Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
The diffusion coefficient of silver (Ag) in copper (Cu) has the following values: T (K) D (m2s-1) 923 5.42 x 10-16 1173 1.34 x 10-13 (a) Calculate the activation energy for diffusion of silver in copper. Express your answer in units of J/mol. (b) You have two specimens of ...
Friday, December 14, 2012 at 1:19am

Chemistry
The glass panels of a sky roof need to be coated in order to screen out ultraviolet radiation (10-400 nm wavelength) but without color distortion in the visible spectrum. Candidate coating materials are gallium nitride (GaN) with a band gap,Eg, of 3.2 eV, or gallium arsenide (...
Friday, December 14, 2012 at 1:16am

Chemistry
(a) Identify the feature below using correct crystallographic notation. i) (2 1 0) ii) (^-1 1/2 0) iii) (^-2 0 1) iv) (2 ^-1 0) v) [2 1 0] vi)[^-1 1/2 0] vii) [^-2 0 1] viii) [2 ^-1 0] (b) Identify the feature below using correct crystallographic notation. i) (1 ^-2 2) ii) (^-...
Friday, December 14, 2012 at 1:14am

Chemistry
Octane has a vapor pressure of 40 torr at 45.1 degrees Celsius and 400 torr at 104 degrees Celsius. What is its heat of vaporization? (Given R=8.314J/mol*K) Please explain.
Friday, December 14, 2012 at 1:06am

Chemistry
Show that a conventional x-ray generator is incapable of generating x-rays of wavelength as low as 10-11m. Do this by determining the identity of the target (in atomic number, Z) which would be needed to generate such x-rays.
Friday, December 14, 2012 at 1:04am

Chemistry
A latex balloon, wall thickness 3.091 x 10-4 m, contains helium at a concentration of 0.31 kg m-3. Under these conditions the total surface area of the balloon is 0.11 m2. The diffusion coefficient of He in latex at room temperature is 4.9 x 10-9 m2s-1. Calculate the rate of ...
Friday, December 14, 2012 at 1:04am

Chemistry
(a) Cadmium telluride (CdTe) is a semiconductor witha band gap, Eg, of 1.45 eV. Calculate the value of the absorption edge of this material. Express your answer in meters. (b) Shown below are several % absorption vs. wavelength diagrams. Identify the correct diagram for a ...
Friday, December 14, 2012 at 1:04am

Chemistry
You wish to increase the carbon content of a slab of steel by exposing it to a carburizing atmosphere at elevated temperature. The carbon concentration in the steel before carburization is 193.5 ppm and is initially uniform through the thickness of the steel. The atmosphere of...
Friday, December 14, 2012 at 1:01am

Chemistry
A solution of potassium hydroxide is in equilibrium with an undissolved solute at 45 degrees Celsius. What will happen to the mass of the potassium hydroxide if the temperature is raised to 50 degrees Celsius? (Given that heat of solution is -57.6kJ/mol)Please explain as well.
Friday, December 14, 2012 at 12:59am

Chemistry
are molar heat of vaporization and heat of vaporization the same thing?
Friday, December 14, 2012 at 12:02am

Chemistry
are molar heat of vaporization and heat of vaporization the same thing?
Thursday, December 13, 2012 at 11:59pm

chemistry
what is the molarity of the solution obtained by mixing 25.0 ml of a 3.00 M methyl alcohol solution with 225.0 ml of a 0.100 M methyl alcohol solution?
Thursday, December 13, 2012 at 11:45pm

chemistry
Wat is the volume of a 200g object that has the. Density of 1.27L?
Thursday, December 13, 2012 at 11:03pm

Chemistry
what is the magnitude and sign of the molar heat of vaporization of butane
Thursday, December 13, 2012 at 10:59pm

chemistry
Wat is the volume of a 200g object that has the. Density of 1.27L?
Thursday, December 13, 2012 at 10:49pm

chemistry 100
How do I disassociate Li2CO3 I have tried Li_2CO_3--> 2Li^+ + 3CO^2- What am I doing wrong?
Thursday, December 13, 2012 at 10:10pm

Chemistry
10.0g of sodium chloride is dissoved in 300ml of 0.75mol/L magnesium chloride solution. Find the new concentration of chloride ions f the solution.
Thursday, December 13, 2012 at 10:07pm

Chemistry
How many grams of acetic acid must be dissolved to produce 3875 ml with a Ph of 2.9?
Thursday, December 13, 2012 at 9:54pm

chemistry
What are the steps in finding the balanced equation for the complete combustion of benzene?
Thursday, December 13, 2012 at 9:16pm

Chemistry
How many electrons are there in the unipositive ion of Cs-136 (#55)? How many neutrons?
Thursday, December 13, 2012 at 8:56pm

Chemistry
How many grams of carbon dioxide can be obtained from the action of 100.0 g of sulfuric acid on 100.0 g of calcium carbonate?? I need helpim stuck!
Thursday, December 13, 2012 at 7:42pm

Chemistry
15. 120 g of sulfuric acid are added to 230.0 g of barium peroxide. Which reactant is in excess and by how much? How much barium sulfate is precipitated in this reaction???? HELP please
Thursday, December 13, 2012 at 7:26pm

chemistry
10. If the calcium oxide were obtained by the heating of calcium hydroxide, how much hydroxide would be needed to obtain the 15.0 g? 11. If the 15.0 g of calcium oxide in the above problems were allowed to react with water, what amount of calcium hydroxide would be produced? ...
Thursday, December 13, 2012 at 7:19pm

Chemistry
A compound of carbon, hydrogen, and oxygen was burned in oxygen, and 2.00 g of the compound produced 2.868 g CO2 and 1.567 g H2O. In another experiment 0.1107g of the compound was dissolved in 25.0 g of water. This solution had a freezing point of -0.0894 degrees C. What is ...
Thursday, December 13, 2012 at 5:15pm

chemistry
Which of the following best describes the Carnot cycle? A. It represents one of the least efficient cycles for converting thermal energy into work. B. It represents one of the most efficient cycles for converting thermal energy into work. C. It represents one of the most ...
Thursday, December 13, 2012 at 1:08pm

chemistry
Which of the following best describes the heat engine? A. A heat engine works through the conversion of energy in the form of heat to mechanical work. B. A heat engine works through the conversion of energy in the form of heat to chemical work. C. A heat engine works through ...
Thursday, December 13, 2012 at 1:05pm

chemistry
Internal energy is denoted by the letter U. true/false false
Thursday, December 13, 2012 at 12:29pm

chemistry
Check? Answers On bottom. Electrostatic interaction is important for which type of bond? A. ionic bond B. triple covalent bond C. single covalent bond D. double covalent bond When an atom gains or loses valence electrons and becomes charged, it is known as a(n) _____. A. ...
Thursday, December 13, 2012 at 11:05am

chemistry - exam practice help!!
For the cell shown below, which will increase the cell voltage the most? Fe2+ | Fe3+ || Cu2+ | Cu A) Halve[Cu2+] B) Double[Cu2+] C) Double[Fe2+] D) Halve[Fe2+] E) Cut Cu electrode in half ... Ecell = E0 cell + 0.059/n * log([Cu+]/[Fe2+]) Ecell is directly proportional [Cu+] to...
Thursday, December 13, 2012 at 11:00am

chemistry - exam practice help!!
Given the table below predict the numerical value of the standard cell potential for the reaction: 2 Cr(s) + 3 Cu2+(aq) 2 Cr3+(aq) + 3 Cu(s) Half Reaction E (volts) (1) Cr3+ + 3 e- Cr E= -0.74 (2) Cr3+ + e- Cr2+ E=-0.41 (3) Cr2O72- + 14 H+ + 6 e- 2 Cr3+ + 7 H2O E= 1.33 (4) Cu...
Thursday, December 13, 2012 at 10:44am

Chemistry.
How do I calculate the internuclear distances for KF, KCl, KI, and KBr?
Thursday, December 13, 2012 at 7:24am

Chemistry
Check? Answers On bottom. Electrostatic interaction is important for which type of bond? A. ionic bond B. triple covalent bond C. single covalent bond D. double covalent bond When an atom gains or loses valence electrons and becomes charged, it is known as a(n) _____. A. ...
Thursday, December 13, 2012 at 5:27am

Chemistry
Answer the following questions by referring to the Cu-Al phase diagram shown below. (a) What is the lowest temperature at which a liquid can be found in a system of any composition of Cu-Al ? (b) A common alloy composition used in airplanes is 4 at. % Cu - 96 at. % Al. For ...
Thursday, December 13, 2012 at 3:10am

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 ...
Thursday, December 13, 2012 at 3:09am

Chemistry
determine the pH of a 0.116 M Ba(OH)2 solution at 25 degrees C. i keep getting 13.06 for this answer, but the answer is 13.37 :S what i do is i take the negative log of the concentration which is 0.9355 which is pOH. i know that pH = 14 - pOH so i get pH = 13.06 where am i ...
Thursday, December 13, 2012 at 2:35am

ASAP CHEMISTRY
Determine the molar mass of the following: 0.94g of a gas that occupies 500L at 0 degrees celcius and 1.00 (STP). I keep getting 32g/mol
Thursday, December 13, 2012 at 2:19am

Chemistry
When 0.40 g of impure zinc reacted with an excess of hydrochloric acid, 127 mL of hydrogen was collected over water at 10 degress C The external pressure was 737.7 Torr. a) What volume would the dry hydrogen occupy at 1.00 atm and 298 K ? b) What amount (in moles) of H2 was ...
Thursday, December 13, 2012 at 1:56am

Chemistry
Is this done right? White phosphorous, P4, spontaneously bursts into flame in Oxygen gas. if 6.5 g of white phosphorous reacts completely with oxygen to form 11.54g of a phosphorous oxide, what is the empirical formula of this oxide? this is what i did: total = 11.4 g , P4 = 6...
Thursday, December 13, 2012 at 1:10am

chemistry - exam practice help!!
i'm not exactly sure how to do this question :/ i dont even know where to start. "Determine the equilibrium [F-] of the following solution with initial concentrations od [HF]= 1.296 M and [NaF] = 1,045 M (ka for HF is 6.6 * 10 ^ -4) options are a) 1.046 b) 0.251 c) 2....
Wednesday, December 12, 2012 at 10:57pm

Chemistry
How to figure out half-lives Half-live of Indium-116 is 14 seconds. How long will it take for 32 grams of this istotopw to decay to 1.0 grams. I know the answer is 70seconds but do not know how to get it!
Wednesday, December 12, 2012 at 10:35pm

chemistry
A sample of gas has a mass of 0.585g . Its volume is 110mL at a temperature of 95^\circ C and a pressure of 745mm\;Hg .
Wednesday, December 12, 2012 at 10:15pm

Chemistry
Nitrogen and hydrogen gases react to form ammonis gas as follows: N2(g)+3H2(g)-->2NH3(g) At a certain temperature and pressure, 1.2L of N2 reacts with 3.6L of H2. If all the N2 and H2 are consumed, what volume of NH3 at the same temperature and pressure will be produced? I...
Wednesday, December 12, 2012 at 9:42pm

chemistry
How many grams of water can be formed from 10 grams of oxygen?
Wednesday, December 12, 2012 at 8:32pm

chemistry
What is the molarity of 5g of O2 in 250 mL? Show work, please.
Wednesday, December 12, 2012 at 7:44pm

Chemistry
4 moles of Zinc reacted with an excess of hydrochloric acid. Calculate the grams, moles,and liters at stp of gas made.Please help!!!!!!!!
Wednesday, December 12, 2012 at 6:33pm

chemistry
The vapor pressure of pure water at 70°C is 231 mm Hg. What is the vapor pressure depression of a solution of 115 g of the antifreeze ethylene glycol, C2H6O2, a nonvolatile compound, in 205 g of water? Use molar masses with at least as many significant figures as the data ...
Wednesday, December 12, 2012 at 6:20pm

chemistry
Which of the following is the correct angle between the atoms in a seesaw molecule? A. <90o, <120o B. <180o C. 270o D. 360o A.
Wednesday, December 12, 2012 at 4:22pm

chemistry
VSEPR theory is a model that is used to represent the shapes or molecular geometries of individual molecules. True False false
Wednesday, December 12, 2012 at 4:19pm

chemistry
Which of the following is the correct angle between the atoms in an octahedral molecule? A. 90o B. 120o C. 180o D. 270o B.
Wednesday, December 12, 2012 at 3:48pm

chemistry
How many resonance structures does N3- have? A. 2 B. 3 C. 4 D. No resonance C. 4
Wednesday, December 12, 2012 at 3:30pm

chemistry
Which of the following is the correct angle between the atoms in a linear molecule? A. 90o B. 120o C. 180o D. 270o i think D
Wednesday, December 12, 2012 at 3:27pm

chemistry
H2 + I2 -> 2Hl 1.2 mol of hydrogen gas reacts with 1.0 mol of iodine vapour, after 5 minutes 0.6 mol of iodine remained. A) calculate the number of moles of hydrogen that have not reacted after 5 minutes. B) calculate the number of moles of hydrogen iodide that have been ...
Wednesday, December 12, 2012 at 2:37pm

chemistry
how many molecules are present in 1.2 mol of glucose, C6H12O6?
Wednesday, December 12, 2012 at 1:01pm

Chemistry
If 355 g Al(NO3)3 reacts with an excess of K2CrO4, how many moles of KNO3 would be produced?
Wednesday, December 12, 2012 at 1:56am

chemistry
3.50 mol Al(NO3)3 reacts with 5.00 mols K2CrO4, the total number of moles of Al2(CrO4)3 and KNO3 would be? Here is the equation if it's needed. 2 Al(NO3)3(aq) + 3 K2CrO4(aq) → Al2(CrO4)3(s) + 6 KNO3(aq)
Wednesday, December 12, 2012 at 1:51am

Chemistry
What is the molarity of a solution of Mg(OH)2 if the solution contains 1.35 g in exactly 100 mL of solution??? A 15.0 mL solution of H2SO3 is neutralized by 12.0 mL of a standradized 1.00M NaOH solution. What is the concentration of the H2SO3 solution?????? What volume of a 1....
Wednesday, December 12, 2012 at 12:24am

Chemistry
what is dispersion,dipole,hydrogen bonding for NaF,N3H,NaBr.
Wednesday, December 12, 2012 at 12:10am

Chemistry..
Dispersion force,dipole-dipole,hydrogen bonding...please explain each.
Wednesday, December 12, 2012 at 12:09am

Chemistry - solubility, not "Methode Champenoise"
Is CO2 soluble in ethanol? I know that CO2 is nonpolar, so that means it's soluble in nonpolar solvents, but CO2 is soluble in H2O. H2O is polar. Also, if CO2 were obeying Henry's Law, would it be soluble in ethanol at a high pressure?
Tuesday, December 11, 2012 at 11:47pm

chemistry
a gas occupies a volume of 5.00L at 27 degreesC and 742 mmHg. if the volume is held constant and the temperature is increased by 2 degreesC, what is the final pressure of the gas?
Tuesday, December 11, 2012 at 11:40pm

Chemistry
How many atoms of O are in 4 moles of (NH4)3PO4 - 6H2O? The answer is 2.41x10^25 I have no clue how to arrive at this answer.
Tuesday, December 11, 2012 at 11:34pm

chemistry
A 1.252g sample containing iron dissolved and converted to Fe followed by ADDITION OF 25ML OF 0..01m K2CR2 07. THE EXCESS K2CR207 REQUIRED 6.85ML OF 0.015m SN2+. Find the percentage fe3 04 fw 213g/mol in the sample. Who helps me
Tuesday, December 11, 2012 at 11:27pm

Chemistry
If the half-life of uranium-235 is 7.04 (times) 10 (to the eight power) 8 y and 12.5 g of uranium-235 remain after 2.82 (times) 10 (to the ninth power) y, how much of the radioactive isotope was in the original sample?
Tuesday, December 11, 2012 at 11:26pm

Chemistry
Carbon-14 has a half-life of 5730 y. How much of a 144 g sample of a carbon-14 will remain after 1.719 (times) 10 4y?
Tuesday, December 11, 2012 at 11:22pm

Chemistry
Potassium-42 has a half life of 12.4 hours. How much of an 848 g sample of potassium-42 will be left after 62.0 hours? Please help me!!
Tuesday, December 11, 2012 at 11:19pm

Chemistry
Chromium-48 has a short half-life of 21.6 h. How long will it take 360.00 g of chromium-48 to decay to 11.25g. Please help me
Tuesday, December 11, 2012 at 11:17pm

Chemistry
The half-life of hafnium-156 is 0.025 s. how long will it take a 560 g sample to decay to one-fourth it's original mass?
Tuesday, December 11, 2012 at 11:15pm

Chemistry
If the half life of Iodine-131 is 8.10 days, how long will it take for 120.0 g to decay to 7.50g?
Tuesday, December 11, 2012 at 11:13pm

Chemistry
Thallium-208 has a half life of 3.053 min. How long will it take for 120.0 g to decay to 7.50 g?
Tuesday, December 11, 2012 at 11:12pm

chemistry
In the "Methode Champenoise," grape juice is fermented in a wine bottle to produce sparkling wine. The reaction is given below. C6H12O6(aq)--> 2 C2H5OH(aq) + 2 CO2(g) Fermentation of 746 mL grape juice (density = 1.0 g/cm3) is allowed to take place in a bottle ...
Tuesday, December 11, 2012 at 11:11pm

Chemistry
If 100.0 g of carbon-14 decays until only 25.0 g of carbon is left after 11,460 y, what is the half-life of carbon-14?
Tuesday, December 11, 2012 at 11:10pm

Chemistry
A 208 g sample of sodium-24 decays to 13.0 g of sodium-24 within 60.0 h. What is the half-life of this radioactive isotope?
Tuesday, December 11, 2012 at 11:08pm

Chemistry
All isotopes of technetium are radioactive, but they have widely varying half-lives. If an 800.0 g sample of technetium-99 decays to 100.0 g of technetium-99 in 639,000 y, what is its half life
Tuesday, December 11, 2012 at 11:06pm

Chemistry
What is the density of 3.40 liters of hci
Tuesday, December 11, 2012 at 10:59pm

Chemistry
What is the half-life of a 100.0 g sample of nitrogen-16 that decays to 12.5 g of nitrogen-16 in 21.6 s? Please help me!!
Tuesday, December 11, 2012 at 10:57pm

chemistry 122
81) According to the following thermochemical equation, what mass of HF (in g) must react in order to produce 345 kJ of energy? Assume excess SiO2. SiO2(s) + 4 HF(g) �� SiF4(g) + 2 H2O(l) DH°rxn = -184 kJ 81) A) 173 g B) 37.5 g C) 150. g D) 107 g E) 42.7 g
Tuesday, December 11, 2012 at 9:48pm

chemistry
SOCl2 + C4H6CaO4 ¨
Tuesday, December 11, 2012 at 9:41pm

chemistry lab
When determining the molar mass of a volatile liquid by heating the liquid and then using the condensed, volatile vapor's mass, why do volatile liquids with lower boiling points give better results? Also, what effect would the formation of dimers have on the experimental ...
Tuesday, December 11, 2012 at 8:30pm

Chemistry
what is dispersion,dipole,hydrogen bonding of HBr NH3 NaF
Tuesday, December 11, 2012 at 8:08pm

Chemistry..
How many O atoms are there in a mole O2? My answer: 6.02*10^23
Tuesday, December 11, 2012 at 8:08pm

Chemistry
Compute the volume of helium at 1.0 atm and 298 K that will be collected if 2.5 g of 222Rn is stored in a container able to expand to maintain a constant pressure for 15 days. Assume that 222Rn decays to 218Po with a half-life of 3.824 days.
Tuesday, December 11, 2012 at 7:52pm

Chemistry
N2O5 + H2O ---> 2HNO3 The reaction is first order in each reactant. Write the rate law for the reaction my guess rate= k[N2O5]^1[H2O]^1
Tuesday, December 11, 2012 at 7:10pm

chemistry
write the reaction of propanal reacting with: CH3CH2NH2 and CH3MgClthen H2O/H+
Tuesday, December 11, 2012 at 6:30pm

chemistry
hey guys need some help here!!! if 0.250mol of CO and 0.250mol of H2O were combined in a 125mL flask and the reaction allowed to reach equilibrium . Kc= 1.56. write the equ expression and calculate each substance Co(g) +H2O(g) .... Co2(g) +H2(g)
Tuesday, December 11, 2012 at 6:18pm

chemistry
The theoretical yield of a reaction is 78.5 grams of product and the actual yield is 66.3 grams. What is the percent yield?
Tuesday, December 11, 2012 at 5:42pm

Chemistry
The pressure of a 27o mL sample of gas is 102 kPa. What would be the pressure if the volume were increased to 378 mL?
Tuesday, December 11, 2012 at 5:28pm

chemistry
* A 50 gram sample of an unknown metal warms from 18 to 58 after absorbing 800 joules of energy. what is the specific heat of the metal? *copper has a specific heat of 0.387 j/g degree celsius. what is the mass of a piece of copper that undergoes a 21.0 C temperature change ...
Tuesday, December 11, 2012 at 5:23pm

chemistry
2NaClO2---> 2NaCl + 3O2 if 3.85 grams of NaClO3 react, how many moles of O2 are created?
Tuesday, December 11, 2012 at 5:22pm

Chemistry
Is this reaction exothermic or endothermic? Fe(NO3)3+ NaSCN
Tuesday, December 11, 2012 at 5:03pm

Chemistry
The ΔHof of gaseous dimethyl ether (CH3OCH3) is –185.4 kJ/mol; the vapour pressure is 1.00 atm at –23.7oC and 0.526 atm at –37.8oC. a) Calculate ΔHovap of dimethyl ether. b) Calculate ΔHof of liquid dimethyl ether Any idead how to calculate for ...
Tuesday, December 11, 2012 at 3:58pm

chemistry
If the 12.5ml of NaOH solution is required to react completely with 0.300g of KHP (Potassium Hydrogen Phthalate, 204.2g/mol). What is the molarity of NaOH?
Tuesday, December 11, 2012 at 3:57pm

Chemistry
Consider a 0.71 M solution of each of the following salt dissolved in distilled water. Will the solution by basic, neutral, or acidic? KI= NH4NO2= (CH3CH2)3NHNO2= (CH3CH2)2NH2ClO4=
Tuesday, December 11, 2012 at 3:33pm

Chemistry
a 0.451 L solution of 1.71 ascorbic acid (ka1=7.9E-5, ka2=1.6E-12) is titrated with 1.35 M NaOH. What is pH when 0.9540 L of NaOH is added?
Tuesday, December 11, 2012 at 3:30pm

chemistry
The concentration of ammonium phosphate, (NH4)3PO4, is 1.60 M. What is the concentration of ammonium ions in solution?
Tuesday, December 11, 2012 at 1:22pm

Chemistry
Health regulations stipulate that the amount of arsenate in drinking water be no grater than 10 parts per billion (ppb) arsenic. If the arsenic present is arsenate, AsO4^-3, what mass of sodium arsenate would be present in a 1.00 L sample of drinking water that just meets the ...
Tuesday, December 11, 2012 at 12:12pm

Chemistry
In the "Methode Champenoise," grape juice is fermented in a wine bottle to produce sparkling wine. The reaction is given below. C6H12O6(aq)--> 2 C2H5OH(aq) + 2 CO2(g) Fermentation of 746 mL grape juice (density = 1.0 g/cm3) is allowed to take place in a bottle ...
Tuesday, December 11, 2012 at 9:27am

Science- Chemistry
Determine the type of bonding in each substance. a. Zinc, Zn (s) b. Propane, C3H8 (l) c. Calcium Carbonate, CaCO3 (s)
Tuesday, December 11, 2012 at 9:16am

Chemistry HELP
A 0.75–L bottle is cleaned, dried, and closed in a room where the air is 22oC and 44% relative humidity (that is, the water vapour in the air is 0.44 of the equilibrium vapour pressure at 22oC). The bottle is brought outside and stored at 0.0oC. just this question cause i...
Tuesday, December 11, 2012 at 7:53am

Chemistry
A 0.75 L bottle is cleaned, dried, and closed in a room where the air is 22°C and 47% relative humidity (that is, the water vapor in the air is 0.47 of the equilibrium vapor pressure at 22°C). The bottle is brought outside and stored at 0.0°C. My question is what ...
Tuesday, December 11, 2012 at 7:29am

Chemistry
The equation for photon energy, , is where = 6.626×10−34 (Planck's constant) and = 3.00×108 (the speed of light). What is the wavelength, , of a photon that has an energy of = 3.99×10−19 ? How do go about solving this? I multipled the constant...
Tuesday, December 11, 2012 at 4:04am

Chemistry
The fictitious compound, pandemonium carbonate Pn(CO3)2 hase a Ksp=3.091x10^-9M3 in water at room temperature. Calculate the solubility of Pn(CO3)2 in an aqueous solution of 1.11 M pandemonium sulfate Pn(SO4)2 (aq) . Express your answer in units of molarity.
Tuesday, December 11, 2012 at 3:44am

Chemistry
The solubility of the fictitious compound, administratium fluoride ( AdF3 ) in water is 3.091x10^-4M . Calculate the value of the solubility product Ksp .
Tuesday, December 11, 2012 at 3:37am

Chemistry
(a) The phase diagram of the binary system, neodymium-scandium ( Nd-Sc ) is given below. There are two polymorphs in the solid state: alpha which is hexagonal close packed (HCP) and beta which is body-centered cubic (BCC). Identify all phases present at points 1, 2, and 3. ...
Tuesday, December 11, 2012 at 3:35am

Chemistry
Question One Lead chloride dissolves in water according to PbCl2(s)<-> Pb^2+ + 2Cl^- (aq) The solubility in pure water has been measured to be 4.44g . L^-1 . Calculate the solubility product of lead chloride in pure water. Your answer should be in units of molarity ...
Tuesday, December 11, 2012 at 3:30am

Chemistry
Question One The fictitious compound, pandemonium fluoride ( PnF2 ) has a Ksp value in water of 3.091x10^-9 M^3 at room temperature. Calculate the solubility of PnF2 in water. Express your answer in units of molarity. Question Two How would you expect the solubility of ...
Tuesday, December 11, 2012 at 3:24am

Chemistry
Question One: Comment on the solubility of hydrogen ( H2 ) in liquid ammonia ( NH3 ). State whether you expect hydrogen to be highly soluble or almost insoluble, and explain why. i)Highly soluble due to hydrogen bonding. ii)Highly soluble due to compatible nature of bonds. iii...
Tuesday, December 11, 2012 at 3:21am

Chemistry
Here is the phase diagram of water with attention given to phases at high pressure. Name all phases present at the markers 1, 2 and 3. Phases present at 1: Liquid I II III IV V VI VII VIII IX Phases present at 2: Liquid I II III IV V VI VII VIII IX Phases present at 3: Liquid ...
Tuesday, December 11, 2012 at 3:17am

chemistry
At a certain temperature, the Equilibrium constant, Kc, for this reaction is 53.3. At this temperature, 0.500 mol of H2 and 0.500 mol of I2 were placed in a 1.00-L container to react. What concentration of HI is present at Equilibrium? equation: H2 + I2 = 2HI
Tuesday, December 11, 2012 at 1:40am

Chemistry PLEASE HELP!!!
'A buffer is prepared by mixing a 100.omL of a 0.100 M NH3 solution with a 0.200M solution of NH4CL solution and making the total volume up to 1.000L of water. What is the volume of NH4Cl solution required to achieve a buffer at ph=9.5? Ka of NH4=5.6x10^-10. The textbook ...
Tuesday, December 11, 2012 at 12:14am

Chemistry
Hi, i'm really desperate! could anyone please help me with this question, I'm stumped. 'A buffer is prepared by mixing a 100.omL of a 0.100 M NH3 solution with a 0.200M solution of NH4CL solution and making the total volume up to 1.000L of water. What is the volume...
Tuesday, December 11, 2012 at 12:02am

Chemistry - Molarity
Potassium hydrogen phthalate is a monoprotic acid. Dihydrogen phthalate (H2C8H4O4) is a diprotic acid. An analyte sample contains 0.127 M KHP and 0.0678 M H2C8H4O4. What volume of a 0.205 M NaOH solution is required to neutralize 25.0 mL of the analyte solution? Molar masses: ...
Monday, December 10, 2012 at 10:56pm

Chemistry
please explain how % error and % yield would have effected the mass/moles of a substance in a reaction in a lab. In this case mass/moles of NaCl. NaHCO3+ HCl--> NaCl + CO2 + H2O
Monday, December 10, 2012 at 10:51pm

Chemistry 3A
C2H2(g)+ 5/2o2(g)-> 2Co2(g)+ H2o(g)+ 1255.8KJ how many grams of C2H2 are reacted when 310 KJ of heat are released? I left the oxygen (O) lowercase in the equation so it does not get mixed up with zero.
Monday, December 10, 2012 at 10:07pm

Chemistry 3A
CS2 + O2 -> CO2 + SO2 and 10.0 grams of each reactant, calculate the number of moles of SO2 that can be produced in this reaction
Monday, December 10, 2012 at 9:56pm

Chemistry 3A
compute the molarity of a solution consisting of 2.0 moles of calcium chloride in 500mL of solution.
Monday, December 10, 2012 at 9:42pm

Chemistry 3A
How many grams of KCl would you need to weigh out to prepare 0.25L of a 2.00 M KCl solution?
Monday, December 10, 2012 at 9:42pm

Chemistry 3A
calculate the mass of solid NaCl that must be added to 1.50L of a 0.100M AgNO3 solution to precipitate all the Ag+ ions in the form of AgCl. calculate the mass of AgCl formed.
Monday, December 10, 2012 at 9:39pm

chemistry
Assume that a particular reaction evolves 241 of heat and that 25 of work is gained by the system. What are the values of delta E and delta H for the system?
Monday, December 10, 2012 at 9:35pm

Chemistry
I have to sort compounds into groups, separating them by if they are acidic, Ionic, or Covalent. Heres the list: Calcium Carbonate Sodium Hypochlorite Sodium Chloride Sodium Hydrogen Carbonate Acetic Acid Ammonium Hydroxide Silicon dioxide Magnesium Sulfate Carbon Dioxide ...
Monday, December 10, 2012 at 9:21pm

chemistry urgent urgent
Analyze the properties of a sodium atom and a sodium ion. What are the differences in mass, stability, and reactivity that are caused due to the differences between the sodium atom and sodium ion?
Monday, December 10, 2012 at 9:00pm

chemistry
Acetyl chloride is a colorless, fuming liquid used primarily in the chemical industry. a)How is acetyl chloride produced? If 915 gallons is produced and shipped, will DOT require the carrier to display the FLAMMABLE placard? Explain your answer. b)When there is a bulk spill of...
Monday, December 10, 2012 at 8:31pm

Chemistry
How much heat (in kilojoules) is evolved or absorbed in the reaction of 3.35 of with enough carbon monoxide to produce iron metal?
Monday, December 10, 2012 at 8:17pm

chemistry
What volume in mL of 0.0985 M sodium hydroxide solution is required to reach the equivalence point in the complete titration of a 15 mL sample of 0.124 M phosphoric acid?
Monday, December 10, 2012 at 8:06pm

chemistry
how many moles of NaCl are in a box of salt containing 425g NaCl (g/mol)
Monday, December 10, 2012 at 7:47pm

chemistry
A scuba diver's tank contains 0.29kg of O2 compressed into a volume of 2.3L. Calculate the gas pressure at 8 degrees celcius.
Monday, December 10, 2012 at 7:15pm

Chemistry
A reverse osmosis unit is used to obtain drinkable water from a source that contains 0.530 g NaCl per liter. What is the minimum pressure (in torr) that must be applied across the semipermeable membrane to obtain water? Assume room temperature or about 298 K. (Don′t ...
Monday, December 10, 2012 at 7:09pm

Chemistry 3A
what is the maximum number of electrons that may occupy the second electron energy level?
Monday, December 10, 2012 at 6:59pm

Chemistry
A mixture of gases contains 2.00 mol of O2, 3.00 mol of N2, and 5.00 mol of He. The total pressure of the mixture is 850 torr. What is the partial pressure of each gas?
Monday, December 10, 2012 at 6:33pm

Chemistry
If the osmotic pressure of urea (CH4N20) in water is measured at 0.0259 atm at 25 degress C what is the molartiy of the urea solution?
Monday, December 10, 2012 at 6:11pm

Chemistry
if a student finds the molecular weight of an unknown liquid to be 115 g/mole and the molecular formula of the liquid is CHCl3, what is the percent error in the student's molecular weight?
Monday, December 10, 2012 at 6:06pm

Chemistry
How many moles of a gas fill a flask with a volume of 141 mL at 101 degrees Celsius and a pressure of 761 torr?
Monday, December 10, 2012 at 6:01pm

chemistry
determining the concentration of a strong acid HCl when your given that the volume is 10ml and the mass of NaOH is 0.10 and the volume is 13.45
Monday, December 10, 2012 at 5:54pm

chemistry
Please help. My teacher never went over crystal lattices and the book doesn't cover it either :( Copper crystallizes in a face-centered cubic lattice. If the edge of the unit cell is 351pm, what is the radius of the copper atom?
Monday, December 10, 2012 at 4:35pm

Chemistry 3A
what is the maximum number of electrons that may occupy the second electron energy level?
Monday, December 10, 2012 at 2:51pm

Chemistry 3A
calculate the empirical formula for an unknown compound from the following information: C= 39.2%, H= 8.73% and O= 52.1%
Monday, December 10, 2012 at 2:39pm

Chemistry 3A
how do i find the number of moles of oxygen atoms in: Al(OH)3
Monday, December 10, 2012 at 2:10pm

Chemistry 3A
how do we write a nuclear symbol?
Monday, December 10, 2012 at 1:32pm

chemistry
the oxidation number of Mn in MnO4- is +4 (true or false)
Monday, December 10, 2012 at 10:39am

chemistry
mixed about the 5grams of benzois acid and sugar. divide the mixture into two equal portions . to thheh first portion add 20ml of water. shake vigorously and filter. examine the residue and compare with the original sample. heat the filter to dryness and identify the residue. ...
Monday, December 10, 2012 at 10:33am

chemistry
a 2.55g sample of an unknown has a volume of 3.73 cm. what is the density of the unknown
Monday, December 10, 2012 at 10:24am

chemistry
#1 A pipet delivers 10.5, 10.3, 10.9 and 10.7 ml (a) find the mean volume and deviation from the mean for each and calculate the average deviation from the mean (b) calculate the relative deviation (in %) for this set of data. Relative deviation (%) = (average deviation from ...
Monday, December 10, 2012 at 10:05am

chemistry
a 2.55g sample of an unknown has a volume of 3.73 cm. what is the density of the unknown
Monday, December 10, 2012 at 10:01am

Chemistry
The fictitious compound, arrhenium fluoride (AhF), reacts with itself to form a dimer with the formula Ah2F2. The reaction is second order in AhF. The value of the rate constant is 8.591x10-3 M-1s-1. What is the initial rate of reaction in a reactor filled with AhF to a ...
Monday, December 10, 2012 at 1:31am

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