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April 19, 2014

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

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Chemistry 2
BaCl2 + Na2SO4 ---> BaSO4 + 2NaCl Ba++ + 2Cl- +2Na+ + SO4-- --> BaSO4 + 2 Na+ + 2Cl- Na+ and Cl- same both sides so net: Ba++ + SO4-- ---> BaSO4
Monday, March 3, 2014 at 3:26pm

chemistry
Write the net ionic equation for the following molecular equation. CoI2(aq) + K2CO3(aq) CoCO3(s) + 2KI(aq)
Monday, March 3, 2014 at 3:26pm

Chemistry 2
is this for ashworth??
Monday, March 3, 2014 at 3:18pm

chemistry
Write the net ionic equation for the following molecular equation. HBr is a strong electrolyte. HClO is a weak electrolyte. KClO(aq) + HBr(aq) KBr(aq) + HClO(aq)
Monday, March 3, 2014 at 3:18pm

Chemistry 2
For the fist order reaction A <-> B, calculate the t1/2(half life) and k(rate constant) and also fill in the blanks. A-Concetration t-time 20 0 10 ? 5 40 sec 3 ? ? 500 sec t1/2=? k=?
Monday, March 3, 2014 at 3:13pm

Chemistry 2
Thanks man i appreciate it
Monday, March 3, 2014 at 3:08pm

Chemistry 2
When we mix 25.0 mL, 2.0 M BaCl2 with 25.0 mL, 3.0 M Na2SO4 what is the balanced equation? What is the ionic equation? what is the net ionic equation?
Monday, March 3, 2014 at 2:52pm

Chemistry 2
For the reaction: 2A + 3B <--> 4C Kinetic data are as follows A B time needed 10mL 5mL 720 seconds 20mL 5mL 180 seconds 20mL 10mL 90 seconds 30mL 20mL ?? The rate of the equation is?
Monday, March 3, 2014 at 2:44pm

chemistry
13.3
Monday, March 3, 2014 at 2:35pm

chemistry
The problem doesn't say that the 1.00 g sample is pure; I'll assume it is. mols Pt = 0.5780/195 = about 0.00296 but you need to do ALL of these calculations more carefully. g Cl = 1.00-0.5760 = 0.422g and convert to mols = approx 0.012 So the empirical formula is PtCl4...
Monday, March 3, 2014 at 2:17pm

Chemistry 2
Al2(SO3)3 2 Al = 54 3 S = 96 9 O = 144 -----------add 294 grams/mol so 80 grams is 80/294 = 0.272 mol of aluminum sulfite in 50 mL a liter is 1000 mL 0.272 *1000/50 = 5.44 mols/liter
Monday, March 3, 2014 at 2:12pm

Chemistry 2
What is the molarity of 50.0 mL solution of aluminum sulfite that contains 80.0 g of this salt? (Al=27.0, S=32.0,O=16.0)
Monday, March 3, 2014 at 2:04pm

Chemistry
mmols benzoic acid = mL x M = 160.0 x 0.17 = approx 27 but you need to do it more accurately. pH = pKa + log (base)/(acid) You will need to look up the pKa for benzoic acid. Substitute pKa, (base) = x, (acid) = 27, pH = 4.30, and solve for x = benzoate x = mmols benzoate. ...
Monday, March 3, 2014 at 1:50pm

Chemistry
What mass of sodium benzoate should be added to 160.0mL of a 0.17M benzoic acid solution in order to obtain a buffer with a pH of 4.30?
Monday, March 3, 2014 at 1:27pm

chemistry
also, what is the experimental percent of platinum in the original compound?
Monday, March 3, 2014 at 12:16pm

chemistry
a 0.2000 grams sample of aluminum metal is added to a solution containing 1.0000grams of an unknown compound made of platinum and chloride ion. the reaction results in the formation of aluminum chloride and platinum metal. when the reaction is complete, unreacted aluminum ...
Monday, March 3, 2014 at 11:51am

Chemistry
You're having trouble with the basics. I can point out some of the problems taken one at a time. With the decomposition you appear not to understand how to write atoms and molecules. The correct symbolism is: Example: the decomposition reaction of hydrogen sulfide Is it ...
Monday, March 3, 2014 at 11:51am

Chemistry
I am learning the different types of chemical reactions synthesis, decomposition, single displacement, and double displacement I am also learning skeletal equations word equations and balancing the equations I know how to balance equations if I am given the formula in symbols ...
Monday, March 3, 2014 at 11:29am

chemistry
!@#$%^& you mathar fakers
Monday, March 3, 2014 at 9:33am

Chemistry
Henry's Law says: Pressure(gas)=(Henry's Law Constant)(Molarity of the gas)… we are looking for Molarity so we can rewrite the above equation as… Molarity of the gas=Pressure(gas)/(Henry's Law Constant) so… M=1.95 bar/29.4 barM-1 the bar units cancel...
Monday, March 3, 2014 at 1:30am

Chemistry
Its 2. I had this question on a quiz
Monday, March 3, 2014 at 12:55am

Chemistry
Oh okay, thankyou!
Monday, March 3, 2014 at 12:36am

Chemistry
No, 20 km is a distance, not a pressure. The problem says the balloon is relesed at sea level on earth's surface. Pressure at sea level is 101.325 kPa or 1 atm or 14.7 lb/sq ft. Since you are using kPa for the second P you should use first P in the same units.
Monday, March 3, 2014 at 12:26am

Chemistry
I know I'm suppose to use 3.86934 as the first volume and 10 kPa as the second pressure, but what am I suppose to use as the first pressure? Am I suppose to use 20.0 km?
Monday, March 3, 2014 at 12:11am

Chemistry
Assuming the T is constant (which it will not be) use p1v1 = p2v2
Sunday, March 2, 2014 at 11:53pm

Chemistry
A weather balloon with a volume of 3.86934 L is released from Earth’s surface at sea level.What volume will the balloon occupy at an altitude of 20.0 km, where the air pressure is 10 kPa? Answer in units of L
Sunday, March 2, 2014 at 11:43pm

Chemistry
25% v/v means 25.0 g isopropyl alcohol in 100 mL solution. mols C3H8O = grams/molar mass Convert 100 mL of the solution to grams using density, then M = mols/L soln.
Sunday, March 2, 2014 at 11:40pm

Chemistry
What is the molarity of a 25.0% (v/v) aqueous isopropyl alcohol solution? the density of isopropyl alcohol ( C3H8O, molar mass 60.1g/mol) is 0.786g/ml
Sunday, March 2, 2014 at 11:32pm

chemistry
2S2O3^2- + I2 ==> 2I^- + S4O6^2- 1. mols I2 = M x L = ? 2. Convert mols I2 to mols S2O3^2-. That is ?mols I2 x (2 mol S2O3^2-/1 mol I2) = ? 3. Then M S2O3^2- = mols S2O3^2-/L S2O3^2-
Sunday, March 2, 2014 at 11:07pm

Chemistry: Check my answers please!
I don't agree with #1 but I do the others. I think the results will be low if I've interpreted the question correctly and this is not a standard additions method. I can't draw it on this board but here is what you do. On a sheet of graph paper, mark the Y axis as A...
Sunday, March 2, 2014 at 11:03pm

chemistry
Sodium thiosulfate, Na2S2O3, is used as a fixer in photographic film developing. The amount of Na2S2O3 in a solution can be determined by a titration with iodine, I2, according to the equation: 2Na2S2O3(aq) + I2(aq) --> Na2S4O6 +2NaI(aq). Calculate the concentration of the ...
Sunday, March 2, 2014 at 10:53pm

college chemistry
poo poo
Sunday, March 2, 2014 at 10:50pm

Chemistry
27.8g KCl/molar mass KCl = approx 0.37 0.37/0.7 = approx 0.53M AgNO3 + KCl ==> AgCl + KNO3 mols KCl used = M x L = 0.0221 x 0.53 = ? mols AgNO3 = the same (since the ratio in the balanced equation is 1:1). Then M AgNO3 = mols AgNO3/L AgNO3.
Sunday, March 2, 2014 at 10:29pm

Chemistry
A solution is prepared by placing 27.8 g of KCl in a 0.700 L volumetric flask and adding water to dissolve the solid, then filling the flask to the mark. What is the molarity of an AgNO3 solution if 22.1 mL of the KCl solution react exactly with 43.0 mL of the AgNO3 solution?
Sunday, March 2, 2014 at 10:21pm

College Chemistry - Science
I really don't understand the problem. What are you to judge by? Of course you can deprotonate half of it if you add enough NaOH. If you add enough NaOH I should think you could deprotonate all of the HPO4^2-. But I don't know how you would tell when you were there ...
Sunday, March 2, 2014 at 10:02pm

cHEMISTRY
Yes, KClO3 is potassium chlorate. The best thing I can tell you to memorize the polyatomic ions. For example, ClO3^- is chlorate SO4^2- is sulfate NO3^- is nitrate etc. Here is a table. Time and usage will makes this easier. https://www.google.com/search?q=polyatom​ic+...
Sunday, March 2, 2014 at 9:57pm

Chemistry
density x gravity x height = pressure g/cc.......9.8.......m.......kPa #1. 1.0 x 9.8 x h = (762/760)*101.325 2. You substitute.
Sunday, March 2, 2014 at 9:48pm

cHEMISTRY
i dont know how to write chemical formulas is it like nomenclature because i need to balance equations (which i know how if the equation is given to me the symbols type but not in words), i need to write skeletal equations but i dont know if they are correct. example: 2H2+O2-&...
Sunday, March 2, 2014 at 9:48pm

College Chemistry - Science
In an acid-base experiment at 25.0°C, a sodium hydroxide solution was standardized against KHP. The average value for the concentration of the sodium hydroxide solution was calculated to be 0.0125 M. This solution was used to titrate the phosphoric acid present in coke. ...
Sunday, March 2, 2014 at 9:25pm

Chemistry
1.If the atmosphere can support a column of mercury 762 mm high at sea level, what height of water could be supported? The density of water is approximately 114 that of mercury.Answer in units of mm 2.If the atmosphere can support a column of mercury 762 mm high at sea level, ...
Sunday, March 2, 2014 at 9:07pm

College Chemistry - Science
Thank you so much! Not it makes sense!
Sunday, March 2, 2014 at 8:27pm

College Chemistry - Science
pH 11.95 means pOH = 2.05 pOH = -log(OH^-) (OH^-) = 0.00891 0.00891 x 30 mL = about 0.27 (Note: Calculations give this as 0.267 but I've rounded to 0.27 because you're allowed only two significant figures.) mmols acid = 45 x 0.002 = 0.09 CH3COOH + NaOH ==> CH3COONa...
Sunday, March 2, 2014 at 8:25pm

Chemistry
to get rate you need to get the slope of the graph
Sunday, March 2, 2014 at 8:13pm

College Chemistry - Science
At room temperature (25°C), 45 mL of a 0.002 M acid solution reacts with 30 mL of a NaOH (aq) solution (pH = 11.95), determine (through calculations) whether the acid is phosphoric acid (H3PO4), acetic acid (CH3COOH), or carbonic acid (H2CO3).
Sunday, March 2, 2014 at 7:54pm

Chemistry - Science
In an acid-base experiment at 25.0°C, a sodium hydroxide solution was standardized against KHP. The average value for the concentration of the sodium hydroxide solution was calculated to be 0.0125 M. This solution was used to titrate the phosphoric acid present in coke. ...
Sunday, March 2, 2014 at 7:49pm

chemistry
H2SO4 + 2NaOH ==> Na2SO4 + 2H2O mols NaOH = M x L = ? mols H2SO4 = 2x mols NaOH (look at the coefficients n the balanced equation.)_ M H2SO4 = mols H2SO4/L H2SO4
Sunday, March 2, 2014 at 7:27pm

chemistry
I answered this earlier.
Sunday, March 2, 2014 at 7:24pm

chemistry
1. acid + base = salt + water 2HCl + Mg(OH)2 ==> 2H2O + MgCl2 You add the phases. 2. Pb(NO3)2 + Na2S ==> PbS(s) + 2NaNO3(aq) You add the other phases. 3. Pb^2+(aq) + S^2-(aq) ==> PbS(s)
Sunday, March 2, 2014 at 7:23pm

chemistry
A 25.0-mL sample of H2SO4 is neutralized with NaOH. What is the concentration of the H2SO4 if 35.0 mL of 0.150 M NaOH are required to completely neutralize the acid?
Sunday, March 2, 2014 at 7:14pm

chemistry
What is the product for Ni(s) + 2Na^+? I don't think this is possible. Am I wrong?
Sunday, March 2, 2014 at 7:11pm

Chemistry
How many mols do you want? That's M x L = ?mols. Then mol = grams/molar mass. I think the point of this question is how to physically describe how it is prepared. Weigh that many grams NaCl, add to a 500 mL volumetric flask, add some water, swirl until all of the NaCl is ...
Sunday, March 2, 2014 at 7:05pm

Chemistry
[Al2(SO4)3] = 0.200M x (15.00/50.00) = ? Then [SO4^2-] = 3x that.
Sunday, March 2, 2014 at 7:01pm

Chemistry
Predict the prdeucts of the following acid/base and precipitation reactions and balance the equations. Remeber to indicate (s), (l) or (aq Q1. HCI(aq) + Mg(OH)2(aq)----> Q2. Pb(NO3)2(aq)+ Na2S (aq)---> Q3. write the ionic equation for question 2. Can you let me know how ...
Sunday, March 2, 2014 at 7:01pm

Chemistry
Read the problem. "Divers know that the pressure exerted by the water increases about 100 kPa with every 10.2 m of depth. This means that at 10.2 m below the surface, the pressure is 201 kPa;" So the pressure 10.2m below is 100 + whatever it is at the surface (which ...
Sunday, March 2, 2014 at 6:57pm

chemistry
Predict the prdeucts of the following acid/base and precipitation reactions and balance the equations. Remeber to indicate (s), (l) or (aq Q1. HCI(aq) + Mg(OH)2(aq)----> Q2. Pb(NO3)2(aq)+ Na2S (aq)---> Q3. write the ionic equation for question 2.
Sunday, March 2, 2014 at 6:57pm

Chemistry
describe how you would prepare 500.0 ml of 0.400M NaCl solution, starting from solid NaCl
Sunday, March 2, 2014 at 6:50pm

Chemistry
Determine the sulfate ion concentration in a solution prepared by diluting 15.00mL of a 0.200M aluminum sulfate solution with 35.00mL of water. Assume the volumes are additive.
Sunday, March 2, 2014 at 6:49pm

Chemistry
Why do I need to add 101?
Sunday, March 2, 2014 at 6:27pm

Chemistry
So the new pressure is 101 + (100*40.32/10.2) = ?. Then p1v1 = p2v2
Sunday, March 2, 2014 at 6:19pm

Chemistry
When you use the spectrophotometer you insert the cuvette containing the blank and use the adjustment knob to make the needle read 100 %T. That is for no Cr solution in the beam. That adjustment takes care of any reflections from the liquid, from the walls of the cuvette, and ...
Sunday, March 2, 2014 at 6:10pm

Chemistry
Divers know that the pressure exerted by the water increases about 100 kPa with every 10.2 m of depth. This means that at 10.2 m below the surface, the pressure is 201 kPa; at 20.4 m below the surface, the pressure is 301 kPa; and so forth. If the volume of a balloon is 3.2 L ...
Sunday, March 2, 2014 at 6:10pm

chemistry
mols H2O = grams/molar mass = ? Then 1 mol contains 6.02E23 so ? mols will contain .....
Sunday, March 2, 2014 at 5:59pm

chemistry
calculate the number of molecules found in 4.50 g of water
Sunday, March 2, 2014 at 5:53pm

Chemistry
3) A student mistakenly uses the cuvette containing the most dilute standard solution, rather than the cuvette containing deionized water, as the blank solution. I don't understand why there would be lower concentration of Cr(VI) ion...
Sunday, March 2, 2014 at 5:20pm

Chemistry: Check my answers please!
How would each of the following affect the Cr(VI) concentration determined in this experiment? Justify the answers with an explanation. In the experiment, absorption spectroscopy was used to obtain the concentration of Cr(VI) ions. 1) A student adds more standard solution than...
Sunday, March 2, 2014 at 4:38pm

Chemistry
What number is the rate ?
Sunday, March 2, 2014 at 3:20pm

no equilibrium---Chemistry

Sunday, March 2, 2014 at 3:09pm

chemistry
1 mol has 6.02E23 so 0.4 mol will have .....
Sunday, March 2, 2014 at 3:08pm

Chemistry
Use any one of the points of experimental data. Plug in [O2], [NO2] and the rate, solve for k.
Sunday, March 2, 2014 at 3:07pm

Chemistry
Did anyone end up getting this. if you plug in the numbers above you still need the retain rate to find k. How do you do that??!!
Sunday, March 2, 2014 at 2:52pm

Chemistry
An atmospheric scientist interested in how NO is converted into NO2 in urban atmospheres carries out two experiments to measure the rate of this reaction. The data are tabulated below. A: [NO]0 = 9.63 × 10-3 M, [O2]0 = 4.1 × 10-4 M t(s) 0/3.0/6.0/9.0/12.0 [O2] 4.1/...
Sunday, March 2, 2014 at 2:51pm

Chemistry
Did anyone end up getting this. if you plug in the numbers above you still need the retain rate to find k. How do you do that??!!
Sunday, March 2, 2014 at 2:50pm

chemistry
How many molecules are in 0.400 moles of N2 O5?
Sunday, March 2, 2014 at 2:29pm

Chemistry
How would applying an external pressure on the following equilibrium affects the distribution of iodide between the polar (aqueous) and non polar (varsol)
Sunday, March 2, 2014 at 12:29pm

chemistry
there is a 2 a 2 not 1 but 2KClO3→ 2KCl + 3O2
Sunday, March 2, 2014 at 11:33am

Chemistry: HELP! PLEASE
a) Addition of Na2S2O3 to I2+I-->I3 in an aqueous layer will turn the solution clear and colourless. Write an equation explaining this observed colour. b) Addition of Na2S2O3 to I2+I-->I3 in an varsol layer will turn the solution pink. Write and equation explaining this ...
Sunday, March 2, 2014 at 11:28am

Chemistry
I saw yellow thick cloudy liquid but no precipitate
Sunday, March 2, 2014 at 10:37am

Chemistry
How would one be able to identify the lambda max of Cr(III) at a concentration less than 70ppm from a graph? I couldn't post the graph, but I don't understand how one would be able to do this? The graph had the Chromium Absorbance Spectra of 70ppm for Cr(VI) and Cr(III...
Sunday, March 2, 2014 at 1:02am

Chemistry
How would one be able to identify the lambda max of Cr(III) at a concentration less than 70ppm from a graph? I couldn't post the graph, but I don't understand how one would be able to do this? The graph had the Chromium Absorbance Spectra of 70ppm for Cr(VI) and Cr(III...
Sunday, March 2, 2014 at 12:57am

Chemistry
How would each of the following affect the Cr(VI) concentration determined in this experiment? Justify the answers with an explanation. In the experiment, absorption spectroscopy was used to obtain the concentration of Cr(VI) ions. 1) A student adds more standard solution than...
Sunday, March 2, 2014 at 12:47am

chemistry
1.Zn metal in MnSO4 Zn metalin AgNO3 Mn metal in Zn(NO3)2 Mn metal in AgNO3 Ag metal in Zn(NO3)2 Ag metal in MnSO4. 2. Is the note about complex ion formation your observation or is that a part of the question. The most likely products are Cu(OH)2 and Mg(OH)2. Mg(OH)2 is not ...
Sunday, March 2, 2014 at 12:38am

chemistry
1) List a series of tests that would determine the order of activity (least active to most active) for Zn, Mn, and Ag. 2) What would be the reaction for the addition of excess OH- ions to Mg(NO3)2 and Cu(NO3)2? This is a complex ion forming reaction. Would the complete ionic ...
Sunday, March 2, 2014 at 12:21am

chemistry
I did that for you below but I corrected the typos. 2Cr^3+(aq) + 3CO3^2-(aq) ==> Cr2(CO3)3(s)
Sunday, March 2, 2014 at 12:12am

oops--my typo--Chemistry
2Cr^3+(aq) + 3CO3^2-(aq) ==> Cr2(CO3)3(s)
Saturday, March 1, 2014 at 10:31pm

Chemistry
I will assume you had those typos and the equation is 2CrI3(aq)+3Na2CO3(aq) ---> Cr2(CO3)3(s) + 6NaI(aq) 2Cr^3+(aq) + 6I^-(aq) + 6Na^+(aq) + 3CO3^2-(aq) ==> Cr2(CO3)3(s) + 6Na^+(aq) + 6I^-(aq) 6I^- cancel 6Na^+ cancel which leaves the net ionic equation as 2Cr^3+(aq) + ...
Saturday, March 1, 2014 at 10:29pm

Chemistry
sorry your right its 2Crl3(aq) and 3NA2CO3(aq) apologies for the error.
Saturday, March 1, 2014 at 10:25pm

Chemistry
I think you have some typos. Is that CrI3(aq)? Is that Na2CO3?
Saturday, March 1, 2014 at 10:21pm

chemistry
write the net ionic equation for the following molecular equation. 2Crl(aq)+3NaCO3(aq) ---> Cr2(CO3)3(s) + 6NaI(aq)
Saturday, March 1, 2014 at 10:20pm

Chemistry
how u explained the last post, can u please explain in details like that for this question. write the net ionic equation for the following molecular equation. 2Crl(aq)+3NaCO3(aq) ---> Cr2(CO3)3(s) + 6NaI(aq)
Saturday, March 1, 2014 at 10:11pm

Chemistry
I got that answer wrong. You was right I didnt need H2O
Saturday, March 1, 2014 at 9:57pm

Chemistry
I think my last post shows how I arrive at th final answer. The rules are 1. write the molecular equation. 2. Break the molecules into ions. a. strong electrolytes become all ions. b. solids (precipitates and there are none in this equation) are written as (s) for solids) and ...
Saturday, March 1, 2014 at 9:40pm

Chemistry
Thank you! i will try that and see if i get it right and let you know of the outcome. Than you for your help much appreciated..
Saturday, March 1, 2014 at 9:36pm

Chemistry
CH3COONa(aq) + HNO3(aq) ==> NaNO3(aq) + CH3COOH(aq) If we convert all of that to an ionic equation we have CH3COO^-(aq) + Na^+ + H3O^+ + NO3^-(aq) ==> Na^+(aq) + NO3^-(aq) + C3COOH(aq) Na^+(aq) cancels. NO3^-(aq) cancels. We are left with CH3COO^-(aq) + + H3O^+(aq) ==>...
Saturday, March 1, 2014 at 9:30pm

Chemistry
Also i would be very grateful if u can explain how u got the answer so i know how to work it out in future please.
Saturday, March 1, 2014 at 9:27pm

Chemistry
so i should have CH3COO^- + H^+ ==> CH3COOH +H2O??? as my online test has four boxes
Saturday, March 1, 2014 at 9:12pm

Chemistry
There is no other "answer" unless you want to include H2O as the other answer. I don't think that's necessary. Since you're using H^+ for H3O^+ that leaves a H2O for the right (but I think all of that is taken care of by the (aq) phases.
Saturday, March 1, 2014 at 9:05pm

chemistry
what is the net ionic equation for the following molecular equation. HNO3 is strong electrolyte and CH3COOH is weak electrolyte. NaCH3COO(aq)+HNO3(aq)----->NaNO3(aq)+​CHOOH(aq) the same question says use H+ for the hydronium ion, CH3OOH for acetic acid and CH3COO for ...
Saturday, March 1, 2014 at 9:00pm

Chemistry
the same question says use H+ for the hydronium ion, CH3OOH for acetic acid and CH3COO for the acetate ion. answer + answer---> answer + answer it has four boxes, pretend the answer is one box. i hope this helps
Saturday, March 1, 2014 at 8:42pm

Chemistry
how do you get the rate?
Saturday, March 1, 2014 at 8:39pm

Chemistry
See your other post.
Saturday, March 1, 2014 at 8:24pm

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