Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
You are given 2.677 g of a mixture of KClO3 and KCl. When heated, the KClO3 decomposes to KCl and O2, 2 KClO3 (s) → 2 KCl (s) + 3 O2 (g), and 605 mL of O2 is collected over water at 28 °C. The total pressure of the gases in the collection flask is 763 mm Hg. What is ...
Saturday, December 1, 2012 at 12:11am

CHEMISTRY
Use the Nernst equation and calculate Ecell for each of the following cells. Enter your answer with 3 significant digits. Enter scientific notation as 1.23E4. (a) Mn(s) | Mn2+(0.11) M || Cr3+(0.24 M), Cr2+(0.11 M) | Pt(s) ____________ (b) Mg(s) | Mg2+(0.070) M || [Al(OH)4]&#...
Friday, November 30, 2012 at 11:52pm

Chemistry
Consider the following: CH4, SiH3Cl, Ar, and CH2F2. (a) Which one will diffuse the fastest? (b) What is the rms speed (m/s) of the slowest-moving atom or molecule at 25°C?
Friday, November 30, 2012 at 11:47pm

Chemistry
not much of a question but more of an appreciation, thanks for helping i was really confused before today
Friday, November 30, 2012 at 11:40pm

chemistry
Reaction: CaCO3 + 2 HCl -> CaCl2 + CO2 + H2O Calculate the molarity of hydrochloric acid solution if an initial mass of 4.568g of CaCO3 was reacted with 25.0mL of the acid and 2.678g of CaCO3 remain after the reaction is complete.
Friday, November 30, 2012 at 11:39pm

CHEMISTRY
Use the Nernst equation to calculate Ecell for each of the following cells. Enter your answer with 3 significant digits. Enter scientific notation as 1.23E4. (a) Mn(s) | Mn2+(0.11) M || Cr3+(0.24 M), Cr2+(0.11 M) | Pt(s) ____________ (b) Mg(s) | Mg2+(0.070) M || [Al(OH)4]–...
Friday, November 30, 2012 at 11:35pm

CHEMISTRY
Enter part(a), (c) with 2 siginificant digits and part(b) with 3 siginificant digits. Enter scientific notation as 1.23E4. (a) What is Ecell if the unknown solution in the half-cell on the left has pH = 4.94? ____________ (b) What is Ecell if the unknown solution in the half-...
Friday, November 30, 2012 at 11:26pm

CHEMISTRY
Use the Nernst equation and data from Appendix D to calculate Ecell for each of the following cells. Enter your answer with 3 significant digits. Enter scientific notation as 1.23E4. (a) Mn(s) | Mn2+(0.11) M || Cr3+(0.24 M), Cr2+(0.11 M) | Pt(s) ____________ (b) Mg(s) | Mg2+(0...
Friday, November 30, 2012 at 11:23pm

CHEMISTRY
cell diagram:H2(g,1atm) Pt Enter part(a), (c) with 2 siginificant digits and part(b) with 3 siginificant digits. Enter scientific notation as 1.23E4. (a) What is Ecell if the unknown solution in the half-cell on the left has pH = 4.94? ____________ (b) What is Ecell if the ...
Friday, November 30, 2012 at 11:17pm

CHEMISTRY
The standard electrode potential for the reduction of Eu3+(aq) to Eu2+(aq) is −0.43 V. determine which of the following is capable of reducing Eu3+(aq) to Eu2+(aq) under standard-state conditions? (a) Sn2+(aq) (b) ln(s) (c) HCN(aq) (d) La(s)
Friday, November 30, 2012 at 11:14pm

Chemistry
What is the molarity of a solution prepared by diluting 25.0 mL of 0.412 M magnesium nitrate to a volume of 1.50 L please help!
Friday, November 30, 2012 at 10:50pm

Chemistry
Lead(II) oxide from an ore can be reduced to elemental lead by heating in a furnace with carbon. PbO(s) + C(s)= Pb(l) + CO(g) Calculate the expected yield of lead if 90.0 kg of lead oxide is heated with 90.0 kg of carbon.
Friday, November 30, 2012 at 10:38pm

Chemistry
An experiment that led to the formation of the new field of organic chemistry involved the synthesis of urea, CN2H4O, by the controlled reaction of ammonia and carbon dioxide. 2 NH3(g) + CO2(g)= CN2H4O(s) + H2O(l) What is the theoretical yield of urea when 100. g of ammonia is...
Friday, November 30, 2012 at 10:24pm

Chemistry
consider 1.0 L of a solution which is 0.55 M HF and 0.2 M NaF (Ka for HF = 7.2 x 10-4). Calculate the pH after 0.10 mol of HCl has been added to the original solution. Assume no volume change on addition of HCl. Goes along with the last one i posted, i know i have to realize ...
Friday, November 30, 2012 at 10:04pm

chemistry
Reaction: Na2CO3 + 2 HCl -> 2 NaCl + CO2 + H2o How many grams of NaCl can be produced from the reaction of 1.35g of Na2CO3 with 125mL of 0.265 M HCl?
Friday, November 30, 2012 at 9:59pm

Chemistry
consider 1.0 L of a solution which is 0.55 M HF and 0.2 M NaF (Ka for HF = 7.2 x 10-4), Calculate the pH of this solution
Friday, November 30, 2012 at 9:30pm

chemistry
Calculate the molarity of a solution containing 58.5mg of NaCl in 2.50mL of solution.
Friday, November 30, 2012 at 9:20pm

Physical Chemistry
Calculate DS if the temperature of 3 moles of an ideal gas with Cv,m = 1.5R is increased from 200 K to 500 K under conditions of (a) constant pressure and (b) constant volume.
Friday, November 30, 2012 at 8:43pm

Physical Chemistry
Evaluate (dS/dV)T for a van der Waals gas and a perfect gas
Friday, November 30, 2012 at 8:39pm

CHEMISTRY
2.05 Grams of a liquid vaporized at 80 c in a 1 liter flask and a pressure of 1 atm. what is the molar mass of the gas?
Friday, November 30, 2012 at 8:25pm

Chemistry
Is lead non-polar covalent, polar covalent, ionic, network, or metallic and why?
Friday, November 30, 2012 at 7:26pm

Chemistry
When solutions of KCl and Pb(NO3)2 are mixed, a precipitate forms. Which of the following is the balanced equation for the double replacement reaction that occurs? a. KCl(aq) + Pb(NO3)2 (aq) ¨ KNO3 (aq) + PbCl2 (s) b. KNO3 (aq) + PbCl2 (s) ¨ KCl(aq) + Pb(...
Friday, November 30, 2012 at 6:37pm

chemistry
The number of moles in 15.39g of C2H6O?
Friday, November 30, 2012 at 6:00pm

Into. Chemistry
I'm trying to do this precipitation reaction problem, but I don't understand part of it. The question is: Does a precipitate form when aq. soultions of potassium nitrate (KNO3) and sodium iodide (NaI) are mixed? Then it lists the solutions for the two: KNO3(aq) --> ...
Friday, November 30, 2012 at 4:18pm

CHEMISTRY
What is oxygen extensive properties?
Friday, November 30, 2012 at 3:04pm

science, chemistry
Separate this redox reaction into its component half-reactions. O2+2Cu---->2CuO thought it was: Oxidation 2e-+O2---->2O(-2) Reduction Cu---->Cu(2+)-2e- but this is wrong
Friday, November 30, 2012 at 2:34pm

chemistry
what is cryogenetics
Friday, November 30, 2012 at 1:58pm

chemistry... HELPP
Pyridine is a weak base that is used in the manufacture of pesticides and plastic resins. It is also a component of cigarette smoke. Pyridine ionizes in water as follows: C5H5N + H2O<-->C5H5NH+ + OH- The pKb of pyridine is 8.75. What is the pH of a 0.190 M solution of ...
Friday, November 30, 2012 at 1:56pm

chemistry
a. what is the effect on the Kc when the temperature of an exothermic reaction is lowered? b. according to Le Chatelier's principle, how is equilibrium in part a established.
Friday, November 30, 2012 at 10:03am

chemistry
Calculate the density of atoms along [011] in molybdenum (Mo) . Use only the information provided in your class Periodic Table, and express your answer in units of atoms/cm
Friday, November 30, 2012 at 9:35am

Chemistry
Your x-ray lab has a monochromator consisting of a single crystal of nickel cut so that the (001) plane lies in the cube face. At what angle (in degrees) should the cube face be tilted with respect to the incident beam in order to select radiation with a wavelength ë=3....
Friday, November 30, 2012 at 9:34am

Analytical Chemistry
How many mg of X is contained in 25 ml of a solution giving an absorbance of 0.250 at 400 nm when measured with a 1 cm cell ?
Friday, November 30, 2012 at 6:19am

General Chemistry
Titration between iodine and thiosulphate. Why starch solution has to be added when the solution just turned pale yellow, but not at the beginning of reaction?
Friday, November 30, 2012 at 6:10am

Analytical Chemistry
How many mg of X is contained in 25 ml of a solution giving an absorbance of 0.250 at 400 nm when measured with a 1 cm cell ?
Friday, November 30, 2012 at 6:00am

chemistry
A student measures the conductivity of a KNO3 solution and determines it to be a strong electrolyte. the student incorrectly lists the species in solution as KNO3,K+, NO3. Give the correct list of species in solution? Please help I am lost
Friday, November 30, 2012 at 3:27am

chemistry
I need the pre lab anwsers to 22, I have been studying for a test and have not finished them
Friday, November 30, 2012 at 3:22am

CHEMISTRY
Cant figure this out, I feel like the answer I keep getting is way too low. A voltaic cell is constructed that is based on the following reaction: Sn2+ (aq) +Pb(s) = Sn(s) + Pb2+ (a) If the concentration of Sn2+ in the cathode compartment is 1.00M and the cell generates an emf...
Friday, November 30, 2012 at 1:43am

Chemistry
If saturated solution of barium chloride at 30 degree Celsius contains 150g water how much additional barium chloride can be dissolved by heating it to 60 degree Celsius? 30 degrees Celsius = 38.2 60 degrees Celsius = 46.6
Friday, November 30, 2012 at 1:20am

chemistry
The fictitious compound, arrhenium fluoride (AhF), reacts with itself to form a dimer with the formula Ah2F2. The reaction is second order in AhF. The value of the rate constant is 5.591×10−3 M−1s−1. What is the initial rate of reaction in a reactor ...
Friday, November 30, 2012 at 12:30am

CHEMISTRY
Co(s) will oxidize Fe(s) while leaving Cu(s) unreacted, please write a balanced equation for the reagent involved?
Friday, November 30, 2012 at 12:20am

Chemistry
Astronomers have detected hydrogen atoms in interstellar space in the n=732 energy level. Suppose an atom in this excited state emits of a photon and undergoes a transition from n=732 to n=632. How much energy does the atom lose as a result of this transition? what is the ...
Thursday, November 29, 2012 at 11:11pm

chemistry
ph of 10 grams of sodium acetate and 100 mL of .5M acetic acid
Thursday, November 29, 2012 at 9:42pm

Chemistry - Melting Ice
The heat of fusion of ice is 6.00 kJ/mol. Find the number of photons of wavelength = 6.78×10^−6 m that must be absorbed to melt 6.80 g of ice.
Thursday, November 29, 2012 at 9:33pm

Chemistry
Hi everyone, I have been trying to figure out this titration equation all day and for some reason I am stumped. Here is the question in full: Potassium hydrogen phthalate, KHP, can be obtained in high purity and is used to determine the concentrations of solutions of strong ...
Thursday, November 29, 2012 at 8:36pm

chemistry
what mass of aluminum hydroxide needs to be consumed to neutralize 1.25L of stomach acid (HCl). Stomach acid has a pH of 2.2
Thursday, November 29, 2012 at 8:35pm

chemistry
how may grams are in 6.1 moles of AIN
Thursday, November 29, 2012 at 8:30pm

chemistry
The fictitious compound, arrhenium fluoride (AhF), reacts with itself to form a dimer with the formula Ah2F2. The reaction is second order in AhF. The value of the rate constant is 2.591×10−3 M−1s−1. What is the initial rate of reaction in a reactor ...
Thursday, November 29, 2012 at 7:55pm

chemistry
What is the acid dissociation constant for a 0.010 M solution of the unkown acid HX that has a pH of 2.70 at equilibrium? I know the answer but not how to get it, please help? Thanks in advance.
Thursday, November 29, 2012 at 7:52pm

Chemistry
A propane stove burned 470. grams of propane and produced 625 milliliters of water. What is the % yield? C₃H₈+5O₂ -> 3CO₂+ 4H₂O
Thursday, November 29, 2012 at 7:35pm

CHEMISTRY
A 0.02718 mg sample of an unknown compound was found to contain 0.0094 mg of Fe, and 0.0178 mg of Cl. It was also determined that the unknown compound had a molecular weight of 162.10 g/mol. What is the molecular formula for this compound?
Thursday, November 29, 2012 at 7:28pm

CHEMISTRY HWK MAKES NO SENSE
How many grams of C are required to make 464.99 grams of this compound? compound= C3H8
Thursday, November 29, 2012 at 7:02pm

chemistry
Cisplatin, a drug used in the treatment of certain types of cancer has the molecular formula Pt(NH3)2Cl2. How many moles of compound are in 254.09 grams of the compound?
Thursday, November 29, 2012 at 6:27pm

CHEMISTRY
how many atoms of C are present in 315.93 g (6.79e24 molec) of CO?
Thursday, November 29, 2012 at 6:01pm

Chemistry
What's the linear density of body center cubic (0,1,1)of Molybdenum
Thursday, November 29, 2012 at 3:19pm

chemistry
Mg + Au+ -> Mg2+ + Au what is the oxidation and reduction half reactions
Thursday, November 29, 2012 at 2:21pm

Chemistry
Consider an ionic compound, MX2, composed of generic metal M and generic halogen X. The enthalphy of formation of MX2= -891. The enthalphy of sublimation of M= 141. The first and second ionization energies of M are 605 and 1392. The electron affinity of X= -339. The bond ...
Thursday, November 29, 2012 at 1:05pm

chemistry
A gas is collected over water at 20 degrees Celsius at a pressure of 752 mm. What is the pressure of the pure gas?
Thursday, November 29, 2012 at 11:28am

chemistry
N2O5 dissolved in CCl4 decomposes to give N2O4 and O2. The reaction is first order with a half-life of 1234 seconds. How long will it take, in seconds, for the concentration of N2O5 to fall to 1.1% of its initial value?
Thursday, November 29, 2012 at 10:23am

chemistry
The fictitious compound, arrhenium fluoride (AhF), reacts with itself to form a dimer with the formula Ah2F2. The reaction is second order in AhF. The value of the rate constant is 6.091×10−3 M−1s−1. What is the initial rate of reaction in a reactor ...
Thursday, November 29, 2012 at 10:20am

Chemistry
An unknown solution may contain one of the ions of the pair below. Devise a test which allows you to distinguish between the ions. Cu2+(aq) and Co2+ (aq)
Thursday, November 29, 2012 at 10:00am

CHEMISTRY
Urbium (Ur) is an upscale element found in big cities. Its oxide (UrO2) is not very stable and decomposes readily at temperatures exceeding 66∘ C. The figure below shows how the rate of reaction varies with the concentration of UrO2 at 75∘ C. The rate r is in units...
Thursday, November 29, 2012 at 9:40am

chemistry
Administratium bromide (AdBr) decomposes readily at temperatures exceeding 37°C. The figure below shows how the rate of reaction varies with the concentration of AdBr. The rate, r, is in units of M s-1 and the concentration of AdBr, c, is in units of M (mole L-1). The ...
Thursday, November 29, 2012 at 9:26am

chemistry
A steel cable 10 m long is pulled in tension with a stress of 350 MPa. Assume that the Young's modulus of the steel cable is about 200 GPa. If only elastic deformation occurs, what is the resultant elongation in cm?
Thursday, November 29, 2012 at 9:10am

chemistry
The fictitious compound, arrhenium fluoride (AhF), reacts with itself to form a dimer with the formula Ah2F2. The reaction is second order in AhF. The value of the rate constant is 6.091×10−3 M−1s−1. What is the initial rate of reaction in a reactor ...
Thursday, November 29, 2012 at 9:02am

chemistry
Its general formula is BaTi(SiO3)3.If a 15-carat stone were pure BaTi(SiO3)3, how many moles of silicon would it contain? (There are exactly 5 carats per gram.)
Thursday, November 29, 2012 at 7:34am

chemistry
While you are at rest, your brain gets about 15% by volume of your blood. If your body contains 5.2 L of blood, how many liters of blood are in your brain at rest? and how many quarts?
Thursday, November 29, 2012 at 7:31am

chemistry
Normal glucose levels in the blood are from 70 to 110 mg glucose per 100 mL of blood. I the level falls too low, there can be brain damage. If a person has a glucose level of 108 mg/100 mL, what is the total mass of glucose in grams in 5.10L of blood?
Thursday, November 29, 2012 at 7:30am

Chemistry
At T = 25 degrees Celsius, the reaction No2 <-> 2NO +O2 has an equilibrium constant K=5.0*10^-13. Suppose the container is filled with NO2 at an initial pressure of 0.25 atm. Calculate the partial pressure of NO at equilibrium
Thursday, November 29, 2012 at 5:09am

chemistry
How would you prepare the following solution? a)2% NaCL(w/v) b).35M glucose C)0.12M CaCl2 For b I got glucose 0.35=wt/180=63gm/L, but not sure if I'm doing it right.
Thursday, November 29, 2012 at 2:34am

Chemistry
How do you convert -2.1786*10^-18 J to kj/mole and this is the energy released when an electron is added to hydrogen nucleus. I been trying to figure this out for 30 mins and I still didn't get it please help
Thursday, November 29, 2012 at 1:55am

Chemistry
Calculate the energy released when an electron is added to a hydrogen nucleus. Assume the transition is n= infinite to n=1. I know equation to use but how do I calculate when n is infinite and no number ?? Please some help
Thursday, November 29, 2012 at 12:39am

Chemistry
H6P8: Elongation A steel cable 10 m long is pulled in tension with a stress of 350 MPa. Assume that the Young's modulus of the steel cable is about 200 GPa. If only elastic deformation occurs, what is the resultant elongation in cm?
Thursday, November 29, 2012 at 12:13am

Chemistry
H6P7: Young's Modulus Rank the following 3 classes of materials in order of increasing typical Young's Modulus: metals such as copper, plastics such as HDPE (high density polyethelene), and ceramics such as alumina (Al2O3). Do not look up the values of Young's ...
Thursday, November 29, 2012 at 12:13am

Chemistry
H6P6: Urbium Oxide First Part of the Question: Urbium (Ur) is an upscale element found in big cities. Its oxide (UrO2) is not very stable and decomposes readily at temperatures exceeding 66∘ C. The figure below shows how the rate of reaction varies with the concentration...
Thursday, November 29, 2012 at 12:11am

Chemistry
N2O5 dissolved in CCl4 decomposes to give N2O4 and O2. The reaction is first order with a half-life of 1234 seconds. How long will it take, in seconds, for the concentration of N2O5 to fall to 1.1% of its initial value?
Thursday, November 29, 2012 at 12:07am

Chemistry
Administratium bromide (AdBr) decomposes readily at temperatures exceeding 37°C. The figure below shows how the rate of reaction varies with the concentration of AdBr. The rate, r, is in units of M s-1 and the concentration of AdBr, c, is in units of M (mole L-1). The ...
Thursday, November 29, 2012 at 12:07am

Chemistry
The fictitious compound, arrhenium fluoride (AhF), reacts with itself to form a dimer with the formula Ah2F2. The reaction is second order in AhF. The value of the rate constant is 4.091×10−3 M−1s−1. What is the initial rate of reaction in a reactor ...
Thursday, November 29, 2012 at 12:06am

Chemistry
You have a single crystal of 100% pure gold. Identify which of the following defects you would expect to be present at room temperature. Free surface Grain boundaries Vacancies Inclusions Substitutional impurity atoms Interstitial impurity atoms
Thursday, November 29, 2012 at 12:06am

Chemistry
Metals yield at a stress much lower than those calculated on the basis of their bond strength alone. This is explained by the presence of defects. Identify the principal defects responsible for this observation. A)Grain Boundaries B)Interstitial Metal Atoms C)Vacancies D)...
Thursday, November 29, 2012 at 12:05am

chemistry
What is the minimum volume of 2.00 M HCl necessary to neutralize completely the hydroxide in 800.0 mL of 0.3 M NaOH?
Wednesday, November 28, 2012 at 11:45pm

CHEMISTRY
Suppose that you have 0.500 L of each of the following solutions, and an unlimited supply of water. (Note: C9H7NHBr is a salt containing the ions C9H7NH+ and Br- and C9H7N is quinoline, an organic base with pKb = 6.24 at 298 K. If you like, you may represent C9H7NH+ as HB+ and...
Wednesday, November 28, 2012 at 11:38pm

CHEMISTRY
Ethylamine, CH3CH2NH2, is an organic base with pKb = 3.367 at 298 K. In an experiment, a 40.0 mL sample of 0.105 mol L-1 CH3CH2NH2 (aq) is titrated with 0.150 mol L-1 HI(aq) solution at 298 K. (1a) Write a balanced chemical equation for the neutralization reaction upon which ...
Wednesday, November 28, 2012 at 11:36pm

Chemistry
Equal masses of P and Cl react according to the following equation: 2P + 3Cl2 --> 2PCl3 Identify which reagent is in excess. Calculate the percent that will remain at the end of the reaction.
Wednesday, November 28, 2012 at 10:45pm

Chemistry
What happens when NaCl(aq) and AgNO2(aq) are mixed? Also, will the mass increase, decrease, or stay the same after the mixing? Why? Thanks!
Wednesday, November 28, 2012 at 10:31pm

Chemistry
The most abundant isotope of uranium,238U , does not undergo fission. In a breeder reactor, however, a 238U atom captures a neutron and emits two beta particles to make a fissionable isotope of plutonium, which can then be used as fuel in a nuclear reactor.Write the balanced ...
Wednesday, November 28, 2012 at 10:04pm

Chemistry
You have a single crystal of 100% pure gold. Identify which of the following defects you would expect to be present at room temperature.
Wednesday, November 28, 2012 at 9:02pm

CHEMISTRY
An equilibrium mixture of the following reaction was found to have = 0.0325 at 1200 degrees C. What is the concentration of I? I2(g)<->2I (g) Keq=1.3×10−2 at 1200
Wednesday, November 28, 2012 at 8:56pm

Chemistry
The binding energy of electrons in a metal is 194 kJ/mol. Find the threshold frequency of the metal. ----------------- The heat of fusion of ice is 6.00 kJ/mol. Find the number of photons of wavelength = 6.78×10^−6 m that must be absorbed to melt 6.80 g of ice.
Wednesday, November 28, 2012 at 8:07pm

Chemistry
according to the bohr model of the hydrogen atom, what is the closest an electron can get to the nucleus? What is the farthest it can get from the nucleus? ( if the latter answer seems absurb, it might amuse you to know that it is the same value predicted by present-day ...
Wednesday, November 28, 2012 at 7:40pm

Chemistry
You have a single crystal of 100% pure gold. Identify which of the following defects you would expect to be present at room temperature. Free Surface Gain Boundaries Vacancies Inclusions Substitutional impurity atoms interstitial impurity atoms. Thank you.
Wednesday, November 28, 2012 at 7:32pm

Chemistry
Balance the following equations: A. N2O>N2+O2 B. HBr>H2+Br2 C. CH4+O2>CO2+H2O
Wednesday, November 28, 2012 at 6:53pm

Chemistry
What is C2H5OH+3O2>CO2+H2O balanced?
Wednesday, November 28, 2012 at 6:51pm

chemistry
Sodium-24, a beta-emitter used in diagnosing circulation problems, has a half-life of 15 hours.Write the balanced nuclear equation for this emission.
Wednesday, November 28, 2012 at 6:05pm

chemistry
Please help with the products: NaHCO3+H2SiF6= ????
Wednesday, November 28, 2012 at 5:25pm

Chemistry
I am not sure if I calculated the exact molarity of the potassium permanganate. I multiplied the molarity of the potassium permanganate by the liters of potassium permanganate used in the titration and divided it by the total liters of solution. I don't know if that if how...
Wednesday, November 28, 2012 at 4:34pm

Jennifer
How to balance the following equation: I2 + Cl- = ?
Wednesday, November 28, 2012 at 3:08pm

Chemistry
What is the final volume (L) of a 1.00 L system at 315 K and 1.10 atm if STP conditions are established?
Wednesday, November 28, 2012 at 2:56pm

chemistry
At constant volume, the heat of combustion of a particular compound is –3334.0 kJ/mol. When 1.569 g of this compound (molar mass = 125.76 g/mol) was burned in a bomb calorimeter, the temperature of the calorimeter (including its contents) rose by 5.173 °C. What is the...
Wednesday, November 28, 2012 at 2:35pm

Chemistry
In a constant-pressure calorimeter, 50.0 mL of 0.320 M Ba(OH)2 was added to 50.0 mL of 0.640 M HCl. The reaction caused the temperature of the solution to rise from 23.47 °C to 27.83 °C. If the solution has the same density and specific heat as water, what is ΔH ...
Wednesday, November 28, 2012 at 2:33pm

chemistry
calculate the amount (g) needed to make 25 ml of 0.1 m co(no3)2 6h2o
Wednesday, November 28, 2012 at 12:55pm

Chemistry
If 22.15 milliliters of 0.100 molarity sulfuric acid is required to neutralize 10.0 milliliters of lithium hydroxide solution, what is the molar concentration of the base?
Wednesday, November 28, 2012 at 12:49pm

Chemistry
How many kilograms of chalcopyrite must be mined to obtain 315g of pure Cu?
Wednesday, November 28, 2012 at 12:33pm

Chemistry
What is the chemical breakdown of a cheese pizza
Wednesday, November 28, 2012 at 11:54am

chemistry
Naphthalene, commonly known as moth balls, is composed of 93.7% carbon and 6.3% hydrogen. determine the empirical for naphthalene. molecular formula for Naphthalene. Determine the number of empirical formulas you would need to make a full naphthalene molecule.
Wednesday, November 28, 2012 at 11:39am

chemistry
Vanadium oxide is used as an industrial catalyst. The percent composition of this oxide is 56.0% vanadium and 44.0% oxygen. Determine the empirical formula for vanadium.
Wednesday, November 28, 2012 at 11:37am

chemistry
what is the pH of a 0.10 M solution of methylamine (CH3NH2, kb= 4.4*10^-4) at 25 degree C?
Wednesday, November 28, 2012 at 10:29am

chemistry
what is the pH of a 0.10 M solution of methylamine (CH3NH2, kb= 4.4*10^-4) at 25 degree C?
Wednesday, November 28, 2012 at 10:28am

CHEMISTRY
1. Suppose that you have 0.500 L of each of the following solutions, and an unlimited supply of water. (Note: C9H7NHBr is a salt containing the ions C9H7NH+ and Br− and C9H7N is quinoline, an organic base with pKb = 6.24 at 298 K. If you like, you may represent C9H7NH+ ...
Wednesday, November 28, 2012 at 9:28am

CHEMISTRY
The half-cell, Tl | Tl+(1 mol L-1), is connected to a Pt | H+ | H2(1 atm) half-cell in which the concentration of H+ is unknown. The measured cell voltage is 0.0841 V and the Pt | H2 | H+ half-cell is the cathode. Standard reduction potentials are given on the next page. (a) ...
Wednesday, November 28, 2012 at 9:27am

chemistry
15.00 ml of NaOH is obtained in an Erlenmeyer flask. Before titrating with .2500 M HCl, the initial volume of acid in a buret is read as 2.08 ml. At the endpoint the final volume of acid in the buret is 25.20 ml. What was the concentration of NaOH?
Wednesday, November 28, 2012 at 7:32am

CHEMISTRY
Ethylamine, CH3CH2NH2, is an organic base with pKb = 3.367 at 298 K. In an experiment, a 40.0 mL sample of 0.105 mol L-1 CH3CH2NH2 (aq) is titrated with 0.150 mol L-1 HI(aq) solution at 298 K. (a) Write a balanced chemical equation for the neutralization reaction upon which ...
Wednesday, November 28, 2012 at 1:08am

CHEMISTRY
A volume of 100ml of h20 is initially at room temperature (22.0c). A chilled steel rod at 2.00C is placed in the water. If the final temperature of the system is 21.2C , what is the mass of the steel bar?
Wednesday, November 28, 2012 at 12:54am

CHEMISTRY
Ethylamine, CH3CH2NH2, is an organic base with pKb = 3.367 at 298 K. In an experiment, a 40.0 mL sample of 0.105 mol L-1 CH3CH2NH2 (aq) is titrated with 0.150 mol L-1 HI(aq) solution at 298 K. (a) Write a balanced chemical equation for the neutralization reaction upon which ...
Wednesday, November 28, 2012 at 12:35am

Chemistry
What is the mass of a sample of material that has a volume of 51.1 cm3 and a density of 6.31 g/cm3?
Tuesday, November 27, 2012 at 11:21pm

CHEMISTRY
Suppose that you have 0.500 L of each of the following solutions, and an unlimited supply of water. (Note: C9H7NHBr is a salt containing the ions C9H7NH+ and Br− and C9H7N is quinoline, an organic base with pKb = 6.24 at 298 K. If you like, you may represent C9H7NH+ as ...
Tuesday, November 27, 2012 at 11:10pm

CHEMISTRY
Ethylamine, CH3CH2NH2, is an organic base with pKb = 3.367 at 298 K. In an experiment, a 40.0 mL sample of 0.105 mol L-1 CH3CH2NH2 (aq) is titrated with 0.150 mol L-1 HI(aq) solution at 298 K. (a) Write a balanced chemical equation for the neutralization reaction upon which ...
Tuesday, November 27, 2012 at 11:08pm

chemistry
intermolecular forces in caffeine
Tuesday, November 27, 2012 at 10:01pm

chemistry
Into a 1.00 liter flask are placed 0.820 moles of NO and 0.223 moles of N2 and O2. What are the concentrations of NO, N2, and O2 at equilibrium? For the molarity for each, I got this: NO= .027 M N2= .0079 M O2= .0069 M balanced equation: 2NO(g) <-> N2(g) + O2 How do I ...
Tuesday, November 27, 2012 at 10:00pm

Chemistry
Objectives To determine the molecular weight of a volatile liquid. Discussion [This laboratory exercise was adapted from one in Beran and Brady's Laboratory Manual for General Chemistry , John Wiley & Sons, 1982] The Dumas Method for determining the molecular weight of a ...
Tuesday, November 27, 2012 at 9:32pm

chemistry
how do i find the grams of potassium chloride per 100g of water in the saturated solution
Tuesday, November 27, 2012 at 9:27pm

chemistry
calculate number of dichlorine molecules in a 5.00ml container at 40 degrees Celsius and a pressure of 2.14 x 10^4 Pa.
Tuesday, November 27, 2012 at 9:24pm

chemistry
a saturated solution of barium chloride at 30 degrees Celsius contains 150 g water. how much addition barium chloride ca be dissolved by heating this solution to 60 degrees celsius? bacl2 at 30 degrees= 38.2 bacl2 at 60 degrees= 46.6
Tuesday, November 27, 2012 at 9:21pm

AP Chemistry
iron has a density of 7.86 g/cm3 and crystallizes a body centered cubic lattice. Show that only 68% of a body centered lattice is actually occupied by atoms, and determine the atomic radius of iron
Tuesday, November 27, 2012 at 8:40pm

Chemistry
3C3H8 + 20H2CrO4-> 9CO2 + 10Cr2O3 + 32H2O Suppose you want to make 1.50 g of chromium (III) oxide, how many ml of 6.25M chromic acid will you need to use if the percent yield of the reaction is 68.6%?
Tuesday, November 27, 2012 at 8:38pm

chemistry
how would you prepare 250 mL of a .1 M C12H22O11 starting with 2.5M C12H22O11
Tuesday, November 27, 2012 at 8:14pm

Chemistry
What is the general trend in the acidity of Period 3 oxides moving across the Periodic table from left to right? (Be sure to refer to the term acidity.)
Tuesday, November 27, 2012 at 7:02pm

Chemistry
Suppose I put 1 billion bacteria in a 10 ml tube of saline, mix well, and label this tube A. Answer the following questions: 1. Take 1 ml from tube A and put it in an empty tube B. What is the concentration and number of bacteria in tube B?
Tuesday, November 27, 2012 at 6:45pm

chemistry
a. Find the amount of solute based on this information Volume = 500 ml Concentration of solution= 15% (w/w) Solute (molar mass) = H2SO4 is 98.0g/mol b. Find the molar mass Amount of solute= 117.0g Volume of solution= 2.00L concentration of a solution= 1.0M volume of solvent = ...
Tuesday, November 27, 2012 at 6:16pm

Chemistry
Calculate the maximum mass of calcium metal that should be used in an equivalent mass determination, with a 100 ml gas measuring tube for collection. Assume 80 ml of hydrogen gas at standard conditions for the purposes of calculation.
Tuesday, November 27, 2012 at 4:45pm

chemistry
A 1.70 g sample of a certain metal reacts with acid to liberate 380 mL of hydrogen gas, when collected over water at 20 Celsius and over 720 torr. What is the equivalent mass of the metal?
Tuesday, November 27, 2012 at 4:43pm

chemistry
describe the preparation of 100ml of 6.0M HCl from a concentrated solution that has a specific gravity of 1.18 and is 37% w/w HCl.
Tuesday, November 27, 2012 at 3:53pm

chemistry
is water hard or soft if it contains 1.8 moles
Tuesday, November 27, 2012 at 2:56pm

chemistry
Balance the following equations. Show all work. MnO4- + Zn -> Mn2+ + Zn2+
Tuesday, November 27, 2012 at 2:53pm

College Chem 1
a chemistry handbook lists the solubility of NaI as 184 per 100mL of H2O at 25 degrees Celcius. 1) How many moles of NaI can be dissolved in 100mL of H2O at 25 degrees Celcius? 2) What would be the molarity of a saturated aqueous solution of NaI prepared at 25 degrees Celcius...
Tuesday, November 27, 2012 at 2:10pm

chemistry
An x-ray generator operated at a plate voltage of 7000 V is incapable of producing Ni Kα radiation. Calculate the minimum energy required for a ballistic electron to produce Ni Kα radiation. Express your answer in units of eV.
Tuesday, November 27, 2012 at 1:59pm

chemistry
What is Boyle's Law constant if a sealed rigid container with a volume of 650 mL has a pressure of 131.1 kPa ?
Tuesday, November 27, 2012 at 1:53pm

chemistry
Your x-ray lab has a monochromator consisting of a single crystal of nickel cut so that the (001) plane lies in the cube face. At what angle (in degrees) should the cube face be tilted with respect to the incident beam in order to select radiation with a wavelength λ=3....
Tuesday, November 27, 2012 at 1:44pm

Chemistry
How to predict the possible structures of a compound if the degree of unsaturation of it is in fraction?
Tuesday, November 27, 2012 at 1:24pm

chemistry
How would student make 500mL of .08500 M solution of iron using stock solution of .3180 M in iron(III)?
Tuesday, November 27, 2012 at 1:09pm

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