Tuesday
July 29, 2014

Posts by Sarah H


Total # Posts: 32

Chem -plz check work
so i've worked on this some more, now I am asking if someone will plz check my work 2 half cells in a galvanic cell consist of one iron Fe(s) electorde in a solution of iron (II) sulphate FeSO4(aq)and a silver Ag(s) electrode in a silver nitrate solution, a)state the oxida...

grade 12 chemisstry
I have no idea what I'm doing here, please help. 2 half cells in a galvanic cell consist of one iron Fe(s) electorde in a solution of iron (II) sulphate FeSO4(aq)and a silver Ag(s) electrode in a silver nitrate solution, a)state the oxidation half reaction, the reduction h...

grade 12 chem - check my answer again please
Hi, please check my work: In an experiment, 23.4 g of FES are added to excess oxygen and 16.5 g of FE2O3 are produced. The balanced equation is: 4FeS + 7O2 --> 2Fe2O3 + 4SO2 Calculate the % yield. My Answer: nFeS=23.4g/87.92 g/mol =0.266 mol 4mol FeS / 0.266 mol = 7mol O2/ ...

chem - CHECK PLEASE BOB PURSLEY
I MEAN ETHYLENE GLYCOL, SORRY.

chem - CHECK PLEASE BOB PURSLEY
not ethelyne glycol?

chem
what is the common name for ethane and propene? I think propene is propylene but i don't know about ethane.

gr. 12 chemistry
Hi, please check my work: In an experiment, 23.4 g of FES are added to excess oxygen and 16.5 g of FE2O3 are produced. The balanced equation is: 4FeS = 7O2 --> 2Fe2O3 + 2SO2 Calculate the % yield. My Answer: nFeS=23.4g/87.92 g/mol =0.266 mol 4mol FeS / 0.266 mol = 7mol O2/ ...

Chemistry - Bob Pursley
Posted by Sarah H on Friday, May 23, 2008 at 8:10pm. Hi, please check my work: In an experiment, 23.4 g of FES are added to excess oxygen and 16.5 g of FE2O3 are produced. The balanced equation is: 4FeS = 7O2 --> 2Fe2O3 + 2SO2 Calculate the % yield. My Answer: nFeS=23.4g/87...

Chemistry - please help
Hi, please check my work: In an experiment, 23.4 g of FES are added to excess oxygen and 16.5 g of FE2O3 are produced. The balanced equation is: 4FeS = 7O2 --> 2Fe2O3 + 2SO2 Calculate the % yield. My Answer: nFeS=23.4g/87.92 g/mol =0.266 mol 4mol FeS / 0.266 mol = 7mol O2/ ...

Chemistry - please help
Hi, please check my work: In an experiment, 23.4 g of FES are added to excess oxygen and 16.5 g of FE2O3 are produced. The balanced equation is: 4FeS = 7O2 --> 2Fe2O3 + 2SO2 Calculate the % yield. My Answer: nFeS=23.4g/87.92 g/mol =0.266 mol 4mol FeS / 0.266 mol = 7mol O2/ ...

chemistry-please check my work
Determine the mass of carbon monoxide that is produced when 45.6 g of methane CH4 react with 73.2 g of oxygen gas, O2. The products are CO and H2O. Please check my work: CH4 + 3O2 ---> 2CO + 2H20 nCH4=2.84 mol nO2=4.58 mol Limiting Reactant: 1 mol CH4/2.84 mol CH4 = 3 mol O...

chemistry - please help!
#1) how many atoms are represented by 2.0 mol of carbon? I think 12.01 x 10^23 #2) Calculate the # of atoms of each element present in 3.67 mol of H^2SO^4...I have no idea how to do this one?

Gen Chem
The signs of DG, DH, and DS at 25°C are shown in the table below for three reactions. Reaction DG DH DS I - + + II - - + III - - - Which reaction or reactions should go in the REVERSE direction at high temperature?

Gen Chem
That makes sense, just so I understand, how did you get 8.666 g Cr? What does the +6 to 0 mean?

Gen Chem
Chromium can be electroplated from an aqueous solution containing sulfuric acid and chromic acid, H2CrO4. What current is required to deposit chromium at a rate of 1.25 g/min? 1mol H2CrO4 has 51.996 grams current= coulomb/sec How do I convert to get coulombs from the problem?

Gen Chem
Consider the following reaction, A <===> B in a 1.00L container. At 1.77°C, the molar concentrations of A and B, respectively, 5.838M and 3.945M. Suddenly, 8.744 moles of A are added to the system. What is the change in DG of the system? Give the answer in kJ?

Gen Chem
A liquid is heated from 33.96°C to 104.32°C. The vapor pressure increases from 23.54torr to 984.35torr. What is the heat of vaporization of the liquid in kJ/mol? The change in temperature is 70.36°C. Change in vapor pressure = 960.76 torr. What is the equation to f...

Gen Chem
If Q=.61259, what is the formula to convert to pQ? Is it pQ=lnQ?

Gen Chem
n = 6 and E° = 0.011v for a redox reaction with Q = 7.03 x 10-1. Calculate E. Assume T = 298.15K. So I did E=E°-(RT/nF)lnQ Since the temp is 298.15, I substituted0.02569 for (RT/F) and got 0.011v-(0.0259/6)lnQ and got -.002355 Is that correct?

Gen Chem
Consider a cell based on the following reaction: GeO(s) + H2O(l) + 2 Ag+(aq) ===> GeO2(s) + 2 H+(aq) + 2 Ag(s) If [Ag+] = 1 M, at 25°C, would it be..... pH = 2 ( E° - E ) / 0.059159 V. or pH = ( E° - E ) / 0.059159 V.

Gen Chem
so n=10 then, right? 2Mn atoms (2*5), and 1*10 for the Cl...?

Gen Chem
So is n=5 then? (7-1)+(-1-0)? or (7-1)+(|-1-0|) then n=7? My choices are 2, 4, 5, 10, 16...

Gen Chem
What is n, the number of moles of electrons transferred, in the following reaction? 2 MnO4-(aq) + 16 H+(aq) + 10 Cl-(aq) ===> 2 Mn2+(aq) + 5 Cl2(g) + 8 H2O(l).

Gen Chem
How can I figure the equivalents of Cu deposited and then the number of coulombs?

Gen Chem
A current is passed through two cells connected in series. The half-reactions occurring at the cathode of each cell are TcO4-(aq) + 8 H+(aq) + 7 e- ===> Tc(s) + 4 H2O(l) and Cu2+(aq) + 2 e- ===> Cu(s). If 4.40 g of copper are deposited in the second cell, how much techne...

Gen Chem
Neptunium-239 has a half-life of 2.35 days. How many days must elapse for a sample of 239-Np to decay to 1.00% of its original quantity? I got: close to 15 days. Is this right? I figured that about 1% of the original quantity would be roughly 6.5 Half lives, and since a half l...

Gen Chem
Consider the following reaction, A <===> B in a 1.00L container. At 1.77°C, the molar concentrations of A and B, respectively, 5.838M and 3.945M. Suddenly, 8.744 moles of A are added to the system. What is the change in DG of the system. Give the answer in kJ?

Gen Chem
n = 6 and E° = 0.011v for a redox reaction with Q = 7.03 x 10-1. Calculate E. Assume T = 298.15K. How do I set this equation up?

Gen Chem
It can be more than one of these choices, its a "check all that apply" question. Are there any other options that must apply for S=0??

Gen Chem
Which of the following conditions MUST be true for the entropy of a pure solid to be zero? a) T must be 0 K b) The solid must be crystalline and not amorphous c)the solid must be perfectly ordered d) the solid form must be an element

Gen Chem
Which provides the greatest increase in entropy for a mole of substance? a)Water melts at 0°C. b)Liquid water is heated from 0°C to 25°C. c)Gaseous water is converted to solid ice at 0.1°C. d)Water is converted from liquid to vapor at 100°C. e)Cannot be det...

Gen Chem
What is the number of nucleons in 236-U2+?

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