# Posts by GK

Total # Posts: 640

Chemistry
The answer is correct except for not being labeled and not rounded off correctly.

Chemistry
The E (trans-) isomer is usually more stable because it is a less crowded structure (less steric hindrance), and because attractive intermolecular forces involving the H's are more easily formed. Building molecular models of the two kinds of isomers would help you ...

Chemistry
2K3PO4 + 3CaCl2 -> Ca3(PO4)2 + 6KCL We use the coefficients in the chemical equation to set up: (4.5 mol. CaCl2)(2 mol K3PO4 / 3 mol CaCl2) = ?? _____ moles K3PO4 Notice I used DOUBLE labels. Do the unit cancellation which can't be shown here. NOTE: The above method I ...

chemistry
1.30 M means 1.30 moles / liter of solution 1 mole CaCl2 = 111.0 g (How do you get that?) 1.30 mol x 111 g = 144.3 g CaCl2 1.00 L = 1000 mLs volume x density = mass: 1000 mLs x 1.1 g/mL = 1100 grams solution (total) 1100 g - 144.3g = 955.7 g H2O ---> 0.9553 kg H2O molality...

chemistry
• Convert 25000 miles into feet. (1 mile = 5280 ft) • time = distance / speed time = ______feet / 26.4 ft/sec = ________sec • Convert the seconds into hours ( 1 hour = 3600 sec) • Convert hours to days ( 1 day = 24 hours)

Chemistry
This is a second posting of the same question. The 120 mLs are a liquid volume and should be used only to get the mass of the alcohol. The volume of the gas would be the same as the volume of the flask. At 100 degrees C, all the alcohol would have been changed to gas with a ...

Chemistry
1 mole of C2H5OH = 12.011•2 + 1.00794•6 + 16.00 = 46.07 grams

Chemistry
Use: PV = nRT n = number of moles Find the mass of ethyl alcohol = Density x Volume in mLs Divide the mass by 1 mole C2H5OH --> n R = 0.0821 L.atm/K.mol T = 273 + 100 = 373K L = 2.00 L Substitute and solve for P

Chemistry
Each of the 11 protons in the nucleus has a charge of (+1). What is the total charge?

Chemistry
32.0 g O2 = 1 mole O2 1 mole O2 = 22.4 L The mole ratio shown by the coefficients in the chemical equation is the same as the volume (liters) ratio. So, 6 L of CO2 produce 6 L O2, or 1 L CO2 make 1 L O2 How many liters CO2 would produce 22.4 L O2 ??

Chemistry
Since the temperature is constant, the number of moles is proportional to the pressure: P1/P2 = n1/n2 P1 = 150 atm, P2 = 136 atm, n1 = 125 mol, n2 = _____? Substitute into the above equation and solve for n2 to get the moles of Ar. Convert the moles of Ar to grams (1 mole Ar...

Chemistry
Both questions have been answered previously

Chemistry
1 inch = 254 mm • Convert 754 mm Hg to inches Hg • Convert the inches Hg to feet Hg (1 feet = 12 in) • Multiply feet Hg to feet H2O by multiplying by 13.6 ft.H2O/ftHg

Chemistry
Convert all pressures to the same units, mmHg. Use the following relationships: 1 atm = 760 mmHg 1 torr = 1 mmHg 1 1 torr = 133.3 Pa

chemistry
1) (0.0307mol/L)(0.0261) = 0.00080127 moles NaOH moles NaOH = moles Acetic Acid = 0.00080127 mol 0.00080127 mol ac. acid / 0.01000 L = 0.080127 mol/L acetic acid (vinegar). 2) Since the titrated vinegar was diluted 10 times, the original vinegar was 10 times more concentrated...

chemistry
Was the purpose of the experiment to find the concentration of vinegar or the concentration of NaOH? To make any sense out of all this we must know the concentration (molarity) in moles/liter of either the acid (vinegar) or the basic (NaOH) solution. I can't find it in the...

Chemistry College (Need to know!)
Your signs on the right side are reversed. Bond breaking is endothermic and bond formation is exothermic. Some bond formations are endothermic (i.e. hydrogen bonding) that must be taken into account in conjunction with hydration which is also bond formation. ∆H(soln...

Chemistry
Notes on previous posting: 1) Correction: 5.05x10^-4 moles Cu - - - -> also moles of CuSO4 2) The data on BaSO4 confirms that the anhydrous salt is and remains CuSO4 since moles Cu = moles SO4 3) The last set of calculations gives the mole ratio of H2O/CuSO4 in the second ...

Chemistry
(0.3250)(0.09877g) = 0.03210 g Cu - - - -> also moles of CuSO4 0.03210 g Cu / 63.55 g/mol = 5.05x10^-4 moles Cu - - - - - - - - - - - - - - - - - - - - 1 mole BaSO4 = 233.4 g 0.11666g BaSO4 / 233.4 g/mole = 5.000x10^-4 moles BaSO4 (confirms mol Cu = moles SO4 as expected in...

Chemistry
Be careful with units and signs: 1) 1 L•atm = 24.2 calories 2) P•∆V work is done by the gas against the surroundings so it is negative:

Organic Chemistry
Study the references below: 1. For the R/S system in general: http://en.wikipedia.org/wiki/Chirality_(chemistry) 2. For assigning priorities: http://en.wikipedia.org/wiki/Cahn_Ingold_Prelog_priority_rules

Chemistry
The reaction is: KI(aq) + Pb(NO3)2(aq) --> 2KNO3(aq) + PbI2(s) The net reaction is the formation of the PbI2(s) as a precipitate. You figure that by applying solubility rules of ionic compounds. The net reaction includes the ions that help form PbI2(s): Pb^2+(aq) + 2I^-(aq...

Chemistry
The heat capacity 0f 4.18 J/g.ºC is equivalent to 1.00 cal/g.ºC or 1.00kcal/kg.ºC 180kcal = (1.00kcal/kg.ºC)(m)(10.0ºC) Solve for m

chemistry
Additional comments: 1) Using the Bronsted-Lowry model of acids and bases, H3O+ is an acid since it can donate a proton: H3O+(aq) + NH3(aq) --> NH4+(aq) + H2O H3O+ is not an ampholyte since it is not known to accept a proton from another proton donor (acid). It does not ...

chemistry
1) HCO3^-, Al(OH)3, and any zwiterion, are ampholytes since they can react with an acid or a base under the proper conditions. 2) H3PO4, H2PO4^-, H2SO4, etc are polyprotic acids since they have more than one acid hydrogen (can donate more than one proton)

Chemistry
The reaction is: Pb(NO3)2 + 2KI ---> PbI2(s) + 2KNO3(aq) 1) Solve: 0.781x = 25.0g (x = theoretical yield of PbI2) 2) Convert the theoretical yield of PbI2 to moles. 3) Moles of Pb(NO3)2 = moles of PbI2 = _______? 4) Convert moles of Pb(NO3)2 to grams (Multiply # moles by ...

Chemistry
The two half reaction must be reconciled on the number of electrons by multiplying the first one by 3 and the second one by 2: 3Mn(s) --> 3Mn^2+(aq) + 6e- 2Au^3+(aq) + 6e- --> 2Au(s) ---------------------------- 3Mn(s) + 2Au^3+(aq) + 6e- --> 3Mn^2+(aq) + 2Au(s) + 6e- ...

Chemistry
The half reactions are: Mn^2+(aq) + 2e- --> Mn(s) Eo = -1.18 Au^3+(aq) + 3e- --> Au(s) Eo = 1.50*** (***NOTE: That is the value I was able to find) Since Mn oxidizes more easily than Au, the Mn/Mn^2+ half reaction occurs as an oxidation: Mn(s) --> Mn^2+(aq) + 2e- Eo...

Chemistry 101
The structure of oxalic acid is shown at: (Broken Link Removed) Each carbon atom is connected to 3 other atoms (1 double and 2 single bonds). That is sp^2 hybridization. The two double bonded oxygen atoms are also sp^2 hybridized (1 double bond and 2 nonbonding electron pairs ...

Chemistry College
There is a procedure, not a formula which depends on what information is given. Tell us more.

chemistry?
# of neutrons = Mass # - atomic number # of neutrons = 28 - 14 = _____?

chemistry
Zn(s) --> Zn^2+(aq) + 2e^- (Oxidation half reaction) Cr^3+(aq) + 3e^- --> Cr(s) (Reduction half reaction)

chemistry
[H2CO3](initial) = 0.1 mol / 0.25L = 0.4M H2CO3(aq) <=> H+(aq) + HCO3(aq) (Step 1) K1 = [H+][HCO3-] / [H2CO3] HCO3-(aq) <=> H+(aq) + CO3^2-(aq) (Step 2) K2 = [H+][CO3-2] / [HCO3-] K2 = 4.7x10^-11 The hydrogen (hydronium) ion concentration depends on step one. Step...

Chemistry Redox Reaction
Cu(s)+NO3^-1(aq)-->Cu^2+(aq)+NO(g) Using the ion-electron method, 1) The incomplete half reactions are: Cu(s) —> Cu^2+(aq) NO3^-(aq) —> NO(g) 2) We use electrons, e^-, hydrogen ions, H+(aq), H2O, and OH^-(aq) to balance for electrical charge and for number ...

chemistry
Solids, and liquids (pure or nearly pure). They are not really left out. They are assigned the value of "1" (one). Example: CaCO3(s) <=> CaO(s) + CO2(g) Keq=[CO2](1) / (1) Keq = [CO2]

Chemistry
∆ = delta, not alpha C is the specific heat of the substance (water here) C = 1 cal/g.ºC (for calories C = 4.18 J/g.ºC (for joules)

chemistry
Your question is not complete. If it is about the rate law and/or the rate law constant, k, look ate 2nd example here: http://www.science.uwaterloo.ca/~cchieh/cact/c123/intratel.html

chemistry
You have not shown us how you got that answer. Method you could use: moles = (liters)(molarity) mol. HCl = (0.645L)(0.266mol/L) = _____ mol HCl (____ mol HCl)(35.453g/mole) = ______?

Chemistry
Odor is a chemical property because it is related to chemical composition. When a material is mixed with other materials and/or heated, and a new odor is detected, that means a new substance has been formed. Any change that produces one or more new substances is a chemical ...

Additional comment: 1 mole of KCl produces 2 moles of particles (ions). Because of this, a 1.00m solution of KCl would behave like a 2.00m solution as far as freezinf point, boiling point, and other colligative properties are concerned. That assumes 100% dissociation of KCl ...

1. deltaTf = 0 - (-1.0) = 1.0 deg Kf = 1.86 m = 1.0deg/1.86deg/molal unit Final answer should be OK 2. i = (molality calculated from your experiemental deltaTf) / (molality calculated from moles KCl and kilograms of water) Your answer (value of i) should be between 1 and 2, ...

Chemistry
The reaction is: Al2S3(s) + 6H2O(l) --> 2Al(OH)3(s) + 3H2S(g) (40.5gAl2S3)/(150.16 g/mol) = 0.270 moles Al2S3 (0.110 mol H2O)(1 mol.Al2S3/6mol.H2O)=0.0183mol Al2S3 NEEDED. We have 0.270 moles Al2S3 AVAILABLE. So, H2O is the limiting reagent. The moles of Al(OH)3 produced is...

chemistry
Note: I neglected to say that there are several hundred or thousands repeated units that make up the giant polymer molecules.

chemistry
A polymer molecule is one that is made of repeated segments . The repeated segments are smaller molecules (or major parts of them) that are identical, or combinations of two kinds of molecules that become parts of the repeated unit. Examples that occur naturally are DNA, ...

CHemistry
Additional Note: Intermolecular forces in general are attractions between molecules in a molecular substance. These forces determine physical properties such as boiling point (the stronger the forces the higher the BP), melting point (also the stronger the higher), vapor ...

CHemistry
Dipole attractions, London Forces and Hydrogen Bonding. For details on how they arise and how they compare, consult any chemistry textbook. Check under "intermolecular forces" or the individual names I gave you.

chemistry
The standard state for a gas is given in your chemistry textbook. The standard states for pure substances and solutes may also be given in the title of tables of thermodynamic properties. I think you can look this one up in your own textbook.

Chemistry
Net Ionic Reaction: HC2H3O2(aq) + OH^-(aq) --> C2H3O2^-(aq) + H2O Initial moles of oH- = (0.075L)(0.160mol/L) = 0.012 mol OH- or NaOH Initial Moles HOAc- = (0.025L)(0.640mol/L) = 0.016 mol HOAc Final Moles of C2H3O2^- = moles OH- (limiting reagent)= 0.012 Final moles of ...

Chemistry
Looks OK

Chemistry
K = [SO3][NO]/[SO2][NO2] K = (3.0)(2.0)/(4.0)(0.5)= 3.0 (a) Some of the added NO2 will be used up causing a shift to the right. Let that be equal to x. At the new equilibrium, [SO2]=4.0-x, [NO2]=0.5+1.5-x=4.0-x [NO]=2.0+x, [SO3]=3.0+x, Set up: K = [3.0+x][2.0+x]/[4.0-x][2.0-x...

chemistry
My attempt to draw the structural formula for NH3 did not work out. The downward -H bond should be linked to N (nitrogen).

chemistry
Structural formulas show how atoms are linked to one another in a formula. For example, for CO2 the structural formula is O=C=O. For NH3 it is H-N-H | H It is difficult to show structural formulas here. Here are some more in the in the web page below: http://www.cartage.org.lb...

chemistry
You have a hint on that in my original answer: "It would be difficult in terms of flask sizes and pipette sizes available to achieve dilution by a large factor in one step." That means that using the serial dilution method we can prepare very dilute solutions in a ...

chemistry
Serial dilution is starting with a stock solution, then diluting it, for example, 10 times. If we dilute the first dilution 10 times, we get a second dilution which is 100 times more dilute than the stock solution. We can continue to dilute the last dilution and achieve a ...

Chemistry
P1V1/T1 = P2V2/T2 (765mmHg)(35.5L)/273K = (699.2mmHg)(56.0L)/T2 Solve for T2 to get the final temperature in degrees Kelvin. If you need degrees Celsius, use: C = K - 273

Chemistry
Not sure if a molecular orbital energy diagram is available for diatomic molecules involving third row elements like Cl. Based on more elementary bonding theory, we could assume a bonding order of 1 since ClF obeys the Octet Rule and we can assume SP3 hybrid orbitals for both...

Chemistry
1. Convert 40 mg/L Cl^-, 100 mg/L SO4^2-, and 10 mg/L NO3^- into moles/liter using the formula masses for Cl, SO4, and NO3. 2. Add the moles of the three anions to get the total moles/liter. 3. Convert the total moles/L to grams of Na+/L by multiplying the total moles/L by the...

chemistry
Two things are wrong with that equation: (a) Aluminum does not react with nitric acid. (b) If we assume the reaction does occur, aluminum metal oxidizes (goes from an oxidation state of 0 to +3) but no element is reduced as required (experiences a lowering of its oxidation ...

Chemistry
Zinc has only one ionic charge, the one you found.

chemistry
The atomic mass number is equal to the sum of the (number of protons) + ( number of neutrons). Which of your two numbers is equal to that?

chemistry
• Count the total number of valence electrons. • Link the central atom to the outer atoms with shared electron pairs. Count the shared electrons. • Complete the octets of the outer atoms. • Subtract (Total number - Shared number ) = ___? That is the number ...

Chemistry-Repost
Let [H+] = x Ka = [H^+][C3H2NO2^-] / [HC3H2NO2] 3.55x10^-3 = x^2 / (0.4-x) •For an exact solution, you must convert the previous equation to a quadratic trinomial equal to 0, the solve. •For an approximate solution, you assume that (0.4-x)=0.4, when x is much smaller...

chemistry
The number of valence electrons in the entire molecule is 2x5 for the two nitrogen atoms and 4x6 for the four oxygen atoms. Total # of valence electrons=2x5+4x6=34 electrons or 17 electron pairs. We link the two N's together by a double bond (two shared electron pairs). ...

Chemistry
The half reactions in net ionic form are: Mg --> Mg^+2 + 2e^- (oxidation) Fe^+3 + 3e^- --> Fe (reduction)

Chemistry
Both. the number of atoms of each kind, and the mass are conserved.

Chemistry
Convert the number of atoms to moles by dividing by 6.02x10^23 atoms/mole. Once you have the number of moles, you multiply by the formula mass ( grams/mole) to get the number of grams.

chemistry
The two-step decomposition you described is: (a) PbO2 --> Pb3O4 + O2 Balancing it, 3PbO2 ---> Pb3O4 + O2 (b) Pb3O4 ---> PbO + O2 or, balanced, 2Pb3O4 ---> 6PbO + O2 In each step, all atoms are accounted for. However the first step must be doubled to reconcile it ...

chemistry
(a) (325mg)(0.001g/1.00mg)=0.325g The conversion factor is (0.001g/1.00mg) (b) (0.325g)(1 moleASA/180.2g) = _______moles ASA Can you pick the conversion factor in this step? Note: The conversion of 325mg to moles can be done in two separate steps as shown above or in a single...

science(chemistry)
The unknown solid should not have too high a solubility in the wash liquid. The idea is to dissolve and remove impurities without losing the unknown solid with the wash. The safest choice of wash liquid is the same liquid in which the solid formed.

Chemistry
Go to the link below and scroll to a table of the most common ions and their charges: http://en.wikipedia.org/wiki/Ion

chemistry
The most likely reaction is double replacement.

chemistry
Find the Metal Activity Series chart in your chemistry book. The above reaction will occur if Ni is higher on the chart than Mg. Otherwise, no reaction occurs. You can also find the activity series below: (Broken Link Removed)

Chemistry
1. HCl is highly dissociated since it is a strong acid. It produces a high concentration of hydrogen ions, H+(aq) in a water solution which are the same as hydronium ions, H3O+. Acetic acid, HC2H3O2, is made of molecules that do not dissociate. Its concentration of hydrogen (...

Chemistry
The net reaction is between hydronium, H3O+, ions and the metal, producing metal anions and hydrogen gas. A strong acid solution has a higher concentration of hydronium ions that a week acid. The rate is higher when the concentration of any one of the reactants is higher.

Chemistry
Use the "dilution formula": V1C1 = V2C2 V1, C1 = initial volume and concentration V2, C2 = final volume and concentration Your unknown is V1. Substitute the other which are given and solve for V1.

Chemistry
Use the "dilution formula": V1C1 = V2C2 V1, C1 = initial volume and concentration V2, C2 = final volume and concentration Your unknown is V1. Substitute the other which are given and solve for V1.

chemistry
% = (100)*(grams solid) / (Total mass)

Chemistry
The Group I anion has been oxidized to its molecular form: Br2 or I2 in the earlier steps. When you shake two layer mixture, the molecular (as opposed to ionic) Br2 or I2 are extracted into the hexane layer and give it the characteristic color or of one of those molecular forms.

chemistry
For the disadvantages check the link given to you by DrBob. The main advantage is that calcium ions in solution precipitate as calcium phosphate thus removed from the water.

Chemistry
Set up a 2nd class lever (Fulcrum at one end, Effort at the other end and Load in the middle. Pull the effort end using a fixed pulley with the nitinol wire replacing the string. If the nitinol wire gets kinky, try heating or cooling it and observe what happens. Not sure if ...

chemistry
" ..It's the math, true enough, but it's also the drawing..". I think that is equivalent to my terse Both. The procedure for writing Lewis structures can't be fully demonstrated on a bulletin board posting like this one. Using some trial and error within ...

chemistry
Both.

chemistry
You must write a Lewis structure that obeys the Octet Rule. You start by counting the number of valence electrons on the two central atoms, N(5), O(6), and the three H's (1 each). Electrons must be shared so that N and O end up with 8 electrons around them (shared and ...

Chemistry
I gave you the background information needed to draw your own conclusions.

Chemistry
The ions making up borax have much more freedom of movement in solution. Also, the chemical species in solution are more mixed up than they would be in separate phases. What would that do to the total entropy of system?

chemistry
Density is related to intermolecular or other inter-particle distances. These are dependent on molecular or ionic radii, intermolecular attractions (or other cohesive forces), dispersive forces (repulsions) and molecular kinetic energies (molecular speeds). All these factors ...

Chemistry
We have two ions: Li+ and H :-

Chemistry
<h3> We have two ions: Li+ and H : - </h3>

Chemistry
Convert 109g F2 to moles. Convert 3,4000mL(?) to liters. Convert 20ºC to degrees Kelvin R = 0.0821 L.atm/ºK.mol Substitute into PV = nRT Solve for P

chemistry

chemistry

Kc =[ Fe+3] / [Fe+2][Ag+] You must be given the equilibrium constant or have access to enough information to calculated it. Since you have the initial concentrations of Fe^+2, Ag^+ and Fe^+3 with a known Kc, you can set up a table of data leadinf to an equation for changes in...

chemistry need help
1. Divide the grams of aluminum by the molar mass of aluminum (26.98g/mole) to convert mass to moles. 2. Multiply the number of moles of aluminum by Avogadro's Number (6.02x10^23 atoms/mole).

science(chemistry)
Either method works. Which method you select depends on how you graphed your calibration graph using standard solutions over a range of concentrations. For more information, download the online PDF file: http://www.ffcr.or.jp/zaidan/FFCRHOME.nsf/...

chemistry
A metal acts as oxidizing agent as it gets reduced by taking electrons away from another metal. Example: Cu^+2(aq) + Ni --> Cu(s) + Ni^+2(aq) Cu(s) + Ni^+2(aq) --> No Reaction You are comparing the activity of these metals in their ionic form. Which is more active, Ni^+2...

Chemistry
• The heat released by the quarter pounder is: heat = (1.00 kcal/kg.ºC)(5.00 kg)(82.8ºC) = 414 kcal • 1 kcal is the same as 1 Cal, so we have 414 Cal/quarter-pounder • If it takes 100 Cal / mile, you should be able to find the number of miles you can ...

CHEMISTRY
M1*V1 = M2*V2 (0.225M)(45.0mL) = (0.155M)(V2) Solve for V2 and subtract 45.0 to get the volume of water that must be added to get the final volume.

chemistry
a). Multiply the atomic mass of Al by 2 = _____? b). Multiply the atomic mass of O by 3 = _____? c). Add (a) and (b) to get the formula mass of Al2O3 d). Find the % of Al in Al2O3: %Al = [(a)/(c)]*(100) e). Multiply the mass of Al2O3 given in the question by the % of Al. ...

chemistry
For dilution problems (preparing a weaker solution from a stronger stock solution) use: V1M1 = V2M2 (1.00M)(V1) = (0.240M)(2.00L) Solving for V1, V1 = (0.240M)(2.00L) / (1.00M) = ? The second part, I don't quite follow.

Chemistry
Organic solvents consist generally of non-polar molecules. Ionic compounds are made of electrically charged particles which are not attracted strongly by non-polar molecules. Covalent (molecular compounds) tend to dissolve in solvents with similar structure. Most organic ...

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