Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

chemistry
A solution of ethanol, C2H5OH, is prepared by dissolving 25.0 mL of ethanol in enough water to give a total volume of 250.0 mL. What is the percent-by-volume concentration of ethanol?
Friday, May 10, 2013 at 10:44pm

CHEMISTRY
The two half-reactions for the LeClanche dry cell battery are shown below. Describe the direction of spontaneous electron flow in this electrochemical cell. Zn(s) ---> Zn2+(aq) + 2e- 2NH4+(aq) + 2e- ---> 2NH3(g) + H2(g)
Friday, May 10, 2013 at 6:13pm

Chemistry
77.0 mL of a 1.20 M solution is diluted to a total volume of 288 mL. A 144-mL portion of that solution is diluted by adding 155 mL of water. What is the final concentration? Assume the volumes are additive.
Friday, May 10, 2013 at 5:42pm

Chemistry pH
What is the pH of a solution that is .60 M H2SO4 (Sulfuric acid) and 1.7 M HCOOH (formic acid).
Friday, May 10, 2013 at 1:55pm

CHEMISTRY Homework Assignment
Hi I noticed someone else put this question up, but I am having a hard time with this one. I HAVE NO IDEA WHAT TO DO. What will be the products of the electrolysis of an aqueous solution of zirconium iodide (ZrI4)? (The electrodes themselves are platinum.)
Friday, May 10, 2013 at 12:23pm

CHEMISTRY Homework
What will be the products of the electrolysis of an aqueous solution of zirconium iodide (ZrI4)? (The electrodes themselves are platinum.)
Friday, May 10, 2013 at 12:00pm

Chemistry Question
Calculate the ∆G˚ for the oxidation of nickel in the following balanced reaction. 2[RhCl6]3-(aq)+ 3Ni a 2Rh(s) + 3NiCl2(aq) + 6Cl-(aq) E˚ for RhCl6 is 0.5V E˚ for Ni(s) is -0.25V
Friday, May 10, 2013 at 10:39am

College Chemistry 104
Students are attempting to construct a battery in the laboratory that will light up a light bulb. Compare the following lists prepared by students and determine which student will not be able to successfully build a "battery" that will light up the bulb. Student 1 ...
Friday, May 10, 2013 at 10:28am

chemistry
When heated, elemental phosphorus, P4, produces phosphine, PH3, and phosphoric acid, H3PO4. How many grams of phosphine are produced if 56 grams of P4 have react
Friday, May 10, 2013 at 10:27am

Chemistry
under the same conditions of temperature and pressure , does hydrogen iodide and ammonia diffuse faster? calculate the ratio of the velocities
Friday, May 10, 2013 at 8:40am

chemistry
for an aqueous solution having Calcl2 (2molar) and Mgcl2 (5molal) and specified gravity of solution is 1.145 calculate molality of chloride ion and molality if chloride ion.
Friday, May 10, 2013 at 4:54am

Chemistry Help Please
Which pair of ions will be most likely to react at standard state conditions? a) MnO4- and Sn2+ b) Zn2+ and Cl- c) I- and Cu d) Fe3+ and Cu2+
Thursday, May 9, 2013 at 11:47pm

Chemistry
What's is the concentration of silver ions in a saturated solution of silver carbonate? The k^sp of Ag2CO3 is 8.1x10^ -12. Is the answer 5.88x10^-8? I have a test tomorrow and I really need to make sure I'm doing these problems right, but I feel like I am not.
Thursday, May 9, 2013 at 10:56pm

Chemistry
Name the compounds CH3CH2CHCH2CH3 - Is this 3-Pentane? Thanks
Thursday, May 9, 2013 at 10:06pm

Chemistry
What is the molarity of a solution prepared by dissolving 5.86 grams of naoh in enough water to make 250 milliliters of solution
Thursday, May 9, 2013 at 4:35pm

Chemistry
1.What mass of NaOH(s) must be added to 300 mL of HCl 0.25 M in order to completely neutralize this acid? 2.During a lab, you mix 2 solutions: a 100 ml solution containing 0.40 g of NaOH and a 100 mL solution containing 0.73 g of HCl. What is the concentration of H+ ions in ...
Thursday, May 9, 2013 at 2:22pm

chemistry
The surface tension versus log concentration for two surfactants is shown below. Describe in no more than five sentences how the two surfactants can be so different. You have only one attempt at this problem.
Thursday, May 9, 2013 at 1:43pm

chemistry
A volume of 50.0 ml of gas is collected by displacement of mercury at 17 degrees Celsius and 760 mm pressure. The mercury level inside the eudiometer is 30.0 mm higher than the outside. What volume will the gas occupy at STP?
Thursday, May 9, 2013 at 11:53am

chemistry
a)Calculate the pH of a solution of 0.75 M HNO3, which is a strong acid. b)Calculate the pH of a 1.0 L aqueous solution made from 0.80 mol CH3COOH and 0.20 mol KCH3COO (Ka = 1.8 x 10^-5).
Thursday, May 9, 2013 at 9:36am

CHEMISTRY
how would a chemistry student make a 600 mL of 1.5 M solution of NaBr?
Thursday, May 9, 2013 at 4:21am

chemistry
A mixture consisting of 0.150 M N2(g) and 0.612 M H2(g) reacts and then reaches equilibrium according to the equation: N2(g) + 3H2(g) ⇋ 2NH3(g) At equilibrium, the concentration of ammonia is 0.213 M. Calculate the concentration (molarity) of H2(g) at equilibrium to 3 ...
Thursday, May 9, 2013 at 3:56am

Chemistry Help Please
Which of the following is the strongest reducing agent? a) Li+ b) Zn c) Sn d) H2 Is it Li? Can someone please explain what the answer is and why?
Thursday, May 9, 2013 at 2:48am

chemistry
a gas occupies 37.6 L at 2.00 atm pressure and 27C degrees. how many moles of gas are present in this sample
Wednesday, May 8, 2013 at 9:40pm

chemistry
a sample of oxygen gas has a volume of 7.64 L at a temperature of 19C and a pressure of 1.38 atm. Calculate the moles of O2 present in this gas sample
Wednesday, May 8, 2013 at 9:38pm

chemistry
11.During an acid-base titration, 25 mL of NaOH 0.2 M were required to neutralize 20 mL of HCl. Calculate the pH of the solution for each of the following: 12.Before the titration. 13.After adding 24.9 mL of NaOH. 14.At the equivalence point. 15.After adding 25.1 mL of NaOH. ...
Wednesday, May 8, 2013 at 9:18pm

Chemistry
How many moles of potassium hydroxide are required to neutralize 1.25 mol of phosphoric acid? H3PO4 + 3KOH -> K3PO4 +3H2O I got 0.42 mol KOH , is this correct? thanks!
Wednesday, May 8, 2013 at 5:25pm

HELP! CHEMISTRY
Which one of the following species will react with Sn at standard state conditions? a) S b) Ag+ c) Cu d) Zn2+ What does it mean by standard state conditions? And what do I have to look at to determine it? Would it be Zn2+?
Wednesday, May 8, 2013 at 5:22pm

chemistry
A. Find and list all of the different half- cell combinations. Hint 15 combinations! 1. Copper/ Cu2+ 2. Lead/ Pb2+ 3. Magnesium/ Mg2+ 4. Zinc/ Zn2+ 5. Iron/Fe2+ 6. Aluminum/ Al3+ B. write the half reactions of each combination and the overall redox reaction. Please help! Thank...
Wednesday, May 8, 2013 at 3:45pm

Chemistry
A saturated solution of potassium nitrate in water is prepared at 70.0*C then cooled to 55.0*C how many grams of potassium nitrate crystallized--- how do I determine this using my graph with everyone's numbers
Wednesday, May 8, 2013 at 3:17pm

Chemistry
Consider a generic redox reaction then suppose that the coefficients in the redox reaction are doubled. How will the following quantities be affected for a voltaic cell under nonstandard conditions, will they be Doubled, Halved, Squared, or No Change. Note that n is written as...
Wednesday, May 8, 2013 at 1:43pm

chemistry
how to determine the oxalate and copper in K[Cu(C2O4)2].2H2O
Wednesday, May 8, 2013 at 11:49am

Ap chemistry
What is the approximate molar fraction of ethanol c2h5oh in an aqueous solution in which the ethanol concentration is 11.0 molal? A. 0.0011 B. 0.011 C. 0.170 D. 0.200 E. 0.600
Wednesday, May 8, 2013 at 10:11am

chemistry
Sodium dodecyl sulfate (SDS) has the structure below. The surface tension of water changes as SDS is added, as shown in the graph below. (a) Why does the surface tension of water change as SDS is added? The number of micelles increases, which allows the non-polar tails of SDS ...
Wednesday, May 8, 2013 at 9:05am

Chemistry
A beaker is filled with Ammonia (NH3) and Hexane. A surfactant with a polar head group and non-polar tail is added to the mixture, and the beaker is agitated and then allowed to equilibrate. The values of density are 0.65 g/cm3 for hexane and 0.60 g/cm3 for liquid ammonia. ...
Wednesday, May 8, 2013 at 8:44am

chemistry
if the endpoint in the tritration of the KHC8H4O4 solution with the NaOH solution is mistakenly surpressed(too pink),will the molar concentration of the NaOH solution be reported too high or too low?explain
Wednesday, May 8, 2013 at 4:27am

chemistry
please i need example of hno3 cuo
Wednesday, May 8, 2013 at 4:10am

chemistry
Consider the polymer polybutadiene. (a) Will linear polybutadiene or branched polybutadiene have a higher molar volume? (b) Will linear polybutadiene or branched polybutadiene have a higher glass transition temperature? (c) Will linear polybutadiene or branched polybutadiene ...
Wednesday, May 8, 2013 at 3:42am

Chemistry
Explain why iron corrodes more quickly in seawater than in freshwater. I'm getting conflicting answers from searching on Google; is it because the corrosion of iron is a redox reaction, which involves a transfer of electrons, and therefore this transfer of electrons would ...
Tuesday, May 7, 2013 at 11:27pm

chemistry
A sample of an ideal gas has a volume of 2.29 L at 2.90 × 102 K and 1.08 atm. Calculate the pressure when the volume is 1.57 L and the temperature is 302 K.
Tuesday, May 7, 2013 at 10:43pm

Chemistry
An antacid tablet containing magnesium hydroxide instead of calcium carbonate was dissolved in 100.0 mL of 0.2893 M HCL. 10 mL of this solutions was titrated to endpoint with 25.20 mL of 0.1007 M NaOH. How much magnesium hydroxide was in the antacid tablet(in mg)? Any help is ...
Tuesday, May 7, 2013 at 9:28pm

Chemistry
A gas occupying a volume of 664 mL at a pressure of 0.970 atm is allowed to expand at constant temperature until its pressure reaches 0.541 atm. What is its final volume?
Tuesday, May 7, 2013 at 9:27pm

Chemistry
The voltage generated by the zinc concentration cell described by, Zn(s)|Zn2 (aq, 0.100 M)||Zn2 (aq, ? M)|Zn(s) is 23.0 mV at 25°C. Calculate the concentration of the Zn2 (aq) ion at the cathode. Can someone please breakdown how to do this so I can figure out the rest of ...
Tuesday, May 7, 2013 at 6:31pm

chemistry
If the endpoint in the titration of KHC8H4O4 solution with the NaOH solution is mistakenly surpassed, will the molar concentration of NaOH solution be reported too high or too low?
Tuesday, May 7, 2013 at 3:27pm

chemistry
a stone is thrown vertically upwards from the edge of a tower with velocity 5m/s.it strikes the ground close to the base after 4s .the height of tower?
Tuesday, May 7, 2013 at 3:23pm

Chemistry
Explain, not just describe, the relationship between these rankings. Most reactive to least reactive metals: Zn, Pb, Cu, Ag Most reactive to least reactive metal cations: Ag, Cu, Pb, Zn
Tuesday, May 7, 2013 at 2:34pm

Chemistry
Which two elements is the second transition series (y through Cd) have four unpaired electrons in their 3+ ions?
Tuesday, May 7, 2013 at 1:40pm

Chemistry
An unknown solid acid is either citric acid or tartaric acid. To determine which acid you have, you titrate a sample of the solid with NaOH. The appropriate reactions are as follows: Citric acid: H3C6H5O7 (aq) + 3NaOH (aq) -> 3H2O (l) + Na3C6H5O7 (aq) Tartaric acid: ...
Tuesday, May 7, 2013 at 1:25pm

Chemistry
Estimate how many microwave photons with 1=12 cm must be absorbed to raise the temperature of your eye by 3 degree C. Assume the mass of an eye is 11 g and its specific heat capacity is 4.0 J/g/k
Tuesday, May 7, 2013 at 1:19pm

Chemistry
One chirality of CH3CHCICOOH is shown below. COOH | C H3C/ \CI - - - H Identify the image(s) below that excibit the opposite chirality. Select all that apply. (a) COOH (b) H | | C C _ | _ / \ _ | _ H3C CI _ | _ _ _ | _ _ CI | CH3 _ H COOH (c) CI (d) COOH | | C C / \ / \ H COOH...
Tuesday, May 7, 2013 at 1:04pm

Chemistry
A substance releases 496kJ of heat as 2.60 moles condense from a gas into a liquid. What is the molar heat of vaporization of the substance?
Tuesday, May 7, 2013 at 12:14pm

Chemistry
A voltaic cell consists of a Pb/Pb2+ half-cell and a Cu/Cu2+ half-cell at 25 C. The initial concentrations of Pb+2 and Cu+2 are 0.0500 M and 1.50 M, respectively. A. What is the initial cell potential? B. What is the cell potential when the concentration of Cu+2 has fallen to ...
Tuesday, May 7, 2013 at 11:54am

College Chemistry 104
A voltaic cell consists of a Pb/Pb2+ half-cell and a Cu/Cu2+ half-cell at 25 C. The initial concentrations of Pb+2 and Cu+2 are 0.0500 M and 1.50 M, respectively. A. What is the initial cell potential? B. What is the cell potential when the concentration of Cu+2 has fallen to ...
Tuesday, May 7, 2013 at 11:50am

Chemistry
What is the equilibrium constant for the reaction: Si + O2 <-> SiO2 ? Is the answer just [SiO2]/[Si][O2] ?
Tuesday, May 7, 2013 at 11:31am

chemistry
The density of CO2 (g) at 25°C and 715 torr is:
Tuesday, May 7, 2013 at 11:23am

chemistry
How many moles of sodium nitrate are in 0.65L of a 0.2 M NaNO solution?
Tuesday, May 7, 2013 at 7:58am

chemistry
what is the value of degree of polymerization of isotactic PB with a molecular weight of 3.091e5 g/mol
Tuesday, May 7, 2013 at 2:03am

chemistry
calculate the degree of polymerization of polystyrene with a molecular weight of 3.091e6 gm/mol
Tuesday, May 7, 2013 at 2:00am

chemistry
calculate the solubility product of leadchloride in pure water.your answer should be in units of molarity raised to the appropriate exponent.
Tuesday, May 7, 2013 at 1:46am

chemistry
the solubility of the fictitious compound administratium fluoride in water is 3.091e-4.calculate the value of solubility product ksp
Tuesday, May 7, 2013 at 1:40am

chemistry
calculate the enthalpy of mixing for the solution of 10% platinum and 90% gold .express your answer in units of kg/mole
Tuesday, May 7, 2013 at 1:15am

chemistry
Why would methanol be used to halt a secondary alcohol and catalyst reaction?
Tuesday, May 7, 2013 at 12:22am

chemistry
Why would methanol be used to halt a secondary alcohol and catalyst reaction?
Tuesday, May 7, 2013 at 12:21am

chemistry
Calculate the concentration of each solute and each ions when 25.0 mL of 18.0 M H2SO4 is mixed with 130.0 mL water
Monday, May 6, 2013 at 11:46pm

chemistry
how many grams of iron (iii) nitrate are needed to produce 25.0 g of iron (iii) sulfate form sulfuric acid?
Monday, May 6, 2013 at 11:22pm

chemistry
how many grams of carbon dioxide can be produced when 15.g of oxygen is reacted with 25.g of c2h2
Monday, May 6, 2013 at 10:47pm

chemistry
When boiled with concentrated aqueous alkali, fats and oils dissolve, but waxes do not. Explain the difference.
Monday, May 6, 2013 at 10:02pm

Chemistry
we burn 12.50L of ammonia in 20.00L of oxygen at 500 degrees celsius. What volume of nitric oxide, NO, gas can form? what volume of steam, H2O (g) is formed? Assume that all gases are at the same temperature and pressure, and that the limiting reactant is used up 4NH3(g) + 5O2...
Monday, May 6, 2013 at 8:00pm

Chemistry
For the following battery: Cd(s) | CdCl2(aq) || Cl–(aq) | Cl2(l) | C(s) (a) Write the reduction half-reaction occuring at the C(s) electrode. (Include physical states of reactants and products.) C(s) electrode:? (c) Calculate the mass of Cl2 consumed if the battery ...
Monday, May 6, 2013 at 5:48pm

Chemistry
Help please!!! Complete the two reduction half reactions for the cell shown at the right, and show the line notation for the cell by dragging labels to the correct position. (The electrode on the left is the anode, and the one on the right is the cathode.) Ag and Pb Anode half...
Monday, May 6, 2013 at 5:45pm

Chemistry
A salt solution is evaporated to dryness. If 66.5 g of the solution leaves 1,492 mg of dry salt, what is the percent concentration (w/w) of the salt in the solution?
Monday, May 6, 2013 at 3:57pm

Chemistry
A certain gas has a solubility of .50 g/L under a pressure of 1500 torr. What would its solubility be a 2250 torr?
Monday, May 6, 2013 at 3:55pm

Chemistry
Calculate the volume of 2.45 M NaI that would be needed to precipitate all of the Hg+2 ion from 185 mL of a 2.44 M Hg(NO3)2. AND Calculate the molarity of an acetic acid solution if 47.81 mL of the solution is needed to neutralize 147 mL of 1.32 M sodium hydroxide.
Monday, May 6, 2013 at 3:52pm

Chemistry HELP!
In order to standardize a KMnO4 solution, 0.3498 g Na2C2O4 was dissolved in 30 mL water and 15 mL 3.0 M H2SO4. The KMnO4 solution was added to the Na2C2O4 solution until a pale pink color persisted. The titration took 29.5 mL of KMnO4 solution. What is the concentration of ...
Monday, May 6, 2013 at 11:25am

chemistry
We have a tank that contains O2 at 146 mmHg, N2 at 146 mmHg, and CO2 at 138 mmHg. We then add 135 mmHg of Ar. What is the pressure in the tank?
Monday, May 6, 2013 at 11:13am

chemistry
The pKb of ammonia solution, NH3(aq) is 4.76. A buffer solution contains NH4Cl and NH3, has a pH of 9.45, and a total ammonia concentration (all forms) of 0.400 M. What is the concentration of NH4+? (Hint: [NH4+] + [NH3] = 0.400 M)
Monday, May 6, 2013 at 10:37am

chemistry
What is the difference between the two strong acids, nitric and hydrochloric acid, when they behave as the oxidised forms in a reduction half-equation?
Monday, May 6, 2013 at 8:24am

chemistry
determine the number of representative particles in each of the following and identify the representative particle: 11.5 mol Ag; 18.0 mol H20; 0.150 mol NaCL.
Monday, May 6, 2013 at 8:17am

chemistry
An ideal gas in a sealed container has an initial volume of 2.45 L. At constant pressure, it is cooled to 23.00 °C where its final volume is 1.75 L. What was the initial temperature?
Monday, May 6, 2013 at 1:52am

Chemistry
Why is this reaction considered exothermic? "Concentrated sulfuric acid dissolves in water and the solution becomes warmer." This is a homework question and when I answered the problem, I thought it was endothermic because the solution is gaining heat, but when my ...
Sunday, May 5, 2013 at 11:57pm

Chemistry PLEASE HELP!
Check all of the following statements which are TRUE for a titration. Select one or more: a. A suitable primary standard must be available. b. The concentration of the solution in the buret (the titrant) must be known before the titration is begun. c. Titrations can only be ...
Sunday, May 5, 2013 at 11:43pm

Chemistry
Use Hess's Law to find the change in heat of 2C(graphite)+H2(g)-->C2H2(g)? Given: C(graphite) + O2(g) --> CO2(g) change of heat rxn = -393.5 kJ 2H2 (g) + O2(g) ---> 2H2O (l) change of heat rxn = -571.6 kJ 2C2H2 (g) +5O2(g) ----> 4CO2(g) +2H2O (l) change of heat...
Sunday, May 5, 2013 at 10:54pm

Chemistry
How do you find the equilibrium constant of: B + O2 <-> BO2 ??
Sunday, May 5, 2013 at 9:40pm

chemistry
Using the following thermochemical data, what is the change in enthalpy for the following reaction? Ca(OH)¿(aq) + HCl(aq) d CaCl¿(aq) + H¿O(l) CaO(s) + 2HCl(aq) d CaCl¿(aq) + H¿O(l), DH = -186 kJ CaO(s) + H¿O(l) d Ca(OH)¿(...
Sunday, May 5, 2013 at 7:53pm

Chemistry
cr(s)--->Cr^3(aq)+3e- and Pb2+(aq)+2e---->Pb(s) write a balanced equation Please help thanks
Sunday, May 5, 2013 at 7:46pm

Chemistry
cd2+ (aq) +ni(s)---> cd(s) + ni2+ (aq) what is the half reaction
Sunday, May 5, 2013 at 6:24pm

Chemistry
cr(s)--->Cr^3(aq)+3e- and Pb2+(aq)+2e---->Pb(s) write a balanced equation Please help thanks
Sunday, May 5, 2013 at 6:23pm

Chemistry
How do you find the equilibrium constant? ..steps?
Sunday, May 5, 2013 at 6:09pm

Chemistry
So we're doing oxidation-reduction reactions and batteries and voltages. We did a lab where we would take two metals, put it in a mixture (bleach/water/vinegar/salt) and used a voltmeter to see the DC voltage. Now we're supposed to 'calculate the potential ...
Sunday, May 5, 2013 at 5:26pm

Chemistry
cd2+ (aq) +ni(s)---> cd(s) + ni2+ (aq) what is the half reaction
Sunday, May 5, 2013 at 5:12pm

chemistry
Complete the two reduction half reactions for the cell shown at the right, and show the line notation for the cell by dragging labels to the correct position. (The electrode on the left is the anode, and the one on the right is the cathode.) They give you 2AgCl(s); Pb(s); AgCl...
Sunday, May 5, 2013 at 4:34pm

chemistry
We have a tank that contains O2 at 146 mmHg, N2 at 146 mmHg, and CO2 at 138 mmHg. We then add 135 mmHg of Ar. What is the pressure in the tank?
Sunday, May 5, 2013 at 4:31pm

Chemistry
Given that 1g of Phenacetin requires 82mL of hot water to dissolve, or 1310mL of cold water (TY= 3.92g): 1) How much water will you need to recrystallize the theoretical yield? 2) How much product will be lost because of recrystallization?
Sunday, May 5, 2013 at 3:33pm

Intro Chemistry
Given: 2CO(g) + O2(g) -> 2C02(g). When 10 mol of CO and 8.0 mol of O2 react in a closed 10L vessel. a)how many moles of CO, O2, and CO2 are present at the end of the reaction? b)What will be the total pressure in the flask at 0 degrees C?
Sunday, May 5, 2013 at 1:08pm

Intro Chemistry
Given: C2H2(g) +2HF(g) -> C2H4F2(g) Find: pressure in a 10.0L flask when the reaction is complete When 1.0 mol of C2H2 and 5.0 mol pf HF are reacted in a 10.0 L flask, what will be the pressure in the flask at 0 degrees C when the reaction is complete?
Sunday, May 5, 2013 at 12:57pm

chemistry
Calculate the partial pressure of helium in a 1.00 L flask that contains equal numbers of moles of He, Ne, and Ar at a total pressure of 8.35 atm.
Sunday, May 5, 2013 at 12:33pm

Chemistry 104 PLEASE HELP ME!!
Determine the weight of Na2C2O4 which is required to react completely with 20.0ml of 0.02M KMnO4.
Sunday, May 5, 2013 at 12:05pm

college Chemistry
What would you expect to be the chemical names of the main gases that were dissolved in the tap water?
Sunday, May 5, 2013 at 11:54am

CHEMISTRY
WHEN DOES A CHEMICAL BECOME A DRUG?
Sunday, May 5, 2013 at 11:54am

chemistry
a 35.0ml sample of 37% hcl solution has a density of 1.18g/ml. the sample is diluted to a volume of 0.125L. what is the molarity of the final solution ?
Sunday, May 5, 2013 at 11:54am

college Chemistry
Conductivity test, what controls the brightness of the light? (hint: think about your tapwater abd NaCl results and why they were different)
Sunday, May 5, 2013 at 11:37am

chemistry
WHEN DOES A CHEMICAL BECOME A DRUG?
Sunday, May 5, 2013 at 11:28am

chemistry
a 35.0ml sample of 37 hcl solution has a density of 1.18g/ml. the sample is diluted to a volume of 0.125L. what is the molarity of the final solution ?
Sunday, May 5, 2013 at 10:46am

College Chemistry
What must we know a given ionic salt to be able to predict whether is is a good or poor conductor, w/o testing its conductivity?
Sunday, May 5, 2013 at 10:32am

Chemistry
one morning you are given 3 test tubes of aqueous solutions of compound X: the "A" tube was set up as unsaturated, while "B" was set up as Saturated in a beaker, then poured of into the tube, and "C" was carefully set up as supersaturated. At ...
Sunday, May 5, 2013 at 10:28am

Chemistry
What must we know a given ionic salt to be able to predict whether is is a good or poor conductor, w/o testing its conductivity?
Sunday, May 5, 2013 at 10:15am

chemistry
The percent water in methyl alcohol can be determined by gas chromatography using a capillary column coated with a non-polar stationary phase and a thermal conductivity detector. A series of calibration standards yielded the following results: Water content (% w/w) Peak height...
Sunday, May 5, 2013 at 9:29am

chemistry
A manometer attached to a flask contains NH3 gas have no difference in mercury level initially as shown in diagram. After the sparking into the flask, it have difference of 19 cm in mercury level in two columns. Calculate % dissociation of ammonia. (1) 21% (2) 22% (3) 24% (4...
Sunday, May 5, 2013 at 6:00am

chemistry
When does a chemical become a drug?
Sunday, May 5, 2013 at 5:32am

chemistry
the fictitious compound pandemonium carbonate has a ksg=3.091*10^-9 M 3 in water at poor temperature .calculate the solubility of PnCo3 in an aqueous solution of 1.11 M pandemonium sulfate. express your answer in units of molarity.
Sunday, May 5, 2013 at 4:35am

chemistry
the fictitious compound pandemonium fluoride has a k value in water of 3.091*10^-9 M^3.calculate the solubility of PnF2 in water. Express your answer in units of molarity.
Sunday, May 5, 2013 at 4:24am

Chemistry
10cm^3 of aa hydrocarbon was completely combusted in 200cm^3 of O2. It was found that there was 20cm^3 of O2 remaining and the volume of CO2 produced was 120cm^3. Determine the formula of the hydrocarbon.
Sunday, May 5, 2013 at 3:25am

Chemistry
The density of concentrated sulfuric acid is 1.84 g/mL. If this corresponds to 18 M, what is the molality of the solution? Molar mass= 98. 98 x 18 =1764g/L - 1.84 =1762.16/1000 = 1.76 kg 18/1.76=10.23 m But my only options are: a) 18 m b) 95.5 m c) 240 m d) 0.240 m?
Sunday, May 5, 2013 at 2:34am

Chemistry
When 100.0 g of an unknown nonelectrolyte is dissolved in 500.0 g of benzene, C6H6, the solution boils at 82.9°C. Calculate the molecular weight (molar mass) of the unknown material. Kb for benzene is 2.53°C/m and the boiling point of pure benzene is 80.1°C?
Sunday, May 5, 2013 at 2:04am

Chemistry
why is it important to know accurately the mass of water used in a calorimeter?
Sunday, May 5, 2013 at 1:00am

analytical chemistry
A solution containing both Fe 3+ and Al 3+ can be selectively analyzed for Fe 3+ by buffering to a pH of 2 and titrating with EDTA. Th e pH of the solution is then raised to 5 and an excess of EDTA added, resulting in the formation of the Al 3+ - EDTA complex. The excess EDTA ...
Saturday, May 4, 2013 at 9:36pm

chemistry
Helium-oxygen mixtures are used by divers to avoid the bends and are used in medicine to treat some respiratory ailments. What percent (by moles) of He is present in a helium-oxygen mixture having a density of 0.528g/L at 25 degree celsius and 721 mmHg ?
Saturday, May 4, 2013 at 7:39pm

chemistry
To identify a diatomic gas (), a researcher carried out the following experiment: She weighed an empty 2.4- bulb, then filled it with the gas at 1.70 and 28.0 and weighed it again. The difference in mass was 4.7 . Identify the gas.
Saturday, May 4, 2013 at 7:33pm

Chemistry
Assuming equal concentrations, rank these aqueous solutions by their freezing point: low to high NH4Cl, Sn(ClO3)4, Na2SO4, and AlBr3.
Saturday, May 4, 2013 at 6:52pm

chemistry
enzymes convert glucose M=180.2 to ethanol M=46.1 according to the equation C6H12O6=2C2H5OH + 2CO2 what is the maximum mass of ethanol that can be made from 15.5 kg of glucose?
Saturday, May 4, 2013 at 4:46pm

Chemistry
what is the final volume of 1% KOH soltion prepared from a 10ml of a 20% KOH solution?
Saturday, May 4, 2013 at 4:21pm

chemistry
Calculate the pH of the following solutions. (A) 0.95 NaOH (B) 9.9x10^-10 M NaOH (C) 6.7 M NaOH
Saturday, May 4, 2013 at 2:02pm

chemistry
find the molar solubility of zinc carbonate if its ksp=1.5x10^-10. (at 298K)
Saturday, May 4, 2013 at 11:43am

Chemistry
What is the mass of ethylene gycol dissolved in 5.00 kg of a 40.0% solution?
Saturday, May 4, 2013 at 11:41am

Science - Chemistry
I need help I've got 2 books and they both tell me different things. I need to know the 3 different ways of extracting salt, how it's done, the advantages and the disadvantages of each one?? Please Help!!!
Saturday, May 4, 2013 at 11:11am

chemistry
does kh2po4 react with sodium lauryl sulphate and can we use nah2po4 insted of kh2po4 in prepration of 0.2 m phosphate buffer ?
Saturday, May 4, 2013 at 7:45am

chemistry
Would you expect the solubility of PbCl2 in water to change dramatically if it were to be dissolved into a solution of 3.091×10−4 M KCl? Yes, the solubility of PbCl2 would decrease dramatically. Yes, the solubility of PbCl2 would increase dramatically. No, the ...
Saturday, May 4, 2013 at 6:25am

chemistry
Consider the gold-platinum system which has a value of delta w of -4250 J/mole; (a) Calculate the enthalpy of mixing for a solution of 10% platinum and 90% gold. Express your answer in units of kJ/mole. (b) Is the dissolution of 10% platinum into gold an endothermic or an ...
Saturday, May 4, 2013 at 6:24am

CHEMISTRY
1.AN ORBITAL can have at the most two electrons of opposite spine can be called ?
Saturday, May 4, 2013 at 3:58am

chemistry
what is a titration, what is the type of reaction to find the volume of hydrochloric acid needed to react with 25 of potassium hydroxide solution
Saturday, May 4, 2013 at 3:19am

Chemistry
What is the Ka of the amino acid serine if it is 34.5% dissociated at pH- 9.46?
Saturday, May 4, 2013 at 1:42am

analytical chemistry
A 10.00 mL aliquot of a solution of a weak acid , HA, whose pK a is 4.76 is titrated with OH - generated by electrolysis of water according to th e following scheme: 2 H 2 O + 2 e - â‡” 2 OH - + H 2 (a) [5 points] If the end point in the titration is ob served ...
Saturday, May 4, 2013 at 1:08am

analytical chemistry
Shown below is a diagram of an electrochemical cell. Write the shorthand, or schematic, notation for this cell
Saturday, May 4, 2013 at 12:34am

Practical chemistry
Preparation of 0.1m H2S04 of 500cm3 flask
Saturday, May 4, 2013 at 12:20am

Chemistry PLEASE HELP!
Manganese dioxide reacts with bromide ions to form manganese ions and bromate ions in an acidic aqueous solution. Write the balanced equation for this reaction. Select one: a. Br- + MnO2 + 3H2O Mn2+ + BrO3- + 2H3O+ b. Br- + 3MnO2 + 6H3O+ 3Mn2+ + 9H2O + BrO3- c. 6Br- + MnO2 + ...
Friday, May 3, 2013 at 8:50pm

Chemistry 104 PLEASE HELP ME!!
Calculate Eo (reduction potential) for the following balanced reaction. NiO2 + 2H2O + 2Fe(OH)2 Ni(OH)2 + 2Fe(OH)3
Friday, May 3, 2013 at 8:49pm

Chemistry
Determine the solubility of a sodium sulfate, Na2SO4, in grams per 100g of water, if 0.94 g of Na2SO4 is dissolved in 20 g of water to make a saturated solution.
Friday, May 3, 2013 at 8:22pm

Chemistry
Zinc has three major and two minor isotopes. For this problem, assume that the only isotopes of zinc are the major ones, zinc-64, zinc-66, and zinc-68. The atomic mass of zinc-64 is 63.9291 Da, that of zinc-66 is 65.9260 Da, and that of zinc-68 is 67.9248 Da. Calculate the ...
Friday, May 3, 2013 at 8:17pm

Chemistry 104
Calculate Eo (reduction potential) for the following balanced reaction. NiO2 + 2H2O + 2Fe(OH)2 Ni(OH)2 + 2Fe(OH)3
Friday, May 3, 2013 at 8:13pm

chemistry
A nitric acid solution containing 71.0% by mass of the acid has a density of 1.42g/ml how many grams of nitric acid are present in 1.0L of this solution
Friday, May 3, 2013 at 6:35pm

Chemistry Help
How many moles of ammonia are produced when 2.5 moles of nitrogen are reacted with hydrogen?
Friday, May 3, 2013 at 6:15pm

AP Chemistry Help!!
How many moles of P4O10 are produced when we react 8 moles of phosphorous with oxygen? I know the answer is: 4 mol P produces 1 mol P4O10 8 mol P produces 2 mol P4O10. Or, 1 mol P4O10 x (8 mol P / 4 mol P) = 2 mol P4O10. but, what is the balanced equation?
Friday, May 3, 2013 at 5:06pm

Chemistry II
Calculate the pH at the equivalence point in the titration of 50ml of 0.20 M methylamine (Kb=4.3*10^-4) with a 0.40 M HCL solution.
Friday, May 3, 2013 at 4:24pm

Chemistry
How many moles of P4O10 are produced when we react 8 moles of phosphorous with oxygen? I know the answer is: 4 mol P produces 1 mol P4O10 8 mol P produces 2 mol P4O10. Or, 1 mol P4O10 x (8 mol P / 4 mol P) = 2 mol P4O10. but, what is the balanced equation?
Friday, May 3, 2013 at 2:36pm

Chemistry 104
The reaction of hydrogen peroxide, sulfuric acid and lead results in the production of lead sulfate in an acidic aqueous solution. Write the balanced equation for this reaction.
Friday, May 3, 2013 at 1:40pm

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