Sunday
August 31, 2014

Posts by GK


Total # Posts: 640

Biochemistry
Add water and mix. One of them will dissolve in the water. The other will not.
December 1, 2008

chemistry
The overall reaction is: Mn(s) + Cd^2+(aq) --> Mn^2+(aq) + Cd(s) (Mn is higher on the activity series than Cd) Eo(cell) = Eo(Cd)- Eo(Mn) with 1M solutions at 298K Eo(cell) = -40v - (-1.18v) = 0.78v With the given concentrations, E(cell) = Eo(cell) - (0.059/n)(logQ), where Q...
November 30, 2008

Chemistry
1. The product is an addition compound in which the =O becomes OH and the central carbon atom is linked to the sulfite group. No special IUPAC name as far as I know. 2. The products are the 2,4-dinitrophenylhydrazone of propanone or 2,4-dinitrophenylhydrazone of ethanal. The ...
November 30, 2008

Chemistry
Osmotic pressure is given by: π = MRT π = osmotic pressure in atm Mi = moles of particles/liter <- unknown R = 0.0821 L.atm/K.mol T = 298 K • Substitute and solve for Mi to moles of ions per liter. • Divide Mi by 3 to get the overall molarity, M, in ...
November 29, 2008

Chemistry
Osmotic pressure is given by: π = MRT π = osmotic pressure in atm Mi = moles of particles/liter <- unknown R = 0.0821 L.atm/K.mol T = 298 K • Substitute and solve for Mi to moles of ions per liter. • Divide M by 3 to get the overall molarity, M, in terms...
November 29, 2008

Chemistry
Triglycerides (oils and fats) do not dissolve in water but glucose does. That should suggest a method for separating the two materials.
November 29, 2008

AP Chemistry
The total heat released from steam to liquid, and then ice was: 1.5 + 114 + 21 + 17 = 153.5 kJ That is less than the total heat released of 156 kJ. That is more than enough evidence to confirm (or not) your suggestion.
November 28, 2008

AP Chemistry
The following calculations must be done: (a) Cool the steam to 100 deg C (2.0 J/g.°C)(50.4g)(115°C-100°C) =1512 J = 1.5 kJ (b) Condense the steam at 100 deg C 40700J/mol ÷ 18g/mol = 2261 J/g (50.4g)(2261J/g) =114000 J = 114 kJ (c) Cool the water to 0 deg C (...
November 28, 2008

Dr bob please! Chemistry
Use the Clausius-Clapeyron Equation to calculate the vapor pressure at 325°C. That is the pressure that must be applied to condense the steam at 325°C. Ln(P2/P1) = (∆H/R)[(T2-T1)/T2T1] P1 = 1 atm ∆H = 40700J R = 8.3145 J/°K.mol T2 = (325+273) = 598°...
November 28, 2008

Chemistry
Referring to Part (b) ••Assume [PV] is a state function: PV = (5 L)(2 atm) = 10 L.atm PV = (10L)(1 atm) = 10 L.atm ∆(PV) = [PV]2 - [PV]1 = 10L.atm - 10L.atm = 0 work (not true) ••Actual work = -P∆V which could not be equal to 0 since P is not 0...
November 28, 2008

chemistry
The article below in Wikipedia explains the H/D exchange as it relates to amide links in peptides. The NMR spectrum helps you locate those amide H's which can be easily replaced by the deuterium atoms in D2O. http://en.wikipedia.org/wiki/Hydrogen-deuterium_exchange
November 26, 2008

Biochemistry
Anhydrous Na2SO4 does not react with CH2Cl2. It simply removes traces of water from the solvent, CH2Cl2, by forming a hydrate of Na2SO4 which settles to the bottom. Moisture in the dichloroethylene solvent could contaminate the caffeine residue after the solvent evaporates.
November 26, 2008

chemistry
The first link improved: http://hyperphysics.phy-astr.gsu.edu/hbase/mod6.html
November 23, 2008

chemistry
A couple of links for the particle nature of light that are relatively easy to follow: (Broken Link Removed) http://www.colorado.edu/physics/2000/quantumzone/photoelectric.html
November 23, 2008

chemistry
Wave nature: If we analyze a beam of light with a double slit or a diffraction grating, we get an interference pattern (colored light fringes) which is consistent with the wave nature of light. We can perform measurements on the interference pattern and calculate wavelengths. ...
November 23, 2008

chemistry
Ask your teacher or instructor for a chemistry supplies catalog. The catalog will give you the prices. If you are using salicylic acid and acetic anhydride as the reactants, it would be far more convenient to use an excess of acetic anhydride, a liquid, since the unreacted ...
November 21, 2008

Chemistry. Percent mass...
•0.471g / 303.26g/mol = 1.553x10^-3 mol PbSO4 • moles of Na2SO4 = 1.553x10^-3 —> 0.2206 g (total in the sample) • moles of Pb(NO3)2 reacting = 1.553x10^-3 —> 0.51435g • 1.009 g - 0.2206 g = 0.7884 g Pb(NO3)2 total in the sample • % ...
November 21, 2008

11th grade chemistry
Not sure what you are asking. Strontium iodide, SrI2, is made of Sr^+2, strontium ions, and I^-, iodide ions.
November 20, 2008

Chemistry
(0.4734 dm^3)(0.5000 mol/dm^3) = ____moles Ag+ Moles Cl- = moles Ag+ Grams of Cl- = (35.453 g/mol)(moles Cl-) Grams of metal, M, = 1500g - grams Cl- From the grams of M and grams of Cl- find the % composition of the sample. Find the % composition of some chlorides: FeCl2, ...
November 20, 2008

Chemistry
Is the rate 1.7*10^-3 mol. H2O2/s or 1.7*10^-3 mol. O2/s ?? It makes a difference. Multiply the rate by 60 s to get moles of H2O2 or O2 formed. If the rate is moles H2O2/s, you must divide the moles you get by 2 to get moles of O2. Next, use the Ideal Gas Law, PV = nRT, to get...
November 20, 2008

Physics
The derivation of the simple pendulum formula for the period of oscillation is given in many physics textbooks, and possibly your own. Here is one derivation online: http://dev.physicslab.org/Document.aspx?doctype=3&filename=OscillatoryMotion_PendulumSHM.xml
November 17, 2008

Physics 12
Fg = (1.3kg)(9.8N/kg) = 12.74N Fg can be resolved into two foces, T along the extension of the string, and Fp, at right angles to it. Fp = (12.74N)(cos62)=________N, or Fp = (12.74N)(sin28) =________N The vector triangle I hope you drew, shows the weight, Fg resolved into two ...
November 17, 2008

Chemistry
Before a compound precipitates, the solution must become saturated with it. If the concentration of this compound is below saturation because one of the solutions mixed is too dilute (such as contaminated distilled water), no precipitate forms.
November 16, 2008

chemistry URGENT (2)
Your answer is correct. If a reaction forms a gas, that gas expands into the surroundings and work is done.
November 16, 2008

chemistry URGENT (1)
(26.4mL)(1.00g/mL) = 26.4g H2O To raise the temperature of 26.4 g H2O by (16.4 C- 10.0 C), we need: (4.18 J/g.C)(26.4 g)(6.4 C) = 706 J needed - 82.8 kJ.mol-1 CaCl2 is equivalent to: 82800 J / 111g CaCl2 = 746 J/g CaCl2 released. Use the values: 706 J needed and 746 J/g CaCl2 ...
November 16, 2008

Chemistry
The reactions are: 2C2H2(g) + 5O2(g) —> 4CO2(g) + 2H2O(L) CH4 + 2O2 —> CO2(g) + 2H2O(L) Let moles of C2H2 = 2x, moles CH4 = y. Then, 2xC2H2(g) + 5xO2(g) —> 4xCO2(g) + 2xH2O(L) yCH4 + 2yO2 —> yCO2(g) + 2yH2O(L) Original moles of gas (C2H2 + CH4...
November 16, 2008

Chemistry
2-bromo-2-methybutane reacts with AgNO3 to form AgBr precipitate. If NaI is present, it also reacts reacts with AgNO3 to form AgI precipitate. When you observe the precipitate, how would you know what caused it?
November 16, 2008

Chemistry
work = ∆q - ∆(PV) ∆q = 0 (isothermal process) - ∆(PV) = -[P∆V + V∆P] P∆V = 0 since V = constant work = - V∆P ∆P = (2 atm -1 atm) = 1 atm ∆P = 101.325 kPa work = -(1 dm^3)(101.325 kPa) work = 101.325J
November 16, 2008

Physics
1. The weight of the partner is: F = mg = (66.4 kg)(9.8 N/kg) 2. The work done in a single lift is: work = F x distance lifted. 3. Total work = (work /lift)(27 lifts)
November 15, 2008

physics
Law of Gravitation: F = GM1M2/r^2 Let the first distance = (5r) then, F1 = GM1M2/(5r)^2 or F1= GM1M2/25r^2 The second distance is 1/5 of 5r = r and Let F2 = GM1M2/r^2 (with distance = r) What is the ratio of F2 to F1, or F2/F1 = ? (divide the expression for F2 by the ...
November 14, 2008

Chemistry
n = PV/RT You do not know the volumes of the tires except that they are all the same. "V = 1" (an arbitrary unit of volume) cannot give you a specific number of moles or number of molecules. However how do the numbers of molecules for each gas compare to each other?
November 12, 2008

Dr. Bob, one more thing- Chemistry
Dr. Bob's answer is very thorough. Two more cents' worth from an old chemistry teacher. I have been telling my students that electronegativity differences are very useful in comparing the polarity of covalent bonds. They are not very useful in distinguishing between ...
November 11, 2008

Organic Chemistry
I think you get 1-methyl-2-chlorocyclohexane. Benzoyl peroxide is acting as catalyst.
November 11, 2008

chemistry
The molar mass of Na is 22.99g The density of solid sodium is 0.97g/cm^3 (22.99g/mol) / (0.97g/cm^3) = _____________ What are the units of the above value?
November 9, 2008

chemistry
I doubt this conversion can be done in a single step. Here is a three-step procedure which might work. If one of the other tutors has a better idea, I am sure it would be welcome: Reduce the nitrobenzene to aniline with Fe/HCl, then treat the aniline with H2SO4/HNO2 to get the...
November 8, 2008

chemistry
The magnesium bromide group on the #2 carbon of the butyl chain is replaced by a -CH2OH. The longest chain on this product has 4 carbon atoms.
November 8, 2008

chemistry
In my previous answer I meant that butyl bromide not butyl chloride, reacting with sodium methoxide would produce the ether 1-methoxybutane, or methylbuthyl ether. The reagent, butyl bromide is also called 1-bromobutane in the IUPAC system of naming organic compounds.
November 8, 2008

chemistry
Butyl chloride and sodium methoxide (find them) is your best bet.
November 8, 2008

College Chemistry
Parts Per Million (ppm) are equivalent to milligrams/liter = mg/L. The % of Fe in Fe(NH4)2(SO4)2 6H2O is: (100)(55.845 g)/(392.14g) = 14.24% •Find 14.24% of 0.1405g of the iron containing sample to get the grams of Fe in it. •Convert the grams of Fe to milligrams. &#...
November 5, 2008

Chemistry- DRBOB!! PLEASE?
Molecular orbitals are orbitals for shared electron pairs (also called covalent bonds). They are based on Quantum Mechanics and they have been developed fully for only for diatomic molecules through the second row of the periodic table. There are two kinds of orbitals: Bonding...
November 4, 2008

Chemistry
To oxidize cyclohexene, we use an inorganic reagent such as potassium permanganate which dissolves in water but not in cyclohexene (an organic liquid). A mixed solvent, such as ethanol and water, helps create a single phase so that the two reagents, cyclohexene and ...
November 4, 2008

Chemistry
Dalton's Atomic Theory was based on experimental evidence which lead to the laws of definite and multiple proportions. You may want to research that and other experimental evidence that supports the atomic theory. You will find a lot more about the development of the ...
November 4, 2008

chemistry
The strong nuclear force holds the nucleus together. Neutrons increase the effectiveness of the strong nuclear force in winning over the tendency of the electromagnetic repulsions of blowing the nucleus apart. A more detailed explanation would include quarks, neutrinos, the ...
November 4, 2008

physics oscillator energy
Use: Ep = (1/2)kx^2 to get the elastic potential.
November 3, 2008

Physics SHM
The answer is "yes". If you gave us the complete question we might have been able to offer more suggestions. If the amplitude is used to get something else, you may want to look at this web page: http://hyperphysics.phy-astr.gsu.edu/hbase/pendl.html
November 3, 2008

chemistry
1 mole of C6H5COOH = 122.1234 g (3227kJ/mol)/(122.1234g/mol) = 26.4241 kJ/g Multiply that by the mass of the sample given. Divide the answer by 2.345 C or K to get the number of kJ per degree (the calorimeter constant).
November 2, 2008

Organic Chemistry
Benzyl chloride is an alkyl (not aromatic) halide. The electron density around the halogen is not delocalized effectively. That makes it easier for the halogen to leave as an anion and form silver or some other halide. Bromobenzene has lower electron density because of ...
November 2, 2008

PHYSICS
Vf^2 = Vo^2 + 2ad 0 = Vo^2 + 2ad Vo^2 = -2ad At 60 mph: V^2 = -2ad => a = -V^2/2d a = (60.0 mi/h)^2 / (2)(0.0231mi) a = -77901.64 mi/h^2 1 mi/h^2 = 3600 mi/(h*s) (why?) 1 mi/(h*s) = 1609m/(3600s)(1s) = 0.447 m/s^2 a = -21.64 mi/h/s = -9.67 m/s^2 You calculate the ...
November 1, 2008

Chemistry
You are not giving us enough information to answer your question. Speculating a bit, if you are supposed to use a standard NaOH solution is the buret, and an acid solution of unknown concentration in the flask with phenolphthalein indicator, could you have reversed where you ...
October 29, 2008

chemistry
(a) Bonds on the left side break by absorbing (+) energy and bonds on the right side form releasing (-) energy. Look up the bond energies and set up: ∆Hrxn = E(H-H) + E(C=C) + 4E(C-H) - E(C-C) - 6(C-H). Look up and combine six positive energies on the left with seven ...
October 27, 2008

Chemistry
Correction of one more typo: [H+] = [A-] = [HA] should change to: [H+] = [A-] =3.31x10^-3 M
October 27, 2008

Chemistry
The titration helps determine the molar concentration of HA: Moles of HA(aq) = moles of OH- used moles of OH- = (0.1500Mmol./L)(0.02500L) = 4.050x10^-3 = mol. HA 4.050x10^-3 mol. HA / 0.02500L = 0.162 M HA Next we find the H+ ion concentration [H+] = 10^-pH = 10^-2.48 = 3....
October 27, 2008

Chemistry
According to Raoult's Law, Psolution = XsolventPsolvent 18.6mmHg = X(H2O)*P(H2O at 25o) Look up the water vapor pressure at 25, substitute above, and solve for X(H2O).
October 27, 2008

Chemistry
----------------- DrBob gave you a very good outline for solving this. I will give you a more detailed procedure without the final answer. I had already typed this offline several hours ago. I had to log off in hurry and did not transfer it here at the time...
October 26, 2008

chemistry
Ionization is the removal of an electron from an atom. Nonmetals have higher ionization energies than metals since it is harder to remove an electron from a nonmetallic atom. When you compare elements on the same row (period) of the periodic table, the one farther to the right...
October 26, 2008

College Chemistry
The indicator does not work well in an acid medium. NaHCO3 is used as a buffer to maintain an alkaline pH of about 9. For more information, see the link below: http://www.cforyourself.com/Overview/Primer/Chemistry/c_tests.html
October 25, 2008

physics
I do not believe the question can be answered with a specific value. Here are my reasons: H = gt^2/2 t = sqrt[2H/g] Let the time for 5H = t' 5H = gt'^2/2 t' = sqrt[10H/g] = sqrt(5)*sqrt[2H/g] The ratio of the two times is: t'/t = sqrt(5)*sqrt[2H/g] / sqrt[2H/g...
October 22, 2008

Chemistry
Your first answer is correct.
October 22, 2008

Chemistry Help Please
One more comment: The final answer assumes that: moles of ClO-(aq) = moles of NaClO Based on that, convert the number of moles to grams of NaClO by multiplying the number of moles by the formula mass of NaClO. That would give you the grams of NaClO per 0.5 mL of bleach ...
October 22, 2008

Chemistry Help Please
Correction with apologies. The corrected mole ratio is in bold print: Moles if I2 based on Equation #2: Moles I2 = (1/2)(__moles S203^2-)
October 22, 2008

Chemistry Help Please
Reaction #1 (properly balanced): 2ClO-(aq) + 4H+(aq) + 6I-(aq) –> 3I2 + 2Cl-(aq) + 2H2O Reaction #2 (properly balanced): 2S203^2-(aq) + I2 ---- > 2I-(aq) + S4O6^2- (aq) Moles of S203^2- = (molarity)(volume): (0.032400 mol/L)(__liters S203^2-) = __moles S203^2- Moles...
October 22, 2008

chemistry
The -C-C-C- bond angles in cyclobutane are 144 degrees. In cyclopropane they are 60 degrees. The usual carbon to carbon bond angles in a tetrahedral structure is about 109 degrees. In which compound are the bond angles more strained? That is the LESS stable compound.
October 20, 2008

college chemistry!! need help now!!
Your question has already been answered here: http://Jiskha.com/display.cgi?id=1224463048 The moles of a gas in a mixture, in this case water vapor,depends on the partial pressure of that gas independently of any other gases present. That comes out of Dalton's Law of ...
October 19, 2008

college Chemistry
The volume of air inhaled in 1 hour is (60 min/hr)(15 br./min) = 900 breaths (900 br.)(0.500L/breath) = 450 L To find moles of H2O, use the Ideal Gas Law: PV = nRT 1 atm = 760 mm Hg 47.1mmHg/760 mmHg/atm = 0.061974 atm P = 0.061974 atm for water vapor R = 0.08206 L.atm/K.mol T...
October 19, 2008

Chemistry!
Yes
October 19, 2008

chemistry
(1.384 kg)(5.4 m^2) = 7.5 kg.m^2 The unit is kg•m^2. As far as I know, this unit has no special meaning.
October 19, 2008

Chemistry
1. Convert 20.8 g CaCl2 to moles (Diveide by the formula mass of CaCl2). 2. The heat given off is: ∆H(sln) = (1258 J/°C)(37.1°C - 25.0°C) 3. Divide the answer in step #2 by the answer in #1 to get the joules/mole. This value is negative since the heat is ...
October 18, 2008

Chemistry
1. Convert 3.76 g HC2H3O2 to moles. 2. Divide 54.6 kJ by the number of moles. Attach a negative sign to the answer. The answer is in kJ/mole
October 18, 2008

Chemistry
Step reactions Given: H2O2(l) –> H2O(l) + 1/2 O2(g) ∆H = -98.0 kJ 2 H2(g) + O2(g) –> 2 H2O(l) ∆H = -571.6 kJ Reverse the first reaction and change the sign of the ∆H. Divide all the coefficients of the 2nd reaction and the ∆H by 2: H2O(l...
October 18, 2008

chemistry math
ln(M/Mo) = -kt ln = natural log M = mass left (not needed) Mo = original mass (not needed) (M/Mo) = 0.809 k = 0.693/T(half) T(half) = 5.73X10^3 years.
October 15, 2008

chemistry math
ln(M/Mo) = -kt ln = natural log M = mass left (not needed) Mo = original mass (not needed) (M/Mo) = 0.809 k = 0.693/T(half) T(half) = 5.73X10^3 years.
October 15, 2008

chemistry math
ln(M/Mo) = -kt ln = natural log M = mass left (not needed) Mo = original mass (not needed) (M/Mo) = 0.809 k = 0.693/T(half) T(half) = 5.73X10^3 years.
October 15, 2008

Chemistry
This question has already been posted and answered
October 14, 2008

Chemistry
1. Convert 2.90x10^5kg of (NH4)2SO4 to kilogram•moles by dividing by 132.26 kg/kg.mol 2. Since 2 kg.moles of NH3 produces 1 kg.mole of (NH4)2SO4, multiply the answer to Step 1 by 2 to get kg.moles of NH3 needed. 3. multiply the previous answer by 17.09 kg/kg.mol of NH3 ...
October 14, 2008

college chemistry
Convert 5.80 L O2 to moles. (1 mole of O2 at STP = 22.4 L) Since 2 moles Mg combine with 1 mole O2, moles of Mg = (2)(moles O2) Grams Mg = (moles Mg)(24.3 g Mg/mol Mg)
October 14, 2008

CHemistry Help pleaseee
The balanced chemical reaction is: 2C2H2 + 5O2 --> 4CO2 + 2H2O The mole ratio of C2H2 to O2 is 2 : 5. Rearranging the Ideal Gas Law, we get: n = PV / RT or Let n1 = P1V1/RT (moles of C2H2) and n2 = P2V2/RT (moles of O2 n1/n2 = P1V1/RT * RT/P2V2 Simplifying, n1/n2 = P1V1 / ...
October 13, 2008

Chemistry
Al2(SO4)3 + 3ZnCl2 ---> 2AlCl3 + ?___ZnSO4
October 13, 2008

Chemistry
Ca(OH)2 + (NH4)2SO4 --> CaSO4+ 2NH3 + ?___H2O
October 13, 2008

Chemistry
Convert the mass of dry residue, CoCl2, to moles by dividing it by the formula mass of CoCl2. Determine the mass of water (loss in mass of sample). Convert grams of H2O to moles by dividing by its formula mass. Determine the mole ratio of H2O/CoCl2: (moles H2O) / moles (CoCl2...
October 12, 2008

Chemistry
The balanced chemical equations are: H2O2(aq) + 2H+(aq) + 2I-(aq) ---> 2H20(l) + I2 2S2032- + I2 ---> S4062-(aq) + 2I-(aq) Moles of S2O3^2- = (0.01240L)(0.1025 mol/L) = 0.001271 S2O3^2- Since 1 mole of I2 reacts with 2 moles of S2O3^2-, (0.5)(0.001271mol S2O3^2-) = 0....
October 12, 2008

chemistry
If you look up the heat of vaporization per gram (Joul/g): 1. Change 1.5 moles of water to grams (multiply by 18.015 g/mol). 2. (grams)(joules/gram) ---> joules 3. joules / (joules/s) ---> seconds If you look up the molar heat of vaporization of water (joules/mol): 1. (...
October 11, 2008

physics
If you draw this properly you will observe that along the Fred-Ed line you have a resultant of 6N toward Ed. Along the Ted-Ned line you have a resultant of 4N toward Ned. If you combine the two new vectors graphically, you have a right triangle with the hypotenuse being the ...
October 8, 2008

college - physics
Oops, I did not take the length of the plane into account. My first solution shrank the plane to a point concentrated at the end of its tail. I think this can be fixed by changing the distance, d, from 25m to (25+59.7) m.
October 5, 2008

college - physics
vf2 = vi2 + 2ad (45m/s)2 = vi2 + 2(-5.7m/s^)(25m) Solve for Vi Find the average velocity = (vi+vf)/2 Divide the width of the intersection by vavg
October 5, 2008

Chemistry
If electrons are added to the left side of the half reaction, it is a reduction. In the reaction you are referring to, ClO3- is reduced and As2S3 is oxidized.
October 4, 2008

chemistry
Two statements are correct, one is wrong, and one is probably correct in the context it is asked. Noble gas atoms have higher ionization energies than halogens. Those nonmetals that form stable anions release energy as they do so.
October 4, 2008

Chemistry
A. The dissociation of Zn2Fe(CN)6 is: Zn2Fe(CN)6s --> 2Zn2+aq + Fe(CN)64- For Zn2Fe(CN)6, Solubility = s = 3.74x10-6 M and Ksp=2.1x10-16 [Fe(CN)64-] = solubility [Zn2+] = (2)(solubility) <--- see equation above B. Ksp = [Zn2+]2[Fe(CN)64-] 2.1x10-16 = (0.1)2x Because of ...
October 4, 2008

chemistry
You have three bonding electron pairs surrounding the carbon atom, and no other electron pairs. Draw it. What is the resulting geometry? Pyramid? Trigonal planar? "T" shape?
October 3, 2008

chemistry
The only atoms with nonbonding electrons are the two oxygens on the carboxyl, -COOH group. The double bonded O has two nonbonding electrons pairs. The single bonded O has three nonbonding electron pairs. Draw a Lewis structure of the complete dipolar ion to confirm this.
October 3, 2008

ap chemistry
Both questions can be answered by substituting the informatin given into: MaVa = MbVb Ma = molarity of the acid (HCl) Va = volume of acid Mb = molarity of base (NaOH) Vb = volume of base The unknown in #1 is Vb The unknown in #1 is Mb
October 2, 2008

Physics - please help
The work done by the spring on the ball is equal to the kinetic energy of the ball as it is launched: Ek = (1/2)kx2 x is the length of compression, k is the spring constant. The velocity of the ball can be calculated by using: (1/2)mv2 = Ek Substitute the values of Ek and x. ...
October 2, 2008

physics
Fc = mv^2/r Fc is given and v is given. Substitute and solve for r
October 1, 2008

chemistry
Use the equation: A = abC, with C = concentration Do the substitutions: 0.66 = (8.2L/mol)(C) Solve for C. What are the units of your answer?
October 1, 2008

Chemistry
Convert 13.38 g Of Ag to moles by dividing by the gram-atomic mass of Ag. 1 mole of Ag produces 1 mole of AgNO3 1 mole of AgNO3 + 1 mole NaCl ---> 1 mole AgCl so..... Moles of Ag = Moles of AgNO3 = moles of NaCl (Moles of NaCl) / (molarity of NaCl) = liters NaCl
September 30, 2008

chemistry
Volume of a sphere: V = (4/3)πr3 π=3.14, and r = 1.5x10-17m Find the volume of the nucleus in m^3 1 m^3 = 1x10^6 cm^3 Convert the volume to cm^3 Substitute M in grams and V in cm^3 into: D = M/V The units of density are grams/cm^3
September 29, 2008

Chemistry
The energy needed to overcome gravity is Eg = mgy m = (159 lbs)(2.20kg/lb) = 72.3kg g = 9.8 N/kg y = (5460ft)(12in/ft)(0.02536m/in) = 1662m Substituting into the formula, you get the energy needed to climb to the top in joules. Dividing joules by 4.18 gives you calories. ...
September 29, 2008

Science/Chemistry
The reaction is: Zn(OH)2 + 2HBr ---> ZnBr2 + 2H2O This reaction shows that moles of HBr = (1/2) moles of HBr. Moles of HBr = (liters)(moles/L) or moles HBr = (0.500 L)(0.50 mol/L) = _____? moles of ZnBr2 = (1/2) moles of HBr Multiply the moles of ZnBr2 by its formula mass ...
September 28, 2008

CHEMISTRY
1. Divide 8.37x10^25 molecules of N2O4 by the number in 1 mole which is 6.02x10^23 molecules/mole. This will give you the number of moles. 2. Find the formula mass of N2O4 3. Multiply the number of moles by the formula mass to get the number of grams of N2O4
September 28, 2008

CHEMISTRY
1. Find the formula mass of FePO4 2. Divide the mass of FePO4 (285g) by the formula mass. That will give you the number of formula units or moles of FePO4
September 28, 2008

Chemistry
Your Lewis structure for BrO3^- should be trigonal planar with a double bond between the central Br atom and one of the O's. Since the double bond could be with anyone of the O's, you can draw three different resonant structures. ClO4^- is tetrahedral with only one ...
September 28, 2008

Pages: <<Prev | 1 | 2 | 3 | 4 | 5 | 6 | 7 | Next>>

Search
Members