Thursday
October 2, 2014

Posts by GK


Total # Posts: 640

Chemistry
MgO is 60.3% Mg. Mg3N2 is about 72% Mg Mg3N2 with water added changes to Mg(OH)2 which is then is changed to MgO upon heating. For a small sample, the overall weight changes are quite small. You would need very precise lab results to make accurate calculations of the % of ...
September 23, 2008

CHEMISTRY
Addendum: This is an example of a Hess's Law problem. Your textbook should have some solved examples. Here is one solved example online: http://answers.yahoo.com/question/index?qid=20080514171625AAsqOoC
September 22, 2008

CHEMISTRY
REWRITE the three reactions and their ∆H's (a) Reverse the 1st reaction and change the algebraic sign of its ∆H (b) Leave the 2nd reaction and its ∆H unchanged. (c) Double the 3rd reaction (multiply all its coefficients by 2). Double its ∆H, also. (...
September 22, 2008

Chemistry
(a) First find the transition energy from the frequency by using the Planck equation: deltaE = (6.63x10^-34Js)(frequency) (b) Use the equation below: deltaE = (-2.18x10^-18J)(1/b^2 - 1/a^2) a and b are small integers with b>a Calculate deltaE using trial values for b and a ...
September 21, 2008

chemistry
In the initial first order reaction, rate = k[substrate concentration] As time passes the enzyme becomes bound with substrate into an enzyme-substrate complex. At this point the rate of product formation depends on the rate of decomposition of the complex and independent of ...
September 21, 2008

history/chem
Both, Aristotle and Plato believed that matter could be subdivided indefinitely into smaller and smaller parts. In other words, they did not believe in indivisible units or atoms. Their contribution to chemistry was that they thought about, and discussed the ultimate structure...
September 19, 2008

Chemistry
Consider the following: *When you dissolve NaCl in water, the mixture cools indicating an endothermic change. It leads to products with higher enthalpy. *NaCl crystals are highly orderly structures which means that their entropy is low. As they dissolve in water they ...
September 19, 2008

chemistry
10.8 million gal=1.08x10^7 gal (1.08x10^7 gal)(3.78 dm^3/gal) = 4.08x10^7 dm^3 0.5 mm /100 mm/dm = 0.005 dm V = Ah, where h is the film thickness. 4.08x10^7 dm^3 = A(0.005 dm) (A = area of spill) A = 8.16x10^9 dm^2 1 m^2 = 100 dm^2 A = 8.16x10^7 m^2 1 mile^2 = (1609m)^2= 2....
September 18, 2008

Chemistry
This question has been answered already
September 18, 2008

Chemistry
Is it 1.2 L and 3.0 L ? If so, 1.2 L / 3 breaths = 0.4 L / breath (3.00 L) / (0.4 L / breath) = 7.5 breaths (7.5 breaths)(0.060 mol/breath) = 0.45moles
September 17, 2008

Chemistry
The simplified reaction is: C5H11O5-CHO + 2Cu^2+(aq) —> C5H11O5-COOH + Cu2O(s) + H2O The aldehyde group,-CHO, in the ketohexose (such as glucose, galactose, etc) oxidizes to a carboxyl group, -COOH. That releases electrons which reduce Cu+2 to Cu^+1 (blue cupric ...
September 16, 2008

AP Chemistry
Clarification: In the last step multiply the three numbers in the mole ratio by the same number. Select the smallest multiplier that will give a three whole number ratio. Tose three numbers are your subscripts.
September 16, 2008

AP Chemistry
(a) Convert the grams of CO2 to moles of CO2 by dividing grams of CO2 by the molar mass of CO2. Moles of CO2 = moles of carbon, C. Multiply moles of C by 12.011g/mol to get grams of carbon in the sample. (b) Find the moles of H2O in a similar way. Moles of H = (2)(moles of H2O...
September 16, 2008

Chemistry
Percent error is calculated by dividing the value of the error by the accepted value and then multiplying by 100.
September 16, 2008

chemistry
Name any two elements form the extreme left column of the periodic table.
September 16, 2008

college chemistry
The density of Cu is 8.96 g/cm^3. The density of Pb is 11.4 g/cm^3. Let the mass fraction of copper, Cu = x, Then the mass fraction of Pb is (1-x). The algebraic expression for the "weighted" average density is: 8.96x + 11.4(1-x) = 9.60 Solve for x to get the mass ...
September 15, 2008

chemistry
The atoms and molecules making up any material are in constant motion. The amount of molecular motion depends on the temperature.
September 15, 2008

Chemistry
Correction: (b) If you divide grams by moles you get grams/mole, the molar mass. Comment: No web page makes a good substitute for your chemistry class and your chemistry textbook.
September 15, 2008

Chemistry
(a) Multiply the number of moles by 6.02x10^23 atoms/ mole. (b) If you divide grams by moles you get grams/mole, the atomic mass.
September 15, 2008

physics
The initial vertical component of the velocity is: Vyo = (35.5m/s)(sin49.9) = _____ m/s The vertical distance can be described by: y = (Vyo)t + (1/2)(-9.8m/s^2)t^2 At the time the ball was caught: 0.877m = (Vyo)t + (1/2)(-9.8m/s^2)t^2 Substitute the value for Vyo and rearrange...
September 12, 2008

Chemistry 2 Ap
Same suggestion as the previous one. Divide the grams of CaCO3 but the molar mass of CaCO3.
September 10, 2008

Chemistry 2 Ap
Find the mass of 1 mole of CaCO3. Divide the grams of CaCO3 by its molar mass.
September 10, 2008

physics
Correction to the previous answer: "The height above the ground of the glasses is: 32.0m - (1/2)g(t-2)^2" should read: The height above the ground of the pen is: 32.0m - (1/2)g(t-2)^2
September 10, 2008

physics
Find the time of fall by using: y = (1/2)gt^2 (y is given and g = 9.8m/s^2, Solve for t) When the glasses hit the ground, the pen has been falling for (t-2.00s). The height above the ground of the glasses is: 32.0m - (1/2)g(t-2)^2
September 10, 2008

Chemistry
AgI precipitates first because it has lower Ksp and lower solubility: Ksp =[ Ag+][I-] = 1.5x10^-16 [0.010][I-] = 1.5x10^-16 [I-] = 1.5x10^-14 when AgI begins to precipitate. Ksp = [Cu+][i-] = 5.3x10^-12 for CuI [0.010][I-] = 5.3x10^-12 [I-] = ?___ when CuI begins to ...
September 9, 2008

Physics
(a) accelerating upward with an acceleration of 1.10 m/s2, F(net) = F(up) + F(down) ma = Fup + Fg (74.0kg)(1.10m/s^2) = Fup + (74.0kg)(-9.8m/s^2) Find Fup to get the scale reading (The scale reading is the value of the upward force of the spring inside the scale) (b) moving ...
September 8, 2008

Chemistry
The answer to what question is 200? •If the question is to find the % by mass, then (50.0mL)(1.00g/mL) = 50.0g H2O, and mass% = (100)[10.0g / (10.0g + 50.0g)] = 16.67% •If the question is to find the grams/liter, then [(10.0g)/(50.0mL)](1000mL/L) = 200 g/L •If ...
September 6, 2008

physics
Use Coulomb's Law: F = k*Q1*Q2 / r^2 k = 9.00x10^9 N.m^2/C^2 (Coulomb's constant) Q1 = Q2 = 1.60x10^-19C (Elementary charge) r = given in the question (distance) Note: The charge of a proton is equal to the charge of an electron except for the algebraic sign.
September 5, 2008

AP Chemistry
107.870 + 79.909 = 187.779 %Ag = [(107.870 / 187.779](100) = 57.4452% %Br = [(79.909/187.779)](100) = 42.5548% (13.2160 g AgBr)(0.42.5548) = 5.624g Br in AgBr [(5.624g Br)/(12.5843g ZrBr4)](100) = 44.691% Br in ZrBr4 100.000 - 44.691 = 55.309% Zr in ZrBr4 Let the atomic mass ...
September 5, 2008

Chemistry
The balanced chemical equation is: 2MnO4^-(aq) + 16H^+(aq) + 5C2O4^-2 ---> 2Mn^+2 + 8H2O + 10CO2 46.88mL - 11.23mL = 35.65mL MnO4- solution •Moles of MnO4^- = (0.03565L)(0.201mol/L)
September 4, 2008

Chemistry 2 AP
The chemical equation is: (NH4)2Cr2O7 --> Cr2O3 + N2 + 4H2O •Find the mass of 1 mole of (NH4)2Cr2O7. •Divide 10.8g (NH4)2Cr2O7 by the mass of 1 mole to get the number of moles. •The number of moles of N2 and of Cr2O3 are the same as the number of moles of (...
September 3, 2008

Chemistry
Balancing oxidation-reduction (redox) reaction is a complex process. You must know how to assign some oxidation numbers and how to calculate others no matter which method you use. The best method in my opinion is the “Ion-Electron” method. This is not a lesson on ...
September 3, 2008

Chemistry
Correction: "Be/BeH2 = (1.008)(2)/11.03 = 0.1828 = 18.28% H." should read: 2H/BeH2 = (1.008)(2)/11.03 = 0.1828 = 18.28% H.
September 2, 2008

Chemistry
Hydrogen has the lowest atomic mass. That would make the % of hydrogen in most hydrides very low since the H atoms would be linked to much heavier atoms. The two percents given are actually high indicating that the hydrides are linked to a relatively small atom, possibly from ...
September 2, 2008

Chemistry
•(0.03644L)(0.013 mol/L) = 4.7372x10^-4 mol Fe+3 •(4.7372x10^-4 mol Fe+3)(1 mol H2C2O4 / 2 mol Fe+3) = 2.37x10^-4 mol H2C2O4 •Find the molar mass of H2C2O4 and multiply by the moles of H2C2O4 to get the mass in grams. The mass of H2C2O4 over the mass of the ...
September 1, 2008

Chemistry
I think it was 35 mL of 0.1M AgNO3, not AgCl. When the two solutions are mixed the reaction is: 2AgNO3(aq) + MgCl2(aq) ---> AgCl(s) + Mg(NO3)2(aq) Moles of AgNO3 = (0.035L)(0.1mol/L) = 0.0035 moles of AgNO3. Moles of Ag+ ion = 0.0035 also. Likewise, moles of MgCl2 = (0.015 ...
September 1, 2008

chemistry (buffers)
Buffers are combinations of a weak acid and a weak base, not a weak acid and a strong base.
September 1, 2008

Physics
(a) distance = speed x time or time = distance/speed The two times can be found by dividing the distance by each speed. Subtract the two times. (b) Let t = time it takes the slower student. 5.50 min = 330 s The distance is 0.90t = 1.90(t-330) Solve for t, then substitute into ...
August 31, 2008

chemistry
aspirin (acetylsalicylic acid), vitamin C (ascorbic acid) and vitamin B-12 (folic acid) are acids. Aluminum hydroxide, magnesium hydroxide and calcium carbonate are bases used as stomach antacids. Magnesium citrate (laxative), ferrous sulfate (iron supplement), morphine ...
August 31, 2008

chemistry
Set 1 varies from 1.374 to 1.400, a range of 0.026 Set 2 varies from 1.347 to 1.401, a range of 0.054 Set 3 varies from 1.301 to 1.499, a range of 0.198 The narrower (smaller) the range, the greater the precision. Now you should be able to rank the three sets of results.
August 30, 2008

chemistry
The range from the freezing temperature of water to the boiling point of water is as follows: Fahrenheit: 32 to 212 deg., a range of 180 degrees Celsius: 0 to 100 deg., a range of 100 degrees Kelvin: 273 to 373 deg., a range of 100 degrees So ... if we are talking about ...
August 30, 2008

Chemistry
1. HCl (strong acid completely split into ions) *Find the concentration after dilution using: V1M1 = V2M2 (8.00mL)(0.10 M) = (100.0 mL)(M2) *M2 = (8.00mL)(0.10 M) / (100 mL) = ?______M *pH = -log(M2) 2. HC2H3O2 (weak acid only partially dissociated into ions): *Find the ...
August 20, 2008

Chemistry/pH- Weak Acid
The Rule of 5% may be reasonable but arbitrary. I have not seen it in any textbook I use. If the approximate solution is not satisfactory solve the quadratic equation: Ka = x^2 / (c-x) with he proper values for the Ka and c (the overall acid concentration). That is tedious ...
August 18, 2008

Chemistry/Redox Reactions
1. Find the the standard cell potential of the initial Al-Ni electrochemical cell (before the addition of NaOH). Consult your General Chemistry textbook on how to do this. 2. The solubility equilibrium is: Al(OH)3(s) <=>Al^3+(aq) + 3OH-(aq) Ksp = [Al+3][OH]^3 [OH-](eq...
August 18, 2008

physics/science
If the plastic beads and the plastic beaker were electrically charged with the same kind of charge, how would they interact? I assume the beads are very light. When they were "poured" out of the beaker, What would the electrically charged beaker do to the beads? You ...
August 17, 2008

Chemistry/pH- Weak Acid
Go over the approximate solution solution I gave you in the previous question. You can improve the values you get by substituting and solving the quadratic equation, Ka = x^2 / c - x) The approximate solution is probably adequate. Check the method here: http://Jiskha.com/...
August 17, 2008

Chemistry/pH- Weak Acid
For a pH = 4, [H+] = antilog(-4.000) = 1.00x10^-4 Ka = [H+][A-] / [HA] Let [H+] = [A-] = x Ka = x^2 / (c - x) , where c = molar concentration of HA before dissociation. if c is much larger than x, we can simplify the expression to: Ka = x^2 / c (1.00x10^-6)c = 1.00x10^-8 c = 1...
August 17, 2008

Chemistry/Equilibrium calculations
I noticed I rewrote the Kp as 1x10^-22 instead of 1x10^-13. Sorry. In the comparison of Kp with Qp for the reverse reaction we have: Kp=10^13 > Qp=10^5, leading to the conclusion that CO is still changing to CO2 as it escapes and its concentration decreases as I suggested ...
August 16, 2008

Chemistry/Equilibrium calculations
Comment of my Qp calculation: I assumed that those percents are volume/volume percents. Since in the gas state moles are proportional to volume, and the partial pressure of each gas is proportional to moles, the volume percents were assumed to be proportional to partial ...
August 16, 2008

Chemistry/Equilibrium calculations
2CO2(g) <=> 2CO(g)+ O2(g) Kp = 1 E-13 (or 1.00x10^-22) The LEFT side is favored. It is perfectly proper to write the reaction backwards: 2CO(g)+ O2(g) <=> 2CO2(g) BUT now the Kp is the reciprocal of 1.00x10^-22 or Kp = 1.00x10^22 for the reversed reaction The ...
August 16, 2008

chemistry
Not sure what you mean by "atomic nature". The formula of glucose is C6H12O6 which shows you how many atoms of carbon, hydrogen, and oxygen there are in one molecule of glucose.
August 15, 2008

Chemistry
To find the molarity, 1. Convert the 140 mLs of benzene to liters 2. Molarity = (moles of toluene) / (liters of benzene) NOTE: This is a continuation of the previous answer (finding the molality). Refer to steps 2 and 3.
August 15, 2008

Chemistry
1. Use: mass = (volume)*(density), or grams = (milliliters)(grams/ml) to calculate the mass (grams) of each compound. 2. Find the molar mass of toluene. 3. Divide the mass (grams) of toluene by the molar mass of toluene to convert grams to moles. 4. Convert the grams of ...
August 15, 2008

Chemistry
*Convert 1.750g of Fe(NH4)2(SO4)2•6H2O to moles by dividing by the molar mass of this compound. *Find the moles of H2C2O4 using: moles = (liters)(mol/L) Te moles ratio of the two reagents id 1 to 1. That means that the smaller number of moles belongs to the limiting ...
August 11, 2008

ap chemistry
The topics of the questions you are asking are not covered adequately even in a college General Chemistry textbook. An Organic Chemistry textbook would be more helpful for most of the 13 questions. A good starting point for organic chemistry is the online textbook, General ...
August 11, 2008

Chemistry
A very similar question was posted and answered here: http://Jiskha.com/display.cgi?id=1218235719 Check it out for the method used. It is the same as your question. Only the numbers are slightly different.
August 10, 2008

chemistry
Naming an organic compound or writing its name is not something you learn in one easy lesson. There are so many groups and so many rules. You need a course in organic chemistry just to get started. AP Chemistry and General Chemistry in college cover this very lightly. Here are...
August 9, 2008

chemistry
A condensed formula shows the functional groups in a molecule and any double or triple bonds, usually, on a single line. Here you have a a 4-carbon chain with a double bond between the 2nd and 3rd carbon. Also, methyl groups on carbons #2 and #3: CH3C(CH3)=C(CH3)CH3 Sometimes ...
August 9, 2008

chemistry
Convert 2.13 g TlOH to moles. Divide moles by 1 liter to get the molar concentration in moles/liter or "M". moles/L of TlOH = moles/L of OH- ions (since TlOH is a strong base). Calculate the pOH: pOH = -log[OH-] and pH = 14 - pOH
August 8, 2008

Chemistry
I looked up two half reactions form a "Standard Reduction Potentials" table. The 2nd half reaction occurred in reverse as an oxidation. I doubled this reaction so that the number of electrons gained and lost are equal. Then I combined the two half reactions into an ...
August 8, 2008

Chemistry
A comprehensive look at this equilibrium system and the experiment for determining the equilibrium constant is given here: http://www.scienceteacherprogram.org/chemistry/Tehilla98.html
August 8, 2008

Chemistry
The concentration of SCN- in the first mixture is: (1/10)(0.0020M) = 0.0020M) The concentration of Fe+3 was: (9/10)(0.200M) = 0.18 M Since the concentration of F+3 was 90 times the concentration of SCN-, we may assume the equilibrium, Fe+3(aq) + SCN-(aq) <=> FeSCN+2(aq...
August 8, 2008

physics
Do you need a numerical answer? If the bat is flying towards the wall, f' = f*[V+Vs) / V] f' = unknown, f = 35 kHz, V = 343 m/s (in dry air, 20 deg C), Vs = (5.0*2 = 10 m/s) <--Based on drwls</> suggestion, the source moves with a velocity of 5.0 m/s toward ...
August 4, 2008

physics
Let the initial velocity = Vo The horizontal comonent, Vx = Vo(cos23) The horizontal distance, x = Vo(cos23)t = 8.7m t = 8.7m / Vo(cos23) The vertical component of initial velocity is Vyo: Vyo = Vo(sin23) Let the final vertical velocity be Vyf. Then, Vyf = 0 (a the highest ...
July 31, 2008

chemistry
Not sure if you are asking about a molecule or an ion. The only structure I could come up with that would obey the octet rule using 60 valence electrons was: Cl-O3-P-P-O3-Cl The two P's linked to each other. Each P attached to 3 O's. Each Cl linked to an O. The total ...
July 30, 2008

organic chemistry
Do a Google image search on "morphine isomers". Look at the best structure you can find. Locate the central carbon atoms that are linked to four different "groups". The four "groups" could be four carbon atoms which are linked to different parts ...
July 26, 2008

o chemistry
Represent C #2 with a dot and C #3 with a concentric circle around the dot. C #2 (the dot) has two bonds coming out of it, one leading to a methyl, CH3 and another leading a Cl. C #3 (the circle) also has two bonds coming out of it, one leading to a methyl, CH3 and another ...
July 26, 2008

Analytical Chemistry
The low pH is needed to prevent the Fe^+3(aq) indicator from hydrolyzing (forming hydroxy complexes and eventually iron(III) hydroxide). If the ferric salt indicator is altered, there is no clear end point during the titration.
July 25, 2008

chem 3A
I am giving outlines below for solving problems #1 and #2. The others involve the same or similar principles. The general topic is reaction stoichiometry. It is hard to cover such a broad topic adequately through postings here. Question #1 (a) Use the Ideal Gas Law to find ...
July 25, 2008

Chem 3A
The balanced chemical equation assumes a theoretical yield of 100%. To calculate the actual yield we must know the amounts of reactants (Mg and HCl) actually used.
July 25, 2008

Chem 3A
Metal + acid ---> metal salt + hydrogen gas Mg + HCl --> MgCl2 + H2 If you place the correct coefficient in front of HCl, you will have the chemical equation balanced for Cl and H (which it is not now).
July 25, 2008

Organic Chemistry
Another argument I just overlooked is that one of the reactants, cinnamaldehyde, contains a trans structure around the c=c double bond that is preserved in the final compound, 1,4-Diphenyl-1,3-butadiene. Thus, we cannot have two cis structures in the C=C-C=C chain which is the...
July 24, 2008

Organic Chemistry
It is most likely cis,cis-1,4-dephenyl-1,3-butadiene. If you draw it you would see a U-shaped molecule with the two phenyl groups getting close together at the the ends of the "U". Formation of this isomer is probably prevented by crowding (steric hindrance) at the ...
July 24, 2008

Chemistry
The moles of each reactant are: (8.8g of Mg) / (24.3gMg/moleMg) = 0.362 moles Mg 21.0g N2 / 28.01 g/mol N2 = 0.750 mol N2 The mole ratio of Mg to N2 in the chemical equation is 3/1 The mole ratio in the mixture is 0.362 mol Mg / 0.750 mol N2 or 0.483 mol Mg / 1 mol N2 ( a LOT ...
July 24, 2008

physics
100 km/h = 100000m/3600s = 27.8 m/s Vf^2 = Vi^2+2as The final velocity, Vf, is 0 0 = (27.8m/s)^2 + (2)(55m)(a) Solve for the acceleration, a. F = ma Use the acceleration from the previous step and the mass given to get the force, F.
July 22, 2008

Chemistry
I think the problem was constructed with the false assumption that the yield is independent of concentration and I accepted it uncritically. Le Chatelier's Principle still rules. Glad you were so alert. I checked [A]=[B]=3M with my setup and got a 75% yield, farther to the...
July 22, 2008

Chemistry
Since the answer I got is a bit different from the one given, here is my complete take on this: Assume 1 mole of A and 1 mole of B reacting (This is legitimate since the yield should be independent of the actual number of moles used as long as they are equal). Let's ...
July 22, 2008

physics
Yours (Damon's) is a more elegant solution than mine, since you are using a more general formula for vertical motion and correct algebraic signs. I assume the relationship used is: Y = Yo + (1/2)gt^2, using the values you assigned. The zero point is the bottom of the cliff...
July 21, 2008

physics
The equation is: 50 m = (1/2)(9.8m/s^2)(t^2) (It is less confusing to use absolute values here-No negative signs) t = sqrt[(2*50m)/(9.8m/s^2)] = sqrt(10.2s^2) (t = much shorter than 40.2 s)
July 21, 2008

Organic Chemistry
Camphor has a carbonyl group which would produce an IR band at 1750 cm^-1. During the reduction, the C=O group would change to C-OH which absorbs IR at a much higher spatial frequency. The reduction might have been incomplete, with enough camphor present to produce the 1750 cm...
July 21, 2008

Chemistry
Use the Ideal Gas Law: PV = nRT Substitute: P = 0.973 atm V = Unknown. Solve for this variable. n = 0.01mol CO R = 0.0821 L.atm/K.mol [a constant] T = 9 + 273 = 282 K
July 21, 2008

physics
The combined resistance of resistors connected in series is the sum of their resistances. Just add the three resistances.
July 20, 2008

physics
Coulomb's Law is: F = kQ1*Q2 / d^2 k is a constant Let's represent each charge as "q" then the intial force F1 is: F1 = k*q*q / 1^2 = kq^2 doubling the charge, the new force, F2, is: F2 = k(2q)(2q) / 1^2 = 4kq^2 F2 is how many times bigger than F1?
July 20, 2008

physics
1 Pa = 1 N/m^2 [I think you meant 105kPa = 105000Pa] (1.8)(105000Pa) = 189000 Pa = 189000 N/m^2 Total area of contact = (0.025 m2)(4) = 0.100 m^2 If you multiply the total pressure by the area of contact you will get the total weight in newtons. Note: If you divide the weight ...
July 20, 2008

physics
Convert km/h to m/s: (90 km/h)(1000m/1km)(1 h/3600s) = 25.000 m/s (75 km/h)(1000m/1km)(1 h/3600s) = 20.833 m/s Let time of catching up = t The distance travelled by slower car = (20.833 m/s)(t) The distance travelled by faster car = (25.000 m/s)(t) The distance travelled by ...
July 20, 2008

physics
Let "omega" = w = angular velocity 1 rev/s = 2pi rad/s angular velocity = w = (0.400)(2pi rad/s) = 2.5133 rad/s Linear velocity = v = wr v = (2.5133 rad/s)(1.5m/rad) = 3.77 m/s Linear accel. = (change in velocity)/time = a a = (Vf - Vi)/t = (3.77 m/s - 0)/2.00 s = ...
July 20, 2008

organic chemistry
One bromine atom becomes attached to the first carbon in the first stage of the reaction. The 2nd carbon becomes positive and bond with a water molecule which then loses a proton to form a hydroxyl group. H2C=CHCH2CH2CH3 + Br2 --> BrH2C-CH(+)CH2CH2CH3 + Br- BrH2C-CH(+)...
July 19, 2008

Organic chemistry
We would use a Friedel-Crafts alkylation of benzene: Benzene + 1-chloropropane ---> Propylbenzene + HCl. The catalyst used is AlCl3
July 18, 2008

chemistry
The procedure suggested by DrBob 222 will give the correct answer to the question. However, the wording of the question itself could be improved. It might be: "Calculate the total volume of solution (water + CaCl2) when a 0.0250 M CaCl2 solution is prepared by dissolving ...
July 15, 2008

organic chemistry
Acetic acid can be neutralized with sodium bicarbonate. The products of neutralization are H2O, CO2, and sodium acetate, NaC2H3O2. Carbon dioxide,CO2, escapes as a gas. Sodium acetate dissolves in water. So, the excess of acetic acid is first converted to other compounds that ...
July 14, 2008

chemistry
Do a Google search using as your search phrase: partial molar enthalpy of solutions. The very first result will be a PDF file that will addresses your topic. I hope you are familiar with partial derivatives and the laws of thermodynamics sufficiently to understand this file. ...
July 13, 2008

Chemistry
It is great working with you again DrBob. I answered this same question on another network that allows links. The student was kind enough to provide a link to the procedure with a diagram, otherwise I would not have been able to visualize the experiment. My usual approach is ...
July 11, 2008

Chemistry
Comment: Lab questions are difficult to judge because we do not know what the instructions were, how close they were followed, and what assumptions can be made in answering the post-lab questions. Here is my take on the questions on the determination of the Gas Constant, R. I...
July 11, 2008

Organic Chemistry
The major product is 1-cyclohexenol or 1-hydroxycyclohexene. The tautomeric form is cyclohexanone.
July 10, 2008

Chemistry
Thank you, DrBob. JenniferT deserved a correct answer.
July 10, 2008

Chemistry
Since the solutions are 1.0M, E(cell) equals the difference of the standard reduction potentials. In more complicated cases (molar concentrations not equal to 1.0M) you would have to use the Nernst Equation.
July 10, 2008

Chemistry
This question has already been posted and answered, but I have a comment on the last part. The reason the spectral color lines are different for each element is that the photons produced by the dropping of electrons to lower energy levels within an atom are different for each ...
July 10, 2008

Chemistry
1. A flame heats the sample and may produce a flame color that helps us detect the presence of a certain element. Some elements cause the flame to glow a certain color which tells us that element is present in the sample. For example, a very bright yellow-orange flame color ...
July 10, 2008

Chemistry
1. The weight loss from 45.850g to 45.351g is the mass of oxygen, O2, gas released. The molar mass of O2 is 16.00x2 = 32.00g. This information should enable you get the moles of O2. 2. The volume of O2 = volume of water displaced. volume = mass/density. The density of water is...
July 9, 2008

physics
Electrical potential is the force experienced by a unit test charge at a particular point. In this case that potential on the test charge is generated by the positive and the negative charges placed in the two corners of the square. There are two possible configurations for ...
July 8, 2008

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