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August 21, 2014

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

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Chemistry
I need to balance the equation of the reactants NaHCO3->CuCl2 please help me.
Sunday, March 23, 2014 at 9:32am

Chemistry
What is the total heat evolved when a saturated solution of boric acid (H3BO3) in water is cooled from 100C to 20C? Note the specific heat capacity of the saturated solution is approximately that of water in that temperature range (4.20 J/g.K) and the specific heat capacity of...
Sunday, March 23, 2014 at 5:45am

Chemistry
When 24g of Magnesium reacts with oxygen gas the only product is magnesium oxide. If 40g magnesuim is produced how much oxygen was consumed?
Saturday, March 22, 2014 at 9:33pm

Chemistry - check answers
1) Which element has the largest first ionization energy? A) Rb, B) Fr, C) K, D) Na, E) Mg Answer: E 2) Which has the highest electronegativity? A) Na, B) Cs, C) Si, D) Te, E) Cl Answer: E 3) In which of the following are the bonds arranged in order of increasing polarity? A) ...
Saturday, March 22, 2014 at 8:22pm

Chemistry
The decomposition of hydrogen iodide on a gold surface at 150 oC HI(g) ½ H2(g) + ½ I2(g) is zero order in HI. In one experiment, when the initial concentration of HI was 0.206 M, the concentration of HI dropped to 3.71E-2 M after 898 seconds had passed. Based on ...
Saturday, March 22, 2014 at 7:45pm

Chemistry
The decomposition of hydrogen iodide on a gold surface at 150 oC HI(g) ½ H2(g) + ½ I2(g) is zero order in HI with a rate constant of 1.20E-4 Ms-1. If the initial concentration of HI is 0.575 M, the concentration of HI will be 0.116 M after how many seconds have ...
Saturday, March 22, 2014 at 7:03pm

Chemistry
The decomposition of hydrogen iodide on a gold surface at 150 oC HI(g) ½ H2(g) + ½ I2(g) is zero order in HI with a rate constant of 1.20E-4 Ms-1. If the initial concentration of HI is 0.575 M, the concentration of HI will be 0.116 M after seconds have passed.
Saturday, March 22, 2014 at 7:02pm

Chemistry
an extremely soluable salt is added to water, and all of it dissolves. is it at equilibrium? explin.
Saturday, March 22, 2014 at 6:47pm

chemistry
calculate the freezing point of an aqueous solution of 15.5 grams of glucose dissolved in 150 grams of water
Saturday, March 22, 2014 at 5:32pm

chemistry
Calculate the molar conc. Of ethanoate acid needed to prepare ethonoic buffer of ph 6.8 using 0.5 molar solution of sodium ethanoic.pka of acid 0..127
Saturday, March 22, 2014 at 1:16pm

Chemistry
Complete and balance the equation for this reaction in basic solution? Redox reaction Cr is oxidized to CrO42– and Fe3 is reduced to Fe2...? For a particular redox reaction Cr is oxidized to CrO42– and Fe3 is reduced to Fe2 . Complete and balance the equation for ...
Saturday, March 22, 2014 at 9:45am

Chemistry
1.350g of insoluble carbonate, MCO3 was dissolved in 250cm^3 of a 0.203 mol/dm^3 HCL solution. The resulting solution was boiled off to remove all carbon dioxide produced. 25.0 cm^3 of the solution required 24.10cm^3 of 0.100 mol/dm^3 sodium hydroxide solution. Determine the ...
Saturday, March 22, 2014 at 9:39am

Urgent Chemistry
The Heisenberg Uncertainty Principle: A student is examining a bacterium under the microscope. The E. coli bacterial cell has a mass of mm = 0.100fg\rm fg (where a femtogram, fg\rm fg, is 10−15g\rm 10^{-15}\; g) and is swimming at a velocity of vv = 7.00ìm/s\mu m/...
Saturday, March 22, 2014 at 6:42am

chemistry
Given these standard reduction potentials at 25oC: Cr3+ + e- -> Cr2+ (E1^o = -0.407V) Cr2+ + 2e- -> Cr(s) (E2^o = -0.913V) Determine the standard reduction potential at 25oC for the half-reaction equation: Cr3+ + 3e- -> Cr(s) This seems like a really simple problem (...
Friday, March 21, 2014 at 11:46pm

Chemistry
carbon dioxide dissolves in water to form carbonic acid. Estimate the thermodynamic equilibrium constanst (K) for this reaction (delta Gf values: H2CO3= - 616.1, H2O= - 237.1, CO2= - 394.4) . Carbonic acid then ionizes in water (Ka1= 4.5 x 10^-7). Ignoring Ka2, estimate (K) ...
Friday, March 21, 2014 at 4:47pm

Chemistry-Repost for DrBob222
500 ml of a buffer solution with ph=2.10 must be prepared using .4 M HNO2 and solid KNO2. The ka value of HNO2 is 4e-3. a.) What mass of KNO2 should be added to 3 L of the HNO2 to make the buffer? b.) What is the buffer's pH after 150 ml of .5 M HNO3 is added? Your answer ...
Friday, March 21, 2014 at 2:34pm

Chemistry
Given that 20 ml of a weak acid (HA) was titrated with NaOH and the titration curve of pH vs titrant volume in ml is given, find the initial concentration of the acid? The problem gives the full titration curve starting at pH=2.2 at 0 ml added and with the equivalance pt at pH...
Friday, March 21, 2014 at 2:11pm

Chemistry-Repost for DrBob222
A sample of C60O3 decomposes with an activation energy of 50 kg/mol, an Arrehnius pre-factor of 2e10 s-1 and a k value of .04 s-1. How long does it take for a 25 mg sample at 25 degrees C to produce 10 mg. Your response was is that C60O<suh>3 or what? And I thought ...
Friday, March 21, 2014 at 2:06pm

Chemistry
What is the pH of a solution prepared by mixing 24.6 g sodium acetate and 50 mL of 2.5 M acetic acid in a 500 mL flask and filling to volume
Friday, March 21, 2014 at 12:58pm

Chemistry-Repost for DrBob222
The reaction OH- + NH4+ = H20 + NH3 is kinetically first order in both reactants' concentrations. The rate constant is 2e10 1/M s. If 50 ml of .01 M NaOH is mixed with 50 ml of .01 M NH4CL, find the time required for the OH- concentration to reach 1e-4 M. Your answer: It ...
Friday, March 21, 2014 at 10:39am

Chemistry-Repost for DrBob222
My question was: A saturated solution of MgF2 at 23 degrees C was prepared by dissolving solid MgF2 in 1 L water. The Ksp of MgF2 is 1.5e-5. a.)Calculate the mass of MgF2 dissolved. b.) When .1 mols of solid KF was dissolved in the MgF2 solution, precipitation was observed. ...
Friday, March 21, 2014 at 10:34am

Chemistry
The Heisenberg Uncertainty Principle: A student is examining a bacterium under the microscope. The E. coli bacterial cell has a mass of mm = 0.100fg\rm fg (where a femtogram, fg\rm fg, is 10−15g\rm 10^{-15}\; g) and is swimming at a velocity of vv = 7.00ìm/s\mu m/...
Friday, March 21, 2014 at 6:31am

Chemistry
The Heisenberg Uncertainty Principle: A student is examining a bacterium under the microscope. The E. coli bacterial cell has a mass of mm = 0.100fg\rm fg (where a femtogram, fg\rm fg, is 10−15g\rm 10^{-15}\; g) and is swimming at a velocity of vv = 7.00ìm/s\mu m/...
Friday, March 21, 2014 at 6:31am

Chemistry
The following reaction has the following standard thermodynamic parameters: Reaction: C(g) + D(g)----> E(g) Delta H rxn=-26.1kJ/mol and Delta S rxn=-69.8J/(mol*K). Calculate the temperature at which the reaction becomes nonspontaneous.
Friday, March 21, 2014 at 1:32am

chemistry
The pressure in an automobile tire is 1.85 atm at 27.0°C. What will be the pressure if the temperature increases to 38.0°C?
Thursday, March 20, 2014 at 10:23pm

Chemistry
HClO(aq) + H2O (l) <> H3O+ (aq) + ClO-(aq) Calculate the value of ΔGrxn at 25 °C for hypochlorous acid when [ClO-]=[H3O+]=5.69x10^-5 M [HClO] = 1.340 M Previously calculated a ΔGºrxn of 42.20 kJ/mol Q = [5.69x10^-5] / [1.340] = .00004245 M equation ...
Thursday, March 20, 2014 at 9:05pm

Chemistry HELP PLEASE!!
write the oxidation and reduction half-reactions that occur at the anode and cathode, respectively, when MgCl2 liquid is electrolyzed using inert electrodes. HELP PLEASE!!!
Thursday, March 20, 2014 at 8:15pm

Chemistry
The mechanism for NH2NO2=N2O+H2O occurs in three steps: step 1: NH2NO2=NHNO2- + H+ (forward and reverse reactions are fast) step 2: NHNO2-=N2O+OH- (slow) step 3: H+ + OH-=H20 (very fast) What is the rate law for d[N2O]/dt as determined by the mechanism?
Thursday, March 20, 2014 at 6:33pm

Chemistry
500 ml of a buffer solution with ph=2.10 must be prepared using .4 M HNO2 and solid KNO2. The ka value of HNO2 is 4e-3. a.) What mass of KNO2 should be added to 3 L of the HNO2 to make the buffer? b.) What is the buffer's pH after 150 ml of .5 M HNO3 is added?
Thursday, March 20, 2014 at 6:06pm

Chemistry
A sample of C60O3 decomposes with an activation energy of 50 kg/mol, an Arrehnius pre-factor of 2e10 s-1 and a k value of .04 s-1. How long does it take for a 25 mg sample at 25 degrees C to produce 10 mg.
Thursday, March 20, 2014 at 6:03pm

chemistry
if you had 0.028 moles of copper sulfide, how many grams would you have?
Thursday, March 20, 2014 at 5:03pm

CHEMISTRY
I need to find the rate law of a reaction but ive only done so when factors cancel out, this one has all different numbers and im not quite sure what to do with it. It has time taken every second (which im assuming are the different trials) and different concentrations of OH...
Thursday, March 20, 2014 at 3:55pm

CHEMISTRY
An electron undergoes a transition from an n=3 to an n=1 stationary state and red light is released. Which of the following forms of electromagnetic radiation could be released for an n=2 to n=1 electron transition within the same atom? -blue visible light -yellow visible ...
Thursday, March 20, 2014 at 3:25pm

chemistry
Cabbage Juice Titration Lab connexus
Thursday, March 20, 2014 at 3:20pm

CHEMISTRY
CaCO3(s)+2HCl(aq)>CaCl2(aq)+H2O(l)+CO​2(g) how many grams of calcium chloride will be produced when 30 g of calcium carbonate are combined with 13 g of hydrochloric acid? Which reactant is in excess and how many grams of this reactant will remain after the reaction is...
Thursday, March 20, 2014 at 2:37pm

General Chemistry
A piston has an external pressure of 7.00 atm. How much work has been done in joules if the cylinder goes from a volume of 0.130 liters to 0.650 liters. Express your answer with the appropriate units.
Thursday, March 20, 2014 at 12:17pm

logic-math
Calculate the truth value (f or V) a. Is it true that if (the Papaya is a fruit from the Caricaseas or the Pitahaya is the fruit of a plat from the Cactaseas) then (el Cohombro is a fruit of a plant from the family of the Cucurbitaceas or the Nisper is a fruit of a tree from ...
Thursday, March 20, 2014 at 12:01pm

chemistry
Calculate the percent yield for an experiment in which 46.9 g of SO3 was produced upon the reaction of 51.2 g of SO2 with 25.0 g O2
Thursday, March 20, 2014 at 9:53am

Chemistry
If your Copper(II)sulfate solution contains 0.8 grams of Cu and you recovered 0.76 grams of it, what would be the percent yield?
Thursday, March 20, 2014 at 9:38am

Chemistry
The Ksp of tin(II) hydroxide, Sn(OH)2, is 5.45 × 10-27. Calculate the solubility of this compound in g/L.
Thursday, March 20, 2014 at 1:09am

chemistry
A gas mixture contains 75.2% nitrogen and 24.8% krypton by mass. What is the partial pressure of krypton in the mixture if the total pressure is 853mmHg ?
Thursday, March 20, 2014 at 12:20am

Chemistry
A heliox deep-sea diving mixture contains 2.0 g of oxygen to every 98.0 g of helium.What is the partial pressure of oxygen when this mixture is delivered at a total pressure of 8.9atm ?
Thursday, March 20, 2014 at 12:16am

Chemistry
In a heating and cooling curve, I understand that the flat part means that the bonds are either forming or breaking, depending on if the input of energy is increasing or decreasing, but what is happening to the bonds in the slanted parts? Thanks!
Wednesday, March 19, 2014 at 11:29pm

chemistry
How many moles of sodium chloride can be produced if 29g of Magnesium Chloride are reacted in the reaction 2NaNO3 + MgCl> 2NaCl+Mg (NO3)2?
Wednesday, March 19, 2014 at 10:46pm

Chemistry
The energies, E, for the first few states of an unknown element are shown here in arbitrary units: n= 1, E=-21 n=2, E=-9 n=3, E=-4 n=4, E=-3 ...,... infinity, 0 A gaseous sample of this element is bombarded by photons of various energies (in these same units). Match each ...
Wednesday, March 19, 2014 at 10:33pm

chemistry
*the molar solubility of BaCo3 in 0.50M Bacl2 solution IS?ksp(1.6*10^-6) I CALCULATED AND GOT 3.2*10^-9 WANT TO MAKE SURE IF IT CORRECT
Wednesday, March 19, 2014 at 10:24pm

Chemistry
1. A chemist prepares a solution by dissolving 4.603 g of NaNO3 in enough water to make 200 mL of solution. What molar concentration of sodium nitrate should appear on the label? Answer in units of M 2.If the chemist mistakenly makes 225 mL of solution instead of the 200 mL, ...
Wednesday, March 19, 2014 at 9:57pm

CHEMISTRY
What is the mass in grams of one Mole of water?
Wednesday, March 19, 2014 at 9:54pm

Chemistry
If 689000 J of energy are added to 4.00 L of water at 284 K, what will the final temperature of the water be? Answer in units of K
Wednesday, March 19, 2014 at 9:50pm

Chemistry
Determine the specific heat of a material if a 34.7 g sample absorbed 45.2 J as it was heated from 293 K to 318 K. Answer in units of J/g · K Your answer must be within ± 2.0%
Wednesday, March 19, 2014 at 9:48pm

Chemistry
what is the mass in grams of one molecule of water?
Wednesday, March 19, 2014 at 9:40pm

Chemistry
How do you find the initial concentration of the acid give the titration curve of a weak acid-strong base titration?
Wednesday, March 19, 2014 at 9:22pm

Chemistry
Calculate the pH of the solution that results from mixing 30.0 mL of 0.050 M HCN(aq) with 70.0 mL of 0.030 M NaCN.
Wednesday, March 19, 2014 at 9:20pm

AP Chemistry
A solution is 1.0M in AgNO3 and Fe(NO3)2.in the electrolysis of this solution using inert electrodes, the voltage is gradually increased. What is the order in which the substances in the solution would plate our or react at the cathode ? Assume that the overvoltage of hydrogen...
Wednesday, March 19, 2014 at 8:09pm

CHEMISTRY
I need to find the rate law of a reaction but ive only done so when factors cancel out, this one has all different numbers and im not quite sure what to do with it. It has time taken every second (which im assuming are the different trials) and different concentrations of OH...
Wednesday, March 19, 2014 at 7:25pm

Organic Chemistry
Draw every stereoisomer for 1-bromo-2-chloro-1,2-difluorocyclopentan​e. Use wedge-and-dash bonds for the substituent groups, and be sure that they are drawn on the outside of the ring, adjacent to each other.
Wednesday, March 19, 2014 at 6:44pm

Chemistry
Calculate the change in mass of the In electrode after the cell supplies 100 mA of current for 10 minutes. The balanced redox reaction is 2In+Cl2=2In+ + 2Cl-. I understand the idea behind the question, I just don't know if I should use 1 mol In per 1 mol e- or 1 mol In per...
Wednesday, March 19, 2014 at 6:27pm

Chemistry
The reaction OH- + NH4+ = H20 + NH3 is kinetically first order in both reactants' concentrations. The rate constant is 2e10 1/M s. If 50 ml of .01 M NaOH is mixed with 50 ml of .01 M NH4CL, find the time required for the OH- concentration to reach 1e-4 M.
Wednesday, March 19, 2014 at 6:04pm

Chemistry
A saturated solution of MgF2 at 23 degrees C was prepared by dissolving solid MgF2 in 1 L water. The Ksp of MgF2 is 1.5e-5. a.)Calculate the mass of MgF2 dissolved. b.) When .1 mols of solid KF was dissolved in the MgF2 solution, precipitation was observed. Find the mass of ...
Wednesday, March 19, 2014 at 5:59pm

Chemistry
What is the concentration of hydronium ions in a solution that is 0.12 M HBrO(aq) and 0.160 M NaBrO(aq)?
Wednesday, March 19, 2014 at 5:56pm

Chemistry
I need to find the rate law of a reaction but ive only done so when factors cancel out, this one has all different numbers and im not quite sure what to do with it. It has time taken every second (which im assuming are the different trials) and different concentrations of OH...
Wednesday, March 19, 2014 at 5:47pm

chemistry
Calculate the H3O+ concentration present in water under the following conditions. Enter your answer in scientific notation. a. [OH-] = 2.8 x 10-7 M b. [OH-] = 8.8 x 10-3 M c. [OH-] = 2.4 x 10-11 M everytime I do the problem In the calculator I get system error someone please ...
Wednesday, March 19, 2014 at 5:05pm

Chemistry
Calculate the pH of a solution in which a. [H3O+] = 7.8 x 10-7 M pH = b. [H3O+] = 5.1 x 10-6 M pH = c. [H3O+] = 6.1 x 10-5 M pH = d. [H3O+] = 9.3 x 10-4 M pH = I get 8.1 9.5 9.1 6.7 but its wrong please someone help!
Wednesday, March 19, 2014 at 5:03pm

chemistry
I feel like this question is pretty easy, but I can't seem to figure out how to go about solving it. It's like the solution is on the tip of my tongue: Nitromethane (CH3NO2) burns in air to produce significan amounts of heat. 2 CH3NO2(l) + 3/2 O2(g) -> 2 CO2(g) + 3 ...
Wednesday, March 19, 2014 at 4:22pm

Rate Law - Chemistry
I need to find the rate law of a reaction but ive only done so when factors cancel out, this one has all different numbers and im not quite sure what to do with it. It has time taken every second (which im assuming are the different trials) and different concentrations of OH...
Wednesday, March 19, 2014 at 4:22pm

chemistry
a gas with a volume of 4.00 L at pressure of 205kPa is allowed to expand to a volume of 12.0L. what is the pressure in the container if the temp remains constant
Wednesday, March 19, 2014 at 3:49pm

Chemistry
I need to find the rate law of a reaction but ive only done so when factors cancel out, this one has all different numbers and im not quite sure what to do with it. It has time taken every second (which im assuming are the different trials) and different concentrations of OH...
Wednesday, March 19, 2014 at 3:12pm

chemistry
Knowing the concentration of a solution allows us to find all of the following except A. the mass of a solute. B. the mass of the solvent. C. the volume of the solvent. D. the concentration of a solution when conditions change.
Wednesday, March 19, 2014 at 2:19pm

Chemistry
Last week we drew Lewis dot structures of azide (N31-), a crucial component in automobile collision safety airbags. During an impact, a sensor ignites a detonator cap that sets off the following rapid reaction: 2NaN3(s) → 2Na(s) + 3N2(g) Part A What mass of ...
Wednesday, March 19, 2014 at 1:21pm

chemistry
If a tank contains 55.2 g of butane, what volume, in liters, of oxygen is needed to burn all the butane at 0.850 atm and 25 degrees Celsius? Need to show work too.
Wednesday, March 19, 2014 at 11:26am

Chemistry [back-titration] - please check my sol'n
A 7.00 gram sample containing the mineral tellurite was dissolved then treated with 70.0 mL of 0.03114 M K2CrO7. 3 TeO2 + Cr2O7 ^2- + 8 H+ -> 3 H2TeO4 + 2 Cr3+ + H2O When reaction is complete, the excess Cr2O7 2- required a 14.05 mL back titration with 0.1135 M Fe2+. ...
Wednesday, March 19, 2014 at 11:22am

Chemistry
KClO3 = KClO4 + KCl What is the conversion factor to convert between moles of potassium chlorite and moles of potassium perchlorate?
Wednesday, March 19, 2014 at 11:17am

Chemistry
I need to find the rate law of a reaction but ive only done so when factors cancel out, this one has all different numbers and im not quite sure what to do with it. It has time taken every second (which im assuming are the different trials) and different concentrations of OH...
Wednesday, March 19, 2014 at 11:15am

Chemistry
I'm having trouble trying to figure out how to setup and solve these problems: 1) 2,600.0 mL of air is at 20.0C. What is the volume at 60.0C? 2) A gas occupies 900.0 mL at a temperasture of 27.0C. What is the volume at 132.0C? 3) What change in volume results if 60.0 mL of...
Wednesday, March 19, 2014 at 11:00am

Chemistry
Calculate the number of moles of ag in 5ml of .004m agno3 and the number of moles of cr04 in 5ml of .0024m k2cro4
Wednesday, March 19, 2014 at 10:33am

Chemistry
What mass of lithium (in g) is required to react completely with 57.5mL of N2 gas at STP? Lithium reacts with nitrogen gas according to the following reaction: 6Li(s)+N2(g)→2Li3N(s)
Wednesday, March 19, 2014 at 12:45am

Chemistry
I need to vary the surface area by choosing different size beaker. I will put liquid in there so it would have to be volume??cm^3? But the question is how can I calculate the surface area of the beaker ??? The key thing here is the container... Examples: 27cm^3??? 250 ml ...
Tuesday, March 18, 2014 at 11:47pm

Chemistry
Natural gas is almost entirely methane, CH4. What volume of natural gas at 20 C and 1.00 atm pressure is required to heat one quart of water from 20 C to 100 C? The density of methane at 20 C is 0.665 g/mL. The reaction for the combustion of methane is CH4 (g) + 2 O2 (g) -->...
Tuesday, March 18, 2014 at 11:40pm

Chemistry
This compound is mescaline, a hallucinogen. Which of the following statements is true? Mescaline is an amine. Mescaline contains an alcohol group. Mescaline is a carboxylic acid. Mescaline is an amine and contains an alcohol group.
Tuesday, March 18, 2014 at 11:16pm

Chemistry
220 J to kilojoules 350 kj to calories 97.0 kcal to joules 35.0 cal to kilocalories How do I convert them?
Tuesday, March 18, 2014 at 11:02pm

Chemistry
For the reaction shown, find the limiting reactant for each of the following initial amounts of reactants. 4Cr(s)+3O2(g)→2Cr2O3(s) 1.) 1 molCr; 1 molO2 2.) 4 molCr; 2.5 molO2 3.) 12 molCr; 10 molO2 4.) 14.8 molCr; 10.3 molO2 Express your answer as a chemical formula. I&#...
Tuesday, March 18, 2014 at 10:56pm

Chemistry
Hello! I'm doing these questions for my chemistry homework, and I can only figure out the first one, I don't know how to do the rest, I'm completely stuck! Please help!! Thank you! 1.) For the reaction, calculate how many grams of the product form when 18.4g of Ca ...
Tuesday, March 18, 2014 at 10:55pm

chemistry
Sometimes the basicity of a solution is reported using pOH (pOH = -log[OH-]). What is the a. [OH-] if pOH = 1.90 b. [H3O+] if pOH = 12.94 c. pH if pOH = 9.70
Tuesday, March 18, 2014 at 10:42pm

chemistry
It requires 23.2 mL of 0.250 M KOH to titrate 49.0 mL of an HCl solution of unknown concentration. Calculate the initial HCl concentration.
Tuesday, March 18, 2014 at 10:39pm

chemistry
C6O2H8, Ka = 1.7 x 10-5 calculate pka
Tuesday, March 18, 2014 at 10:36pm

Chemistry
What is the concentration of H3O+ in a solution with the following pH values. Enter your answer in scientific notation. a. 6.66 b. 13.40 c. 13.17 d. 2.39
Tuesday, March 18, 2014 at 10:15pm

Chemistry
Suppose you tried to carry out a double replacement reaction by mixing equal voulumes of a solution that contains dissolved NAOH and a solution that contains dissolved NACL. WHat would you expect to happen when the two solutions were mixed? Expain?
Tuesday, March 18, 2014 at 10:12pm

General Chemistry
Sodium sulfate is slowly added to a solution containing 0.0500 M Ca2 (aq) and 0.0290 M Ag (aq). What will be the concentration of Ca2 (aq) when Ag2SO4(s) begins to precipitate?What percentage of the Ca2 (aq) can be separated from the Ag (aq) by selective precipitation?
Tuesday, March 18, 2014 at 10:07pm

chemistry
what type of bonding is phosphoric acid?
Tuesday, March 18, 2014 at 9:49pm

chemistry
in which of the following pairs of compiunds are both members of the pair ionic compounds? a) PI3 and HBr, b) H2S and NCl3, c)LiF and H2O, d)LiI and NiO
Tuesday, March 18, 2014 at 9:42pm

Chemistry
The Ksp of tin(II) hydroxide, Sn(OH)2, is 5.45 × 10-27. Calculate the solubility of this compound in g/L.
Tuesday, March 18, 2014 at 9:23pm

Chemistry
What does each electron outside of a nucleus occupy?
Tuesday, March 18, 2014 at 6:17pm

Chemistry
What is the enthalpy change if 25.0 g of methane are burned? 890kJ of heat released for every mole of methane that reacts. CH4 + 2O2 = CO2 + 2H2O
Tuesday, March 18, 2014 at 5:31pm

Science/Chemistry
Is this equation balanced? Does it show that no atoms are lost or gained in chemical reactions? 8Fe + S8 --->8FeS
Tuesday, March 18, 2014 at 4:53pm

CHEMISTRY
The data below has been taken for the reaction of a dye with the hydroxide ion. The reaction was performed at two different hydroxide ion concentrations while the dye concentration was kept constant. What is the rate law? [OH─] = 0.10 M [OH─] = 0.20 M t (min) Abs ...
Tuesday, March 18, 2014 at 4:23pm

chemistry
In the following reaction, how many liters of oxygen produce 560 liters of carbon dioxide in the oxidation of methane, given that both gases are at STP? CH4 + 2O2 ¨ CO2 + 2H2O
Tuesday, March 18, 2014 at 4:07pm

Chemistry
Consider the following hypothetical nuclear breakdown: Fermium-258 (Fm-258) loses three alpha particles and two neutrons. What is the new element that is formed (in terms of chemical symbol, atomic number and atomic mass)? I'm not sure how to express this in equation form...
Tuesday, March 18, 2014 at 3:00pm

Chemistry
A reaction has a standard free-energy change of –10.30 kJ mol–1 (–2.462 kcal mol–1). Calculate the equilibrium constant at 25ºC.? This is what I've done so far.. ∆Gº= -2.3 RT + log (K) -10.31 kJ = -2.3 (.0083145)(298) + log K -10.31 kJ...
Tuesday, March 18, 2014 at 2:52pm

Chemistry
It is commonly known that freshly cut fruits turn a brownish color when exposed to the air for a number of minutes. This is due to the action of the enzyme polyphenoloxidase. It is also well known that the formation of the brown color can be prevented or slowed by chilling the...
Tuesday, March 18, 2014 at 1:38pm

Chemistry
a 2.500 g sample of a pure compound was analysed and found to contain 1.094 g of nitrogen.determine whether the compound is either NH4NO3 or NH4NO2 .show all by calculations.
Tuesday, March 18, 2014 at 1:22pm

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