Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

chemistry (need by 5!!)
use the van der waals equation to calculate the pressure of 4.00 mol of H20 at 471K in a 4.60-L vessel. how do you solve?
Friday, April 26, 2013 at 4:33pm

chemistry
In a gas mixture, the partial pressures are argon 393 mm Hg, neon 73 mm Hg, and nitrogen 119 mm Hg. What is the total pressure (atm) exerted by the gas mixture?
Friday, April 26, 2013 at 3:57pm

Chemistry
How much ice (in grams) would have to melt to lower the temperature of 53.4g of water from 65 C to 0C? I know there are more than one step here, I would appreciate an answer that does not do the work for me, but show me how to lay out the problems and in which order... thank you!
Friday, April 26, 2013 at 3:15pm

organic chemistry isomers
which of the following molecules has a conformational isomer? CHCH CH2CH2 CH3CH2CH2CH3 CH2CCCH2 I think its either 2 or 4 but leaning towards 4. I just need help being more confident in my answer.
Friday, April 26, 2013 at 2:37pm

chemistry
Which of the following will increase the strength of a sample of 90% SiO2 - 10% MgO Quench the entire sample in water Quench half of the sample in water Cool the entire sample with air jets Cool half the sample with air Submerge the sample in a salt bath of Na2O Submerge the ...
Friday, April 26, 2013 at 2:09pm

chemistry
The energy of vacancy formation in palladium (Pd) is 1.5 eV. At 888C there is one vacancy for every million (106) atom sites. What temperature would be necessary to achieve a vacancy fraction of one for every thousand (10 3) atom sites? Express your answer in degrees C:
Friday, April 26, 2013 at 2:08pm

chemistry
The Young’s modulus for steel is 20.7*1010 N/m2. How much will a 2.5 mm diameter wire 12 cm long, be strained when it supports a load of 450 N? Aluminum’s Young’s modulus is 6.9*1010 N/m2. Express the strain as a decimal, not a percentage What diameter of ...
Friday, April 26, 2013 at 10:57am

chemistry
Acetaldehyde, CH3CHO, will decompose into methane and carbon monoxide according to CH3CHO (g) -> CH4 (g) + CO (g) At 450C the rate of consumption of CH3CHO is measured to vary with the concetration of CH3CHO raised to the power 1.5. With a CH3CHO concentration of 0.222M, ...
Friday, April 26, 2013 at 10:56am

chemistry
A specimen of LaNi5 containing hydrogen is placed in a vacuum furnace. After 1 hour, at what depth from the surface of the specimen has the concentration of hydrogen reached 1/3 the initial concentration? The diffusion coefficient of hydrogen in the alloy has a value of 3.091*...
Friday, April 26, 2013 at 10:55am

chemistry
To reduce the loss of helium, a pressure vessel is lined with a membrane made of tantalum. The concentration of helium at the inner surface of the membrane is held constant at 4.44*10-5 kg/m3, while the concentration at the outer surface of the membrane is held constant at ...
Friday, April 26, 2013 at 10:55am

chemistry
Glass A has a composition of 90% SiO2 - 10% Na2O. Glass B has a composition of 99% SiO2 - 1% Na2O. Both glasses are cooled to room temperature at the same rate. (a) Which glass has the higher Tg? Glass A Glass B (b) Which glass has the lower free volume?
Friday, April 26, 2013 at 10:53am

chemistry
Which of the following will increase the strength of a sample of 90% SiO2 - 10% MgO
Friday, April 26, 2013 at 10:53am

Chemistry
If 10.5 g of hydrogen, H2, were mixed with 6.51 g of acetylene, C2H2, and allowed to react according to the following equation, what is the theoretical yield of ethane, C2H6, produced? If 7.00 g of ethane, C2H6, were recovered at the end of the reaction, what is the percent ...
Friday, April 26, 2013 at 9:26am

'A'level chemistry
Plot a phase diagram of NaCl solution ,the minimum depression is 23 degrees celcious at concentration 5mol/dm-3. (I)concentration of NaCl(mol/dm-3) 0,6 ;1,2;2,2;3,5 freezing point depression (degrees celcious 2,0;4,0;8,0 ;14,0
Friday, April 26, 2013 at 5:14am

chemistry
The reaction x products follows Ist order kinetics in 40 minutes the concetration of x changes from 0.1M to 0.025M then the rate of reaction when conc of x is 0.01
Friday, April 26, 2013 at 5:04am

Chemistry
Calculate the density of atoms on plane (001) in Lithium
Friday, April 26, 2013 at 2:25am

chemistry
N-type silicon (Si) has been produced by doping with phosphorus (P). The charge-carrier population based on electrical conductivity measurments is determined to be 3.091*1017 carriers/cm3 at room temperature. Calculate the doping level of P (how much P has been added to the Si...
Friday, April 26, 2013 at 2:16am

Chemistry
Calculate the density of atoms in (001) in lithium (Li)(units of atoms/cm2)
Friday, April 26, 2013 at 2:16am

chemistry
Consider an x-ray tube with a Cu anode and a monochromator consisting of a nickel single crystal with (111) planes parallel to the surface of the crystal. What is the lowest voltage capable of producing x-rays through a monochromator? Express your answer in V:
Friday, April 26, 2013 at 2:15am

chemistry
A sample of molybdenum (Mo) is analyzed by x-ray diffraction using NiK radiation. Calculate the value of the angle at which the lowest-angle reflection is observed. Express your answer in degrees:
Friday, April 26, 2013 at 2:15am

chemistry
A chemical analysis indicates that a silicon crystal weighing 100g contains 16.5 mg of aluminum (Al) which is substitution-ally incorporated (the Al atoms replace some of the Si atoms). What is the number of extrinsic charge carriers in this crystal? Express your answer as ...
Friday, April 26, 2013 at 2:10am

Chemistry
Calculate the molar solubility of MgCO3 in a solution that already contains 1.7×10−3 M sodium carbonate. MgCO3 Ksp = 6.82 x 10-6 IMPORTANT NOTE: You must use the quadratic equation to solve this problem. (DrBob222- thank you so much for all your help!)
Friday, April 26, 2013 at 1:54am

chemistry
Calculate the density of atoms in (001) in lithium. Express answer in atoms/cm.
Friday, April 26, 2013 at 1:29am

Chemistry
Lithium metal is a highly reactive metal that oxidizes instantly in water or air. Given the data below, calculate the energy required to heat 10.0 g of Li from 150.0 °C to 200.0 °C. Molar heat capacity (solid) = 3.58 J/°C • mol Molar heat capacity (liquid) = 4...
Thursday, April 25, 2013 at 11:53pm

Chemistry
Ethanol (C2H5OH) has been produced since antiquity by the fermentation of fruits and vegetables. Given the following data, if 5.87 kJ of energy are transferred to 13.3 g of frozen ethanol at -130.0 °C, what is the final temperature of the sample? Heat capacity (solid) = 0....
Thursday, April 25, 2013 at 11:52pm

chemistry
Given the thermochemical equation below, calculate the amount of energy released when 250. g of NaOH (molar mass = 40.0 g/mol) reacts with an excess of HCl. Report answer to the correct number of significant figures in units of kilojoules, kJ. NaOH + HCl --> NaCl + H2O ...
Thursday, April 25, 2013 at 9:31pm

Chemistry
What concentration of SO32– is in equilibrium with Ag2SO3(s) and 3.60 × 10-3 M Ag ? The Ksp is 8.46×10–12.
Thursday, April 25, 2013 at 9:05pm

Chemistry
What concentration of SO32– is in equilibrium with Ag2SO3(s) and 3.60 × 10-3 M Ag ? The Ksp is 8.46×10–12.
Thursday, April 25, 2013 at 9:04pm

Chemistry
Calculate the pH for each of the following cases in the titration of 50.0 mL of 0.140 M HClO(aq) with 0.140 M KOH(aq).HClO is a weak acid with a Ka of 4.0× 10–8. It reacts with strong base to produce ClO–. (e) after addition of 60.0 mL of KOH
Thursday, April 25, 2013 at 9:03pm

Chemistry
What concentration of SO32– is in equilibrium with Ag2SO3(s) and 3.60 × 10-3 M Ag ? The Ksp is 8.46×10–12.
Thursday, April 25, 2013 at 9:02pm

chemistry
At 25 °C only 0.0390 mol of the generic salt AB3 is soluble in 1.00 L of water. What is the Ksp of the salt at 25 °C?
Thursday, April 25, 2013 at 8:38pm

Chemistry
Calculate the H3O concentration if 100.0 ml of the .10M HNO3 solution is diluted to 1.0L with water?
Thursday, April 25, 2013 at 8:03pm

Chemistry
Estimate the fraction of of unoccupied atomic sites in lead (Pb) at a temperature 10K below its melting point. DATA: Vacancy Fraction, nv/N T (degrees C) 1.8*10^-7 100 7.2*10^-6 200 Express your answer in terms of vacancy fraction, nv/N:
Thursday, April 25, 2013 at 7:18pm

Chemistry
A sample of molybdenum (Mo) is analyzed by x-ray diffraction using NiKα radiation. Calculate the value of the angle at which the lowest-angle reflection is observed. Express your answer in degrees:
Thursday, April 25, 2013 at 7:17pm

Chemistry
N-type silicon (Si) has been produced by doping with phosphorus (P). The charge-carrier population based on electrical conductivity measurments is determined to be 3.091*10^17 carriers/cm3 at room temperature. 1. Calculate the doping level of P (how much P has been added to ...
Thursday, April 25, 2013 at 7:15pm

chemistry
how many moles of gold are there in 1.00 L of seawater if there are 1.50^17 atoms of gold in the sample?
Thursday, April 25, 2013 at 6:19pm

Chemistry
A mass of a copper oxide weighed 10.00grams. The reaction was run and the amount of just copper obtained was 8.88grams. What is the empirical formula of the compound?
Thursday, April 25, 2013 at 6:12pm

Chemistry
Solution A is 2.40M. 20mLs of solution A is transferred to a 250mL volumetric flask and diliuted to volume with water. What is the concentration of the diluted solution?
Thursday, April 25, 2013 at 6:10pm

Chemistry
Calculate the concentration of bromocresol green (BG) indicator It says that Molar absorptivity = Absorbance at a wavelength/ concentration of BG indicator I am having trouble calculating the concentration of BG. Other info: Stock solution of BG = 80.0 mg/L and molar mass = ...
Thursday, April 25, 2013 at 5:59pm

chemistry
calculate the hydroxide ion concentration in a solution of almond extract PH.3.8.state if almond is basic or acid
Thursday, April 25, 2013 at 4:26pm

chemistry
A 45 g block of aluminum initially at 28.0° C absorbs 548 J of heat. What is the final temperature of the aluminum? The specific heat of aluminum is 0.902 J/g °C.
Thursday, April 25, 2013 at 1:35pm

chemistry
A 13.8 g piece of Zn metal was heated to 98.6 oC and then dropped in 45.6 g of water at 25.0 oC. Assuming that no heat is lost to the surroundings, determine the specific heat capacity of Zn if the final temperature of the water was 27.1 oC C=6461.39
Thursday, April 25, 2013 at 1:33pm

chemistry
a sample of argon gas at standard pressure ocupies 100ml. at constant temp, what volume does the gas occupy if the temp increases to 800mmHg
Thursday, April 25, 2013 at 1:01pm

A.P. Chemistry
Thorium-232 undergoes alpha decay and has a half-life of 1.4 * 10^10 years. How long will it take for a 1.00mg sample of thorium-232 to be reduced to 0.5mg?
Thursday, April 25, 2013 at 11:38am

chemistry
the amount of K2Cr2O7 required to prepare 100ml of its 0.05N solution
Thursday, April 25, 2013 at 3:24am

chemistry
A compound was found to be composed of the following amounts of elements: 20.00% wt% C, 26.64wt% O, 46.65 wt%N, and 6.71wt%H. A 6.125 grams sample of this compound dissolved in 46.205 grams of water as a solution was found to have a freezing point of -3.260C. The density of ...
Thursday, April 25, 2013 at 2:04am

chemistry
To treat a burn on your hand, you decide to place an ice cube on the burned skin. The mass of the ice cube is 16.0 g, and its initial temperature is -10.4 °C. The water resulting from the melted ice reaches the temperature of your skin, 28.3 °C. How much heat is ...
Thursday, April 25, 2013 at 12:32am

Chemistry
Balance the following redox reaction and identify the oxidizing and reducing agents A- Fe2+(aq) + Cr2072-(aq) -->Fe3+(aq) + Cr3+(aq) (acidic) B- N2H4(g) + ClO3-(aq) -->NO2(g) + Cl- (basic)
Thursday, April 25, 2013 at 12:12am

chemistry
Calculate the molar solubility of silver chloride (AgCl) in: a-deionized water and b-.20M NaCl solution Given Ksp=1.6*10^-10 please show work.
Thursday, April 25, 2013 at 12:04am

Chemistry- Acid-base titration
The indicated endpoint of an acid-base titration seldom occurs at a ph of 7. what determines the ph of the endpoint??
Wednesday, April 24, 2013 at 11:09pm

Chemistry
What is the pH of a solution of 40.0 ml of 0.800 M HCl titrated with 4.00 ml of 1.00 M Hydroxyl amine?
Wednesday, April 24, 2013 at 10:43pm

Chemistry
0.356 grams of an unknown metal reacts with oxygen to form 452 milligrams of the metal oxide. Identify the metal
Wednesday, April 24, 2013 at 10:42pm

Chemistry
If 10.5 g of hydrogen, H2, were mixed with 6.51 g of acetylene, C2H2, and allowed to react according to the following equation, what is the theoretical yield of ethane,C2H6 produced? If 7.00g of ethane, C2H6 were recovered at the end of the reaction , what is the percent yield...
Wednesday, April 24, 2013 at 10:03pm

Chemistry
If 10.5 g of hydrogen, H2, were mixed with 6.51 g of acetylene, C2H2, and allowed to react according to the following equation, what is the theoretical yield of ethane,C2H6 produced.
Wednesday, April 24, 2013 at 9:56pm

Chemistry
In the qualitative analysis scheme, what qualitative analysis principles are used to seperate Cu2+ from Al3+? Check all that apply. -Selective precipitation -Fractional precipitation -Amphoteric precipitate solubilization -Competitive equilibrium solubilization: anoion ...
Wednesday, April 24, 2013 at 9:51pm

math
A textbook store sold a combined total of 462 biology and chemistry textbooks in a week. The number of biology textbooks sold was two times the number of chemistry textbooks sold. How many textbooks of each type were sold?
Wednesday, April 24, 2013 at 9:38pm

chemistry
the pressure in a 1.0 container is 988 ATM what is the pressure in a 2.56L container? ( use gas laws )
Wednesday, April 24, 2013 at 9:18pm

chemistry
platinum metal currently costs $1700 per troy ounce ( note: this is different than a regular ounce 1 troy ounce =31.1035 g. what would the costs be, in dollars , to purchase enough platinum to form a solid cone with maximum radius 0.750 m ?
Wednesday, April 24, 2013 at 8:59pm

Organic Chemistry
How do I make an IR Spectrum of C6H12S2 (Allyl Propyl Disulfide)
Wednesday, April 24, 2013 at 8:18pm

chemistry
When sulphur dioxide is dissolved in water and a drop of Universal Indicator was added the indicator, what colour would the indicator turn ?
Wednesday, April 24, 2013 at 5:28pm

chemistry
A 33.0g sample of nitrogen, N2 has a volume of 42.0L and a pressure of 640.mmHg. What is the temperature, in kelvins and degrees Celsius, of the gas?
Wednesday, April 24, 2013 at 4:05pm

Chemistry
Draw the Lewis dot diagram of CO2, how many types of electrons are in the valence bond?
Wednesday, April 24, 2013 at 3:52pm

Chemistry
The Fe3+ ion has electronic configuration of d5. if all five electrons are unpaired. what is the spin state? (a) singlet (b) sextet (c)septet (d)Octet (e) none of the above the answer is____ Also Which of the following 1H are most deshielded relative to the TMS standard at 0 ...
Wednesday, April 24, 2013 at 3:02pm

chemistry
Part A Identify the anode and cathode, and indicate the direction of Na+ ion and NO3 - ion flow from the salt bridge. 1) Al is the anode and Co is the cathode; Na+ ions flow into half-cell compartment (A) and NO3 - ions flow into half-cell compartment (B). 2) Co is the anode ...
Wednesday, April 24, 2013 at 2:41pm

Chemistry
What is the amount of work produced when 1.0 g of H2O (l) is boiled at atmospheric pressure? Assume the liquid has no volume.
Wednesday, April 24, 2013 at 2:31pm

chemistry
A sample of copper metal containing 7.738*10^24 atoms is drawn into a cylindrical wire with radius r = 0.625 mm . How long must the wire be in meters?
Wednesday, April 24, 2013 at 2:20pm

chemistry
calculating the molarity of acetic acid in a vinegar sample given that 5.00 of vinegar required 43.50 mL of 0.1050 M NaOH to just reach the methyl red endpoint.
Wednesday, April 24, 2013 at 11:40am

chemistry
interpret the following balanced equation into Particles, Moles, Mass: 2Al+3CuSO4== AL2(SO4)3+ 3Cu
Wednesday, April 24, 2013 at 10:59am

Chemistry
Why is it necessary to use a buret for measuring standard silver nitrate solutio ( volhard)
Wednesday, April 24, 2013 at 7:05am

Chemistry
how did you get (that's 0.17M x 1/2 = 0.085M)
Wednesday, April 24, 2013 at 1:02am

Chemistry
What is the ph at the equivalence point for a titration of 250 mL of 0.17M piperidine with 0.17 M nitric acid. (piperidine: Kb = 1.3 x 10-3)
Tuesday, April 23, 2013 at 11:30pm

chemistry
What is the final temperature of 1370 g of water, originally at 20.9°C, if it absorbs 47.6 kJ of heat?
Tuesday, April 23, 2013 at 11:11pm

Chemistry
3. Using Bohr’s model of the atom, calculate the energy required to move an electron from a ground state of n = 2 to an excited state of n = 3. Express your answer in both J/photon and kJ/mol.
Tuesday, April 23, 2013 at 10:26pm

Chemistry
how many joules and calories are produced from the reaction CaCl2+H2O=HCl+CaOH
Tuesday, April 23, 2013 at 10:14pm

chemistry
concentrated sulfuric acid is typically 18.1 M H2 SO4. Calculate the volume in mL of concentrated sulfuric acid needed to prepare 125 mL of a 0.100 M H2SO 4 solution
Tuesday, April 23, 2013 at 9:49pm

chemistry
how many liters are occupied by 0.908 mol of nitrogen at 108 degrees C and 0.858 atm pressure?
Tuesday, April 23, 2013 at 9:29pm

Chemistry
What is the pH of a solution that is 0.0100 M in HCN and 0.0200 M in NaCN?
Tuesday, April 23, 2013 at 9:15pm

chemistry
which melts at a low temp in a solid nonelectrolyte what type of solid is it
Tuesday, April 23, 2013 at 9:09pm

Chemistry - Urgent Please help!!
The problems: 0.0513 grams of Al (Wt. 27.0) was reacted with excess HCI to produce H2 according to the following balanced equation: 2 Al + 6 HCI ---> 2 AlCl3 + 3 H2 a) Determine the number of moles of H2 evolved from that quantity of Al when collected over water? 0.0513g Al...
Tuesday, April 23, 2013 at 7:01pm

Chemistry 12
Determine the molar solubility of lead(II) iodide, PbI2, in 0.050 mol/L NaI. Ksp of PbI2 = 9.8 x 10^(-9)
Tuesday, April 23, 2013 at 6:43pm

Chemistry
The question is: What is the molarity of the copper (II) chloride solution your teacher provided? Show calculations. Obtain the true molarity of the copper (II) chloride solution and calculate percent error. I have done this so far trying to answer the question: Molar Mass: (...
Tuesday, April 23, 2013 at 6:20pm

chemistry
When totally digested by acid and rocessed into a sample of one liter solution volume for spectroscopy, a 3.21 gram sample of alloy yeilded an absorbance of 0.288. Calculate the percent by wieght of iron in the alloy sample
Tuesday, April 23, 2013 at 5:58pm

CHEMISTRY
You carry out a reaction with 28.9mL of 0.711M solution of NiNO3)2. The reaction has a change in H of -26.4KJ/mol rxn. What is the q, the heat of the reaction, in joules? I first found the mols of the solution using molarity and then found the joules of the reaction through ...
Tuesday, April 23, 2013 at 4:59pm

Chemistry
Galena(PbS) and cerussite(PbCO3)are two ores of lead. A mining company is considering which of these two ores to use for the extraction of lead. The equations for the reactions occurring are process using galena: 2PbS+3O2 ---> 2PbO+2SO2 2PbO+C ----> 2Pb+CO2 Process using...
Tuesday, April 23, 2013 at 1:21pm

chemistry
How would you figure: How much energy, in kJ, is absorbed by 23.8 g of acetone when it evaporates if its molar heat of vaporization is 32.0 kJ/mol? Acetone formula is C3H6O
Tuesday, April 23, 2013 at 12:53pm

chemistry
In a bottle of unopened cola, the CO2 dissolved in the liquid is in equilibrium with the CO2 gas above the liquid. The dissolved gas reacts with water molecules in the liquid to from carbonic acid, which also dissociates into carbon dioxide and water. Which chemical equation(s...
Tuesday, April 23, 2013 at 12:05pm

Chemistry
Consider the titration of 41.2ml of 0.230 M HF with 0.220 M NaOH . Calculate the ph after the addition of 11.9ml of sodium hydroxide.(HF: Ka = 3.50 x 10-4) Please, I need step by step on on how to solve this type of problem. Thank you very much!
Tuesday, April 23, 2013 at 1:22am

CHEMISTRY
Suppose a student adds 25.00 mL of 1.025 M HCl to a 1.50 g antacid tablet. The student boils and then titrates the resulting solution to the endpoint with 0.4969 M NaOH. The titration requires 21.3 mL NaOH to reach the endpoint. How many moles of HCl were neutralized by the ...
Tuesday, April 23, 2013 at 12:40am

chemistry FP depression
if I had to choose a solvent for a freezing point depression lab...would I choose Chloroform or Benzophenone? and why?
Tuesday, April 23, 2013 at 12:21am

chemistry
if calculating molecular weight of unknown by freezing point depression...All of the unknowns in the activity were nonpolar organic molecules with molecular weight= 100-250 g/mol and using around 1g of the unknown. Provide an example of a solvent that could possibly be used ...
Monday, April 22, 2013 at 11:50pm

CHEMISTRY URGENT!
alpha emission by plutonium 242 write a nuclear equation
Monday, April 22, 2013 at 11:39pm

Chemistry
Net Ionic Equation for reaction between bromide and silver nitrate
Monday, April 22, 2013 at 9:00pm

chemistry/Ksp
It is more accurate to report a single value OR a range of values for Ksp?
Monday, April 22, 2013 at 8:57pm

CHEMISTRY
What mass of NaCl is required to precipitate all the Ag ions from 20 mL of .100 M AgNO3 solution
Monday, April 22, 2013 at 6:35pm

Chemistry
If the hydrogen volume reads 8.35 mL, what number of moles does the represent at STP (1 atm and 0oC)? How many moles of electrons were added to the solution to create 8.35 mL of hydrogen gas?
Monday, April 22, 2013 at 6:17pm

analytical chemistry
chemical equilibria involved in precipitation reaction
Monday, April 22, 2013 at 6:13pm

Chemistry!!
A chemist wants to prepare a stock solution of H2SO4 so that a sample of 20.00mL will produce a solution with a concentration of .50 M when added to 100.0mL of water. A)what should the molarity of the stock solution be? B)If the chemist wants to prepare 5.00L of the stock ...
Monday, April 22, 2013 at 6:09pm

chemistry
how many moles of sand were reacted when you process 100 g of sand and produce 51.4 g of silicon carbide
Monday, April 22, 2013 at 5:59pm

CHEMISTRY
If a tablet contains 129 mg of Mg(OH)2 and 505 mg of CaCO3, how many moles of HCl would theoretically be neutralized?
Monday, April 22, 2013 at 5:52pm

Chemistry
The equation for the reaction that occurs when lead(II) oxide is heated with coke in a blast furnace is: 2PbO+c -->2Pb+CO2 (i)State, with a reason, whether PbO is oxidised or reduced in this reaction. (ii)Calculate the minimum mass, in tonnes, of coke needed to react with ...
Monday, April 22, 2013 at 2:51pm

Chemistry
Lead can be extracted from lead(II) sulfide, PbS, in two stages. Stage 1: Lead(II) sulfide is heated in air. It reacts with oxygen to produce lead(II) oxide and sulfur dioxide. Stage 2: The Lead(II) oxide is then heated in a blast furnace with coke. (a) Write a chemical ...
Monday, April 22, 2013 at 2:37pm

Chemistry 110, college
A solution is prepared by dissolving 56.5g of ethylene glycol in 874 g of water. Calculate the change in the boiling point and the freezing point.
Monday, April 22, 2013 at 2:05pm

chemistry
What is the osmotic pressure in torr of a 0.0155 M glucose solution at body temperature ( 35.7 °C)? What are the boiling and freezing points for the same solution?
Monday, April 22, 2013 at 1:01pm

chemistry
how many milliliter of .750M sulfuric acid are needed to neutralize completely 20 g of NaOH?
Monday, April 22, 2013 at 12:04pm

chemistry
if burning one mole releases 1310.0 kj, then how many moles will release 227.30?
Monday, April 22, 2013 at 11:44am

Chemistry
Suppose you wanted to find out how many milliliters of 1.0 M AgNO3 are needed to provide 169.88 g of pure AgNO3. a. What is step 1 in solving the problem? b. What is the molar mass of AgNO3? c. How many milliliters of solution are needed?
Monday, April 22, 2013 at 11:26am

Chemistry
How much energy, in kj, is absorbed by 23.8g of acetone when it evaporates if its molar heat of vaporization is 32.0 kj/mol?
Monday, April 22, 2013 at 9:33am

chemistry
is there a chemical equation for gadolinium medium contrast?
Monday, April 22, 2013 at 9:11am

chemistry
For each of the following primary standard acids, write the titration equation and calculate the volume of 0.100 M NaOH required for the titration: (i) 300 mg benzoic acid (C6H5COOH) (ii) 200 mg oxalic acid dihydrate (C2O4H2.2H2O) Equations: (i): C6H5COOH +NaOH->NaC6H5COO +...
Monday, April 22, 2013 at 6:45am

chemistry
Calculate the weight (in mg) of borax Na2B4O7.10H20 required to react with 25.0 mL if 0.100 M HCI No. moles HCl consumed = __________ moles No. moles borax required = __________ moles Molar mass of borax = __________ g mol-1 (Na2B4O7.10H2O) Weight borax required = __________ g...
Monday, April 22, 2013 at 6:04am

chemistry
15.0 mL of 8.00 M NaOH was diluted with water to 500 mL. Calculate the molarity of the diluted NaOH solution. My calculations: 0.015L x 8.00moles/1L x 39.997/1mole = 4.8g M= (4.8g x 1mole/39.997) / 0.500L = 0.24M is my workings correct? Is there another way to get to this?
Monday, April 22, 2013 at 5:55am

chemistry
STANDARDISATION OF 0.1 M HCl Borax dissolves slowly in water at room temperature. Why do we not use a stirring rod to mix the solution and speed up this stage of the experiment?
Monday, April 22, 2013 at 5:01am

Chemistry
25 mL 0.1 M acetic acid is titrated with 0.1 M NaOH. Calculate the pH after the addition of 0.0 mL, 1.0 ml, 2.5 mL, 4.0 mL, 7.0 mL, 10.5 mL, 15.0 mL, 17.0 mL, 20.0 mL, 22.0 mL, 23.0 mL, 23.5 mL, 24.0 mL, 24.25 mL, 24.5 mL, 24.75 mL, 25.0 mL, 25.25 mL, 25.5 mL, 25.75 mL, 26.0 ...
Monday, April 22, 2013 at 4:34am

Chemistry
Need type of reaction and balance of (NH4)2S+CuSO4=
Monday, April 22, 2013 at 3:07am

Chemistry
(NH4)2S+CuSO4=
Monday, April 22, 2013 at 3:06am

chemistry
Using the PM3 semiempirical method in HyperChem, treat planar napthalene. First build the molecule, choose SemiEmpirical methods and PM3, and perform a Geometry Optimization. Look in the "Compute>Orbitals" menu to determine the energies of the HOMO and LUMO. What ...
Monday, April 22, 2013 at 2:55am

Organic Chemistry
A student dehydrated 12 grams of 2-methylcyclohexene with 85% H3PO4, and acquired 6.50 grams of alkene. What are the theoretical and percent yields?
Monday, April 22, 2013 at 2:32am

Organic Chemistry
A student dehydrated 12 grams of 2-methylcyclohexene with 85% H3PO4. What are the theoretical and percent yields?
Monday, April 22, 2013 at 2:28am

Organic Chemistry
A student dehydrated 12 grams of 2-methylcyclohexene with 85% H3PO4. What are the theoretical and percent yields?
Monday, April 22, 2013 at 2:27am

chemistry
predict which three of the following five aqueous solutions should react with solid aluminum metal (the elemental form of aluminum): AgNO3, Na2CO3, CuSO4, CaCl2, Pb(NO3)2
Monday, April 22, 2013 at 1:25am

Chemistry
I had to share a diagnostic procedure that I had done. I shared a breast MRI, in which I had contrast. Now I need to share on balanced chemcial equation related to this, and be sure to be specific. Can someone please help me??
Monday, April 22, 2013 at 12:47am

chemistry
Determine how much of each product (in g or L) is formed. 2.50g of aluminum metal is placed in a large container of concentrated copper (ll) suflate to produce copper metal.
Sunday, April 21, 2013 at 11:50pm

chemistry
A 32.0-g sample of water at 290. K is mixed with 51.0 g water at 310. K. Calculate the final temperature of the mixture assuming no heat loss to the surroundings.
Sunday, April 21, 2013 at 10:55pm

chemistry
Identify the limiting reagent. 2.43g of magnesium is added to a solution containing 0.100 mol hydrochloric acid t ok produce hydrogen gas.
Sunday, April 21, 2013 at 10:14pm

Chemistry
calculate the ph 25.00 mL solution of 0.125 M acetic acid (Ka= 1.75 x 10^-5) after the addition of each of the following volumes of 0.100 M KOH: 10.00 mL, Vep and 35.00 mL
Sunday, April 21, 2013 at 9:25pm

General Chemistry
"How would you prepare 150. mL of 0.1M sodium hydroxide given a stock solution of 3.0M NaOH?" I made calculations and figured the process would be to dilute 5 mL of the 3.0M NaOH to 150. mL. Is this correct? For the ideal 150. mL of 0.1M NaOH, I calculated there to ...
Sunday, April 21, 2013 at 9:18pm

chemistry
If 10.4 liters of O2 at STP are produced by the electrolysis of water, how many coulombs of charge were required?
Sunday, April 21, 2013 at 8:42pm

chemistry
what will be the internal pressure causes by hydrogen gas when 5.00 g of zinc is dissolved in 50 g of concentrated hydrochloric acid if the volume of the container is 250 mL and the container is allowed to cool 20 degrees celcius
Sunday, April 21, 2013 at 8:34pm

Chemistry
What are the Six possible ratios for the equation for the formation of potassium chloride?
Sunday, April 21, 2013 at 8:02pm

Chemistry
What are the Six possible ratios for the equation for the formation of potassium chloride?
Sunday, April 21, 2013 at 8:00pm

Chemistry
Find the entropy change of the universe when 2 moles of water freezes at -10 degrees celsius. The delta G for the freezing of water at -10 degrees celsius is -210 J/mol and the heat of fusion of ice at this temperature is 5610 J/mol.
Sunday, April 21, 2013 at 7:02pm

Chemistry
Find the entropy change of the universe when 2 mol of water freezes at -10 degrees celsius.
Sunday, April 21, 2013 at 6:35pm

Chemistry
A solution contains 0.022 M Ag and 0.033 M Pb2 . If you add Cl–, AgCl and PbCl2 will begin to precipitate. What is the concentration of Cl– required, in molarity, when A. AgCl precipitation begins? B. AgCl precipitation is 99.99% complete? C. PbCl2 precipitation ...
Sunday, April 21, 2013 at 6:10pm

Chemistry
What [PB2+] should be maintained in Pb(NO3) to produce solubility of 1.0*10^-4 mol PbI2/L when PbI2 (s) is added? Ksp for PbI2 is 7.1*10^-9 I can't figure it out...
Sunday, April 21, 2013 at 5:44pm

Chemistry
Write an equation that represents how dihydrogen phosphate ion (H2PO4-) behaves as an Arrhenius acid. ( Be sure to include the correct charges for ions.)
Sunday, April 21, 2013 at 5:09pm

Chemistry
Write an equation showing that calcium hydroxide acts as an Arrhenius base in water. **(I'm not sure where to start or how to go about this question)
Sunday, April 21, 2013 at 2:55pm

Chemistry
Write the product for the reaction when dichlorine oxide (Cl_2O) reacts with water (the product will have only one equivalent of chlorine in it).
Sunday, April 21, 2013 at 2:26pm

Chemistry
Assume you dissolve 0.235 g of the weak acid benzoic acid, C6H5CO2H, in enough water to make 4.00*10^2 mL of solution and then titrate the solution with 0.138 M NaOH. C6H5CO2H(aq) + OH-(aq) C6H5CO2-(aq) + H2O(l) Find concentration of Na+ at equivalence point.
Sunday, April 21, 2013 at 1:52pm

Chemistry
Calculate the H3O+ ion concentration and the pH at the equivalence point when 45.0 mL of 0.4000 M NH3 is mixed with 45.0 mL of 0.4000 M HCl. Ka=5.6x10-10
Sunday, April 21, 2013 at 1:40pm

chemistry
what is the h+ of a solution with a ph of 10 at 25 degree celsius
Sunday, April 21, 2013 at 1:12pm

AP chemistry
A concentration cell consists of the same re- dox couples at the anode and the cathode, with different concentrations of the ions in the respective compartments. Find the un- known concentration for the following cell. Pb(s) | Pb2+(aq, ?) || Pb2+(aq, 0.1 M) | Pb(s) Answer in ...
Sunday, April 21, 2013 at 1:00pm

chemistry
in relation to the pH of pure water at 25 degree Celsius where do the pH values of acid fall
Sunday, April 21, 2013 at 12:44pm

Chemistry
A concentration cell consists of the same re- dox couples at the anode and the cathode, with different concentrations of the ions in the respective compartments. Find the un- known concentration for the following cell. Pb(s) | Pb2+(aq, ?) || Pb2+(aq, 0.1 M) | Pb(s) Answer in ...
Sunday, April 21, 2013 at 12:23pm

Chemistry
Please help!:( What mass of copper would be produced by the reduction of copper(II) ions during pas- sage of 1 ampere of current through a solution of copper(II) sulfate for 89 minutes?
Sunday, April 21, 2013 at 12:20pm

organic chemisty
write raction of benzoic acid with propylamine
Sunday, April 21, 2013 at 10:05am

chemistry
A 2.5 g sample of NaOH (Mw = 40.00) was dissolved in water to give a solution of final volume 250 cm3. (i) With reasons, state whether NaOH is a strong or a weak base. Give the conjugate acid of NaOH and decide whether this conjugate acid is acid, alkaline or neutral. (ii) ...
Sunday, April 21, 2013 at 10:01am

Chemistry
what happens to a battery when it is "recharged"
Sunday, April 21, 2013 at 2:31am

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