:37pm

Chemistry
What method of purification is used to separate iodoethane from traces of hydrogen iodide? Thanks :)
Thursday, April 18, 2013 at 1:35pm

Chemistry
On strong heating, 12g of NaHSO4 release 0.9g of water vapour and a white solid is left. Deduce a chemical formula for the solid. How can I work this out? Thanks :)
Thursday, April 18, 2013 at 12:52pm

chemistry
If 275 mL of hydrogen gas is produced at STP, what is the mass of lithium that reacted
Thursday, April 18, 2013 at 11:45am

Chemistry
A student uses 57.4 ml of 0.2m of RbOH to titrate 25.0ml of HcLo3. What is the concentration of HcLo3?
Thursday, April 18, 2013 at 11:34am

chemistry
You are studying the formation of HI(g) from its gaseous elements H2(g) and I2(g). The free energy of formation of HI(g) is –10.10 kJ/mol at 500 K. When the free energy change of the process at 500 K is zero, the reaction mixture shows partial pressures of HI and I2 as 10...
Thursday, April 18, 2013 at 11:03am

Chemistry
Nitrogen dioxide, a pollutant in the atmosphere, can combine with water to from nitric acid. One of the possible reactions is shown below. Calculate ∆G0 and Kp for this reaction at 25oC and comment of on the spontaneity of the reaction (MUST plot the data and find ...
Thursday, April 18, 2013 at 11:02am

chemistry
Consider the following reaction: I2(g) + Cl2(g) 2ICl(g) o Kp = 81.9 at 25 C. Calculate ∆Grxn for the reaction at 25 C under each of the following conditions: a Standard conditions. b At equilibrium. c PICl = 2.55 atm; PI2 = 0.325 atm; PCl2 = 0.221 atm.
Thursday, April 18, 2013 at 10:59am

Chemistry
Calculate ∆Ssurr when a reaction having each of the following changes in enthalpy: a. ∆Hrxn0 = -287 kJ; 298 K. b. ∆Hrxn0 = 127 kJ; 77 K.
Thursday, April 18, 2013 at 10:55am

chemistry
V1 = 0.55 L, P1 = 740 mm Hg, V2 = 0.79 L, P2 = ?
Thursday, April 18, 2013 at 10:20am

Chemistry
Four particles have free access to distribute into four different energy levels 0,5,10, and 20J. If these four particles are to create two macrostates having total energies 10J and 40J, which macrostate has more entropy?
Thursday, April 18, 2013 at 10:12am

chemistry
Suppose you do not know the enthalpy of decomposition of the process: CaCO3 = CaO + CO2 Explain in terms of thermodynamic parameters why heating to a high temperature might turn this decomposition to a spontaneous process.
Thursday, April 18, 2013 at 10:10am

Chemistry
Mopping the floor in a dry weather makes the floor dry quickly although detlaG0 for the water vaporization at room temperature is positive. Explain.
Thursday, April 18, 2013 at 10:07am

chemistry
Explain why exothermic processes are mire likely spontaneous when temperature of the system is low?
Thursday, April 18, 2013 at 9:55am

Chemistry
Entropy is a thermodynamic quantity that predicts the spontaneity of a reaction. Is this statement always true? Explain your answer with meaningful arguments. I assume the answer is no, but I cannot give a meaningful reason.
Thursday, April 18, 2013 at 9:53am

Chemistry
An exothermic reaction is spontaneous above 400K but non spontaneous below it. Of the deltaH for the reaction is -40.0 kcal, what are the values of deltaS and deltaG at 400K?
Thursday, April 18, 2013 at 9:52am

Chemistry
What is a supernatant
Thursday, April 18, 2013 at 7:01am

CHEMISTRY
after starting with 0.343g Al and excess HCl the volume of H2 gas collected over water was 472ml. the atmospheric pressure was 754 mmHg and the temp was 21c. 1 balanced chemical equation? 2calculate the pressure in atm of dry hydrogen gas in a mixture
Thursday, April 18, 2013 at 6:39am

Chemistry College
If KHP sample 1 requires 22.47 mL of aqueous NaOH, how many milliliters of NaOH should be needed for samples 2 and 3?
Thursday, April 18, 2013 at 3:59am

College Chemistry
When determining the vapor pressure of water, the bubble volume is 1.2mL at 5 degrees celsius. -How many moles of dry air were in the bubble? (assume 1 atm) -If the bubble volume is 8.6mL at 75 degrees celsius, what is the partial pressure of the dry air at this temp?
Thursday, April 18, 2013 at 2:16am

Chemistry
You are given the following decomposition reaction of ammonia NH3 ---> H2 + N3 unbalanced When you decompose 12.0g of NH3you produce 1.87 g of H2 Calculate the percent yield of H2
Thursday, April 18, 2013 at 2:07am

Chemistry
some ammonia gas is dissolved in water. The exact concentration of the solution is unknown and has to be determined. Describe an experiment that would determine the concentration of the aqueous ammonia.
Thursday, April 18, 2013 at 2:06am

chemistry
When sodium is heated with sulfur,sodium sulfide is product. What mass of sodium sulfide can be formed by heating 12.8 g of sulfur with 9.2g of sodium?
Thursday, April 18, 2013 at 1:51am

chemistry
how many gram of h2 needed to react with 3.10 n2
Thursday, April 18, 2013 at 1:43am

chemistry
how many gram of h2 needed to react with 3.10 n2
Thursday, April 18, 2013 at 1:42am

chemistry
Hey guys please help me answer these chemistry questions.? 1. can a strong acid be diluted. explain in detail 2. can a weak acid be diluted. explain in detail 3. how does your observation of sunlight change when you place two different concentrations of food colored solution ...
Thursday, April 18, 2013 at 1:10am

chemistry
how to prepare 24 μL of 5% H3BO3
Thursday, April 18, 2013 at 12:34am

Chemistry
What is the equation for the reaction of potassium soap with HCL?
Thursday, April 18, 2013 at 12:08am

Chemistry
In saponification, does sudsing show after adding acid. Why?
Thursday, April 18, 2013 at 12:05am

Chemistry
What is the pH of a buffer system that contains 0.18M NH4+ and 0.14M NH3? The pKa of NH4+ is 9.25.
Thursday, April 18, 2013 at 12:02am

Chemistry
2 moles of helium (He) are pumped from a gas canister into a weather balloon. The balloon at this point has a volume V1. 1 mole of nitrogen gas (N2) is added at the same temperature and pressure. The volume of the balloon changes to V2. How will the new volume of the balloon ...
Wednesday, April 17, 2013 at 11:38pm

chemistry
what is the effect of barium chloride solution, dilute hydrochloric acid and dilute trioxonitrate(v) acid on iron II ammonium sulphate hexahydrate
Wednesday, April 17, 2013 at 11:27pm

chemistry
effect of Bacl2 and HNO3 of (NH4)2so4.feso4.6ho2
Wednesday, April 17, 2013 at 11:12pm

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