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April 23, 2014

Search: Chemstry

Number of results: 58

Chemistry
There origenal chemistry,electrical chemstry,biology chemstyry,physical chemstry
Monday, October 3, 2011 at 10:16pm by Mr Eng Ibrahem

chemstry
dfgsdf
Friday, January 28, 2011 at 8:42pm by adsdf

Chemstry
hey
Monday, April 28, 2008 at 8:32pm by Anonymous

chemstry
267.2 WHAT?
Sunday, March 16, 2014 at 7:36pm by DrBob222

chemstry
iron(II)
Sunday, March 2, 2008 at 9:20pm by DrBob222

Chemstry
2.2345x10^-2kg
Wednesday, August 31, 2011 at 11:11pm by Jackie Chan

chemstry
identify the composition of each form
Wednesday, December 1, 2010 at 9:22pm by hadi daibs

chemstry
identify the composition of each form
Wednesday, December 1, 2010 at 9:22pm by hadi daibs

chemstry
identify the composition of each form
Wednesday, December 1, 2010 at 9:22pm by hadi daibs

chemstry
Surely this is in your text/notes.
Monday, January 21, 2013 at 5:49pm by DrBob222

chemstry
See your post above.
Thursday, October 31, 2013 at 10:14am by DrBob222

chemstry
with what? air? water? dirt? gasoline?
Friday, February 26, 2010 at 12:26pm by DrBob222

science
i need help with chapter 5.1 for a chemstry review.
Thursday, March 3, 2011 at 8:36pm by marie

Chemstry
moles = M x L M = 37.6 mM/1000
Sunday, May 1, 2011 at 8:26pm by DrBob222

chemstry
name Fe 2+ according to the stock system
Sunday, March 2, 2008 at 9:20pm by john

chemstry
the reaction of fe(metalic) in sponge iron
Friday, February 26, 2010 at 12:26pm by vibek

chemstry
How could you tell if a compound consistd of ions if it does not dissolve in water?
Friday, March 28, 2008 at 5:32pm by ss

chemstry
Melt it and see if the molten salt conducts electricity.
Friday, March 28, 2008 at 5:32pm by DrBob222

Chemstry Help Drbob!
See my response to your first post below.
Sunday, January 25, 2009 at 9:41pm by DrBob222

chemstry
when the equation is balanced, the lowest whole number coffinent for hydrogen is?
Wednesday, December 12, 2012 at 10:44pm by los

chemstry
I assume you have an equation in mind. How about letting us in on what it is?
Wednesday, December 12, 2012 at 10:44pm by DrBob222

chemstry
What mass of sucrose must be taken for solution weight of 200 g, which is equal to molality 0.05 mol / kg?
Thursday, November 15, 2012 at 12:37pm by michelle

chemstry
calculate the amount of energy required to convert 55.0g of ice at -10.0c into steam at 125c?
Thursday, November 29, 2012 at 2:32pm by celeste

chemstry
Classify six kinds of amino acids according to the functions that they serve in the human body, stating an example for each class.
Monday, January 21, 2013 at 5:49pm by zachary

Chemstry
4NH3+5O2--->4NO+6H2O determine the amount of oxygen needed to produce 1.2x10^4mol of nitrogen monoxide gas
Tuesday, September 20, 2011 at 10:20pm by Sven

Chemstry
How many moles of NaCL are contained in .2570 L of a 37.5 mM Solution of NaCl?
Sunday, May 1, 2011 at 8:26pm by Jann

chemstry
How many grams of CaCl2 would be dissolved in 1.4 L of a 0.11 M solution of CaCl2?
Tuesday, March 11, 2014 at 10:20pm by yanely

Chemstry
This implies that the double and triple bond are adjacent to eachother, so that would give the N an expanded octet of 10 electrons, but I thought that only happened after P?
Tuesday, November 9, 2010 at 6:56pm by Phil

chemstry
How long will it take 200 mg of carbon-14 to decay to the point where only 75 mg remain if the half-life is 5770 years?
Thursday, October 31, 2013 at 10:14am by jordan

chemstry
How long will it take 200 mg of carbon-14 to decay to the point where only 75 mg remain if the half-life is 5770 years?
Thursday, October 31, 2013 at 1:02pm by jordan

Chemstry
What is the structure of N4O, where the 3 nitrogen bonds have different bond lengths and the N=O bond is a double bond. I just dont get it
Tuesday, November 9, 2010 at 6:56pm by Phil

chemstry
the hiv virus that causes aids destroys the immune system in the body. classify the hiv virus and explain the statement
Tuesday, January 29, 2013 at 9:55am by zachary

chemstry
the most prominent line in the spectrum of an element is 267.2 in what region of the electromagnetic spectrum is this line found
Sunday, March 16, 2014 at 7:36pm by Anonymous

chemstry
q = mass H2O x specific heat H2O x (Tfinal-Tinitial) q/mol = delta H for 2 mols H2O. Divide by 2 for J/mol.
Thursday, June 21, 2012 at 5:40pm by DrBob222

Chemstry
How many moles are there in 20 mg? 0.020 grams/molar mass = moles lovastatin. Now convert moles to molecules remembering that there are 6.022E23 molecules in 1 mole.
Thursday, February 24, 2011 at 10:49pm by DrBob222

Chemstry
A 4.1089 g piece of aluminum wire with a circular cross section is 42.06 cm long and has density of 2.6989 g/cm3. What is the volume of the wire and the cross sectional area of the wire in cm2?
Monday, September 17, 2012 at 8:15pm by anonymous

chemstry
k = 0.693/t1/2 solve for k Then ln(No/N) = kt No = 200 mg N = 75 mg k from above Solve for t = time in years.
Thursday, October 31, 2013 at 1:02pm by DrBob222

Chemstry
Mercury concentration in a polluted lake is 0.0125 micrograms/L. What is the total mass in kilograms of mercury in the lake if the lake is approximately circular witha diameter of 10 miles and an average depth of 50 ft.?
Wednesday, August 31, 2011 at 11:11pm by Gabrielle

Chemstry
A 5.00 gram mixture of CaO and CaCO3 is heated strongly. After heating, the mixture has a mass of 4.00 grams. What % of the original mixture is CaCO3?
Monday, December 13, 2010 at 9:09am by Paul

Chemstry
Lovastatin (C24H36O5) has a molar mass of 404.53 g/m. The normal dose of the drug lovastain is 20mg. How many molecules of lovastatin (C24H36O5) are in a normal dose?
Thursday, February 24, 2011 at 10:49pm by Michelle

Chemstry
Convert 5 mi radius to cm and 50 ft depth to cm, then pi*r^2*h will give you the volume in cc. Then convert cc to L and multiply by 0.0125 to give micrograms Hg in the lake. Convert to kg. Post your work if you get stuck.
Wednesday, August 31, 2011 at 11:11pm by DrBob222

Chemstry
Dry air is bubbled through 25 litres of water at a rate of 15 litres (STP)/min. The air leaving the liquid is saturated with water at 25 degrees celcius and 1.5 atm. How long it will take for all of the water to vaporize.
Sunday, August 5, 2012 at 3:12pm by Simon

chemstry
mols = M x L = ? Then mols = grams/molar mass You know mols and grams, solve for grams.
Tuesday, March 11, 2014 at 10:20pm by DrBob222

CHEMSTRY
. A 25.0 ml sample of Ni2+ gave a weight height of 2.36 uA( corrected for a residual current) in a polarographic analysis. When 0.500 ml of solution containing 28.7 nmol of Ni2+ was added the wave height increased to 3.79 uA. Find the concentration of Ni2+ in the unknown?
Saturday, November 22, 2008 at 12:26pm by ABDULALEH

chemstry
In a constant-pressure calorimeter, 50.0 mL of 0.340 M Ba(OH)2 was added to 50.0 mL of 0.680 M HCl. The reaction caused the temperature of the solution to rise from 23.69 C to 28.32 C. If the solution has the same density and specific heat as water, what is H for this ...
Thursday, June 21, 2012 at 5:40pm by cassie

Chemstry Help Drbob!
How much heat (in kJ}) is required to vaporize it? (Assume a density of 1.00 g/mL ) I have this 60.0ML/ 1.00 g/ml = 60grams 60/153/81 g/mol = .3900916715 moles .3900916715 moles / 43.9 kj/mol = 17.122 And it keeps telling me the answer is wrong.
Sunday, January 25, 2009 at 9:41pm by Creative9k

CHEMSTRY
. A small amount of solid Hg2Cl2 and 25 ml of metallic mercury were added to a solution of 5.03 x 10-2 M NaCl. A platinum electrode immersed in the layer of mercury was connected to a reference half-cell whose electrode potential was 0.222V. The voltage of the cell was 0.121 V...
Saturday, November 22, 2008 at 12:25pm by ABDULALEH

Chemstry
You are correct that the Pb electrode is the anode and that it is negatively charged. The half reaction is correct also, although that doesn't show the next step to form PbSO4 from the Pb^+. Technically, that is not part of the half reaction, though. For the cathode, what you ...
Monday, April 28, 2008 at 8:32pm by DrBob222

Chemstry
The CaO is just an innocent bystander. The loss in mass is due entirely to the amount of CaCO3 present initially. So convert loss of mass (grams CO2) to moles CO2 and convert that to moles CaCO3. Finally moles CaCO3 to grams CaCO3. Then percent CaCO3 = (mass CaCO3/mass sample...
Monday, December 13, 2010 at 9:09am by DrBob222

Chemstry
mass = volume x density You know mass and density; solve for volume of the wire Then volume of wire = pi*r^2*length Solve for pi*r^2 = area
Monday, September 17, 2012 at 8:15pm by DrBob222

chemstry
Two formulas you need. Within a phase: mass x specific heat x (Tfinal-Tinitial). For example: water from zero C to 100 C as a liquid it will be grams H2O x 4.184 x (100-0) = q At a phase change: melting point phase change is q = mass ice x heat fusion. boiling point phase ...
Thursday, November 29, 2012 at 2:32pm by DrBob222

Chemstry
For the reaction A(g) + B(g) <==> C(g) + D(g) the equilibrium constant K is defined as K = Y(sub y) * Y(sub D) / (Y (sub A) * Y(sub b)) where y is the molar fraction of the gas phase of a species At 620.00 K, the equilibrium constant is 1.100. Suppose the feed to a ...
Wednesday, July 11, 2012 at 12:32am by Simon

Chemstry/(microsoft excel)
I am having a hard time solving this problem. The formula given is: T=Tin - (Tin - Tinit.)e(-v/v)t If the initial temperature Tinit is 115 (degrees F), the cold water temperature is 35 (degrees F) (1.7 degrees C), and the volume and volumetric flow rate are 3,000 liters and ...
Monday, September 26, 2011 at 12:01am by Kadeem

chemstry
you want t where 200*2^(-t/5770) = 75 2^(-t/5770) = 75/200 = 0.375 -t/5770 = log(.375)/log(2) t = -5770*log(.375)/log(2) t = 8164 years Makes sense since 1/2 > .375 > 1/4 so in half lives, 1 < t < 2
Thursday, October 31, 2013 at 1:02pm by Steve

Chemstry
http://onlinelibrary.wiley.com/doi/10.1002/anie.199316101/abstract
Tuesday, November 9, 2010 at 6:56pm by DrBob222

Chemstry/(microsoft excel)
You really don't need an excel program to do this. heat lost by warm water (3000L) + heat gained by cool water (30L/min) = 0 Five minutes into the operation you have 3000L of 115 C water(convert to C and call that Tinitial for the hot water.That part of the equation is [mass ...
Monday, September 26, 2011 at 12:01am by DrBob222

chemstry
This is not chemistry but immunology/biology. The HIV virus is what microbiologists/immunologists classify as an RNA virus. RNA viruses are not like DNA viruses because they use their RNA transcript to infect cells, namely helper t-cells. Helper t-cells are a type of white ...
Tuesday, January 29, 2013 at 9:55am by Devron

Chemstry
I just copied this because i have a couple more questions on this part.... Sulfuric acid/ Lead Battery: -the electrodes for the battery are composed of Pb(s), PbO2, and/or PbSO4. What are the half reaction occuring at each electrode? include electrolysis of water: Process ...
Monday, April 28, 2008 at 8:32pm by Sara

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