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October 23, 2014

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

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Chemistry
How to make 0.086M sodium phosphate when combined with 0.1N HCl has a pH of 6.2?
Wednesday, August 27, 2014 at 8:48am

Chemistry
How much water must be added to 963 g of solid sodium hydroxide needed in order to prepare a 1.50 M solution?
Wednesday, August 27, 2014 at 1:37am

Chemistry
a cap cork stopper from a bottle of liquid is not put down on a desk while you are pouring out some of the liquid why?
Tuesday, August 26, 2014 at 9:14pm

chemistry
glycine and lysine, have the following values of the relevant acid dissociation constants (pKa) glycine, pKa=2.35 lysine,pKa=10.79 For an aqueous solution of glycine alone, calculate the value of pH at which the ratio of the concentration of neutral glycine zwitterions to the ...
Tuesday, August 26, 2014 at 9:10pm

Chemistry
What procedures should you follow to:: 1. report spilling a chemical or breaking equipment? 2. cope with a fire on your lavatory bench? 3. dispose of cracked or broken glassware?
Tuesday, August 26, 2014 at 8:43pm

Chemistry
Why should you use only clean glassware?
Tuesday, August 26, 2014 at 8:31pm

Chemistry Help!!!!!!!!!!!!!!
for the following elements show the allocation of electrons to their orbitals on the basis of the Pauli exclusion principle and Hund's rule. a) Carbon b) Silicon Thanks!
Tuesday, August 26, 2014 at 6:31pm

chemistry
A 1.11 M solution of fluoroacetic acid, FCH2CO2H, is 5% dissociated in water. Calculate the value of the pKa of FCH2CO2H. pKa: ?? I dn't even know how to strt with this
Tuesday, August 26, 2014 at 6:25pm

chemistry
the boiling point increased by 2oC, what is the approximate molality of NaCl. K boiling point(water)= 0.512oC/m
Tuesday, August 26, 2014 at 6:12pm

chemistry
the density of alcohol is 0.79g/ml. find the mass of 15.5ml of alcohol? 15.5ml x 0.79g/ml = mass 12.245g
Tuesday, August 26, 2014 at 5:52pm

chemistry
the freezing point of benzene C6H6 is 5.5000C at 1 atmosphere. In a laboratory experiment, students synthesized a new compound and found that when 10.70 grams of the compound were dissolved in 294.0 grams of benzene, the solution began to freeze at 4.9740C. The compound was ...
Tuesday, August 26, 2014 at 5:41pm

chemistry
pepsin is an enzyme involved in the process of digestion. its molar mass is about 3.50 x 10^-4 g/mol. what is thr osmotic pressure in mm Hg at 30 degree oC of a 0.400g sample of pepsin in 55.0mL of an aqueous solution?
Tuesday, August 26, 2014 at 4:53pm

Chemistry
The relative molecular mass of a molecule of chlorine is 72. Which properties of the atoms in this molecule are the same? 1 radius 2 nucleon number 3 relative isotopic mass Answer: 1 only Can someone please explainnn! Thanks :)
Tuesday, August 26, 2014 at 10:47am

chemistry
The vapor pressure of ethanol is 54.68 mm Hg at 25oC. How many grams of chlorophyll , C55H72MgN4O5, a nonvolatile, nonelectrolyte (MW = 893.5 g/mol), must be added to 207.6 grams of ethanol to reduce the vapor pressure to 53.60 mm Hg ? ethanol = CH3CH2OH = 46.07 g/mol.
Tuesday, August 26, 2014 at 9:45am

Analytical Chemistry
A 500-mL buffer was prepared and it is 0.300 M in nitrous acid (HNO2 , Ka = 4.0 x 10-4) and 0.200 M in sodium nitrite, NaNO2. What will be the pH of this solution after adding 1.00 mL of 6.00 M HCl?
Tuesday, August 26, 2014 at 8:14am

chemistry
a solution is prepared by mixing 1.0 grams of benzen(c6h6) in 100g of water to create a solution total volume of 100ml.calculate the molarity,mass percent,mole fraction and molarity of benzene in the solution
Tuesday, August 26, 2014 at 4:11am

chemistry
At what angle (in degrees) must {111} planes of platinum (Pt) be exposed to a collimated beam of thee X-rays in order to obtain by diffraction monochromatic CrKα radiation.
Tuesday, August 26, 2014 at 2:14am

High School Chemistry
How many kilograms of salt water, (with a density of 1.20 g/cm^3) are needed to fill an aquarium that measures 125.0 ft^3? (Hint: Density can be used as a conversion factor to convert volume to mass.)(Remember to make use of significant figures.) I haven't the slightest ...
Tuesday, August 26, 2014 at 1:57am

Chemistry
Determine for solid manganese (Mn) the following: What is the atomic density (atoms/m) along the [110] direction of the Mn crystal? What are the number of nearest neighbors around an atom in the Mn crystal? Calculate the interplanar spacing (m) between {220} planes in the Mn ...
Tuesday, August 26, 2014 at 12:54am

chemistry
Gallium Arsenide ---------------- The charge carrier density of GaAs at 31o C is 2.25x106 cm-3. What is the charge carrier density (in cm-3) at 175oC? (The bandgap of GaAs is 1.42 eV. ) I am trying with arrhenius relationship but get confused over "charge carrier density&...
Monday, August 25, 2014 at 9:50pm

ap chemistry
A powder has a mass of 40.0g. When the powder is added to 30.0mL of water, the total volume is 45.0mL. What is the density of the powder
Monday, August 25, 2014 at 9:47pm

chemistry
calculate the Henry's law proportionality constant for N2? partial pressure at 1 atm=0.78 atm solubility at 1 atm= 5.3 x 10^-3 mol/L
Monday, August 25, 2014 at 8:16pm

chemistry
the vapor pressure of pure water at 60 c is 157 mmHg. what is the vapor pressure of this solution at the same temperature, in mm Hg?
Monday, August 25, 2014 at 8:05pm

chemistry
calculate the Henry's law proportionality constant for N2? partial pressure at 1 atm=0.78 atm solubility at 1 atm= 5.3 x 10^-3 mol/L
Monday, August 25, 2014 at 7:38pm

Nuhu Bamali Poly zaria Nig
Chemistry volumetric analysis. B is a solution of Na2CO3 containing 5g/dm3. A is a solution of oxalic acid of uknown concentration 25cm3 of 25.25,25.0 and 24.80 respectively (I) Calculate the average volume of acid used (II) The molar concentration of solution A (III) The ...
Monday, August 25, 2014 at 7:33pm

chemistry
Gallium Arsenide ---------------- The charge carrier density of GaAs at 31o C is 2.25x106 cm-3. What is the charge carrier density (in cm-3) at 175oC? (The bandgap of GaAs is 1.42 eV. )
Monday, August 25, 2014 at 7:32pm

chemistry
what is the solubility of N2 at a pressure of 10 atm? partial pressure at 1 atm=0.78 atm solubility at 1 atm= 5.3 x 10^-3 mol/L
Monday, August 25, 2014 at 7:26pm

chemistry help!
The Colorado River is diverted to flood fields. If the river is flowing at 17,600 ft3/s , how long will it take to flood a 5500 acre field to a depth of 2.00 meters? Note that 1 acre=43560ft2.
Monday, August 25, 2014 at 6:55pm

chemistry
The charge carrier density of GaAs at 31oC is 2.25x106 cm-3. What is the charge carrier density (in cm-3) at 175oC? The bandgap of GaAs is 1.42 eV.
Monday, August 25, 2014 at 3:17pm

Chemistry
At 1 atm, how much energy is required to heat 43.0 g of H2O(s) at –22.0 °C to H2O(g) at 169.0 °C?
Monday, August 25, 2014 at 10:37am

Chemistry
what is the symbol for gold
Monday, August 25, 2014 at 10:08am

AP Chemistry
4.50 grams of sodium phosphate is mixed with 3.75 grams of barium nitrate. How many grams of barium phosphate can be produced?
Monday, August 25, 2014 at 2:40am

chemistry
Propylene (or propene in proper IUPAC nomenclature), H2C=CH-CH3, can be reacted by addition polymerization to form polypropylene (PP). The process is initiated with the radical, I*. Choose the image above that properly indicated the location of the unpaired electron, *. What ...
Monday, August 25, 2014 at 1:36am

chemistry
Select the appropriate electron domain arrangement for ICl3 If you are using electron pairs in your structure, they can be noted with (ep). > I choose trigonal-bipyramidal What is the atomic geometry of this molecule? > I think this only wants the atoms without the lone ...
Sunday, August 24, 2014 at 10:47pm

chemistry
a)Rank the following 3 tetrachloride compounds in terms of increasing boiling point: carbon tetrachloride (CCl4), methane (CH4), dichloromethane (CH2Cl2) b) Which molecule ( KI or LiF ) has the higher boiling point? c)Select the single most important reason below to justify ...
Sunday, August 24, 2014 at 10:42pm

Chemistry
Jimmy is riding his bike at a speed of 5.5m/s. How long will it take him to go 2 miles? I tried using Dimensional Analysis, but how could you go from 5.5 miles a second to 2 miles?
Sunday, August 24, 2014 at 9:18pm

chemistry
In an effort to purify the output from a catalytic chemical reaction, C-Cl bonds are to be broken in a gaseous compound by means of LASER radiation. Determine the longest wavelength of radiation still capable of breaking the C-Cl bond. Express your answer in meters. [Given: ...
Sunday, August 24, 2014 at 8:11pm

chemistry
A 35.0g sample of ethylene glycol is dissolved in 500.0g of water. The vapor pressure of water at 32C is equal to 35.7mm Hg. What is the vapor pressure of the water-ethylene glycol solution at 32C?
Sunday, August 24, 2014 at 2:30pm

chemistry
The concentration of CO2 in an unopened soda can is 0.0506 m at 25 C. What is the partial pressure of CO2 gas in the can?
Sunday, August 24, 2014 at 2:24pm

chemistry
Determine the potential (V) by which a proton must be accelerated so as to assume a particle wavelength of 0.0293 nm. ---- This is what I did, dunno if right - wavelength in meters = 2.93*10^-11 m - used DeBroglie relation to find energy lambda = h / mv, v from kinetic energy...
Sunday, August 24, 2014 at 2:08pm

chemistry
The partial pressure of O2 in your lungs varies from 25 mm Hg to 40 mm Hg. What mass of O2 can dissolve in 1.0L OF water at 25.0oC when the O2 partial pressure is 40. mm Hg?
Sunday, August 24, 2014 at 1:59pm

chemistry
Calculate the wavelength (in m) of a photon capable of exciting an electron in Li2+ from the state n= 3 to the state n=5
Sunday, August 24, 2014 at 11:37am

chemistry
a) Calculate the number of moles of nitrogen dioxide, NO2, that could be prepared from 79.0 mol of nitrogen oxide and 82.0 mol of oxygen. 2NO(g)+O2(g)⟶ 2NO2(g) b) Identify the limiting reagent and the excess reagent in the reaction. What would happen to the potential ...
Sunday, August 24, 2014 at 10:20am

chemistry
explain how to prepare a 200cm,0.25 ofH2SO4
Sunday, August 24, 2014 at 8:26am

Chemistry
8-hydroxyquinoline (Q) can complex and precipitate many metals. A mixture of the aluminium and magnesium complexes weighed 1.0843g (MW=459.43; 312.61). When ignited, the mixture decomposed and left a residue of Al203 (MW 101.96) and MgO (MW 40.304) weighing 0.1344g. What is ...
Sunday, August 24, 2014 at 8:09am

Chemistry
If 175 grams of CsCl in 100 grams of water at a temperature of 100C will it be saturated or unsaturated?
Sunday, August 24, 2014 at 5:56am

chemistry
Which of following statements correctly describes energy levels? A. Electrons can never move to a higher or lower energy level. B.In it's outermost energy level, oxygen has 4 valence electrons. C. The second energy level holds a maximum of eight electrons. D. The greater ...
Saturday, August 23, 2014 at 9:36pm

chemistry
Which statement best describes the oxidation numbers of the atoms found in magnesium chloride? A. Magnesium has a 22 oxidation number and chlorine has 1+ oxidation number. B. Magnesium has 1+ oxidation number and chlorine has a 12 oxidation number. C. Magnesium has 22 ...
Saturday, August 23, 2014 at 8:36pm

chemistry
What is the proper name for MgSO4/H2O? A. Manganese sulfate hexahydrate B. Magnesium sulfite dihydrate C. Magnesium sulfite heptahydrate D. Magnesium sulfate heptahydrate
Saturday, August 23, 2014 at 8:10pm

chemistry
Which statement correctly describes an atom of the element helium? A. An atom of helium has its valence electrons in it's first energy level. B. An atom of helium most similarly behaves like an atom of hydrogen since it is in the same period. C. An atom of helium has a ...
Saturday, August 23, 2014 at 7:59pm

chemistry
When water decomposes into oxygen and hydrogen, the mass A. increases B. varies according the number of hydrogen and oxygen molecules that form. C. remains constant D. decreases
Saturday, August 23, 2014 at 7:49pm

Chemistry
The piperazine content of an impure commercial material can be determined by precipitating and weighing the diacetate: (C2H4)2N2H2 + 2 CH3COOH → (C2H4)2N2H2(CH3COOH)2 In one experiment, 0.3126 gram of the sample was dissolved in 25 mL of acetone, and 1 mL of acetic acid...
Saturday, August 23, 2014 at 1:54pm

chemistry
calculate the amount of water in grams that must be added to 5.00 grams of urea (NH2)2 CO in the preparation of a 16.2 percent by mass, and 26.2 grams of MgCl2 in the preparation of a 1.5 percent by mass solution.
Friday, August 22, 2014 at 5:39pm

AS Chemistry
which ions are present in a solution of ethanol in an excess of concentrated sulphuric acid? 1 CH3CH2O- 2 CH3CH2OH2 3 HSO4- Explain please! Thanks :)
Friday, August 22, 2014 at 10:36am

chemistry
Ions in aqueous solution that are surrounded by polar water molecules are said to be saturated. is it true or false?
Friday, August 22, 2014 at 10:06am

chemistry
hydrogen gas has a Henry's law constant of 1.07e-6 M/mm Hg at 25 Celsius when dissolving in water. if the total pressure of gas (H2 gas plus water vapor) over water is 1.0atm, what is the concentration of H2 in the water in grams per milliliter?
Friday, August 22, 2014 at 9:54am

Chemistry
Full question: An alcohol of molecular formula C4H10O2 contains two OH groups and has an unbranched carbon atom chain. On reaction with excess hot potassium permanganate this alcohol is converted into a compound of molecular C4H6O4 To which carbon atoms in the chain of the ...
Friday, August 22, 2014 at 5:11am

Chemistry
The most abundant noble gas in atmosphere among He, Kr, Ar, Xe?
Friday, August 22, 2014 at 2:16am

Chemistry
Why neon gas is used in botanical gardens and green houses? Why KrF6 doesn't exist? Why helium can diffuse through rubber,PVC and even glasses? Show two-center-two electron bonds and three-center-four electron bonds in B2H6?
Friday, August 22, 2014 at 2:12am

Chemistry
Attachment of [XeF]+ ions with [AsF6]- ions in their compound
Friday, August 22, 2014 at 2:06am

chemistry
A mixture of CO and CO2 having a volume of 20 ml is mixed with x ml of oxygen and electrically sparked. The volume after explosion is (16 + x)ml under the same conditions. What would be the residue volume if 30 ml of the original mixture is treated with aqueous NaOH? (a) 12 ml...
Thursday, August 21, 2014 at 5:26pm

chemistry
An aqueous solution is 40.0% by mass hydrochloric acid, HCl, and has a density of 1.20 g/mL. The molality of hydrochloric acid in the solution is m.
Thursday, August 21, 2014 at 4:52pm

chemistry
An aqueous solution of cobalt(II) nitrate has a concentration of 0.471 molal. The percent by mass of cobalt(II) nitrate in the solution is %.
Thursday, August 21, 2014 at 4:43pm

chemistry
How many grams of NiI2 are there in 263 grams of an aqueous solution that is 33.5 % by weight NiI2.
Thursday, August 21, 2014 at 4:33pm

Chemistry
1.50g of NaHCO3 is dissolved in 17.1g of water. Express the solubility of NaHCO3 in grams per 100g of solvent and calculate the % composition of NaHCO3 and water.
Thursday, August 21, 2014 at 4:31pm

chemistry
How many grams of NaOH are there in 187 grams of an aqueous solution that is 7.06 % by weight NaOH.
Thursday, August 21, 2014 at 4:22pm

chemistry
Hydrogen and chlorine react to yield hydrogen chloride: H2+ Cl2 ( 2HCl. How many grams of HCl are formed from reaction of 3.56 g of H2 with 8.94 g of Cl2? Which reactant is limiting?
Thursday, August 21, 2014 at 1:42pm

chemistry
sulphur+iron filings
Thursday, August 21, 2014 at 10:52am

chemistry
one of the following scientists never made any contribution to the development of periodic table? (a)j.jthompson (b)John Newlands (c) Luther Meyer ( d) mendeleev
Thursday, August 21, 2014 at 6:45am

Chemistry
To identify a diatomic gas (X2), a researcher carried out the following experiment: She weighed an empty 5.3-L bulb, then filled it with the gas at 1.30atm and 27.0 ∘C and weighed it again. The difference in mass was 7.9g . Identify the gas. Express your answer as a ...
Wednesday, August 20, 2014 at 8:16pm

Chemistry
Imagine that you have a 7.00L gas tank and a 3.50L gas tank. You need to fill one tank with oxygen and the other with acetylene to use in conjunction with your welding torch. If you fill the larger tank with oxygen to a pressure of 135atm , to what pressure should you fill the...
Wednesday, August 20, 2014 at 7:30pm

Chemistry
An ideal gas cannot be... A. condensed B. cooled C. heated D. compressed
Wednesday, August 20, 2014 at 7:59am

chemistry
A chemist needs 33.5 g of concentrated sulfuric acid for an experiment. The density of concentrated sulfuric acid is 1.84 g/mL. What volume of the acid is required? I know this is a conversion problem I'm just confused on where the numbers go.
Tuesday, August 19, 2014 at 11:03pm

Science
Justin wants to be the captain of an aircraft carrier when he gets out of school. Which subjects should Justin study to help him prepare for his career? A.biomedical science and meteorology B.oceanography and paleontology C.chemistry and biology D.physics and computer science ...
Tuesday, August 19, 2014 at 2:08pm

Science
Which branches of science do pharmacists need knowledge of to do their job properly? A.physics and chemistry B.biology and chemistry C.chemistry and geology D.physics and computer science Is the answer B?
Tuesday, August 19, 2014 at 1:59pm

chemistry calculations
At some temperature, the reaction PCl3(g)+Cl2(g)====PCl5(g) is at equilibrium when the concentration of PCl3, Cl2, and PCl5 are 10, 9.0, and 12 mol/L, respectively. Calculate the value of Kc for this reaction at that temperature.
Tuesday, August 19, 2014 at 8:11am

Chemistry
A 8.5 L sample is collected at 45 degrees C. What will the volume be if the temperature is raised to 70 degrees C.
Tuesday, August 19, 2014 at 8:04am

Chemistry
A student measures k for a certain blue due to be 19.4 m^-1 at 560 nm. What is the molarity of the dye in a solution with an absorbance of .118 at this wavelength ?
Tuesday, August 19, 2014 at 7:41am

CHEMISTRY
H2So4+S2=2S2+H2O
Tuesday, August 19, 2014 at 4:01am

physical science (chemistry)
calculate the number of atoms in 50 dm3 nitrogen gas
Monday, August 18, 2014 at 4:35pm

chemistry
what is the molar concentration of a solution containing 15,0 g of pottasium chloride in 1,30 dm3 of solution
Monday, August 18, 2014 at 12:49pm

chemistry
Equilibrium constant K for some reaction at temperature 300K was found to be 100 .Calculate equilibrium for same reaction at 400K if R= 8.23 change in enthalpy is 5000J
Monday, August 18, 2014 at 9:23am

chemistry
A student needs 1.00 mol of H2SO4 for an experiment. How many liters of 0.60 M H2SO4 does she need to obtain?
Monday, August 18, 2014 at 1:37am

chemistry
blance this equestion with partial balincing method:- Zn+HNo3(very dil)
Sunday, August 17, 2014 at 11:14pm

chemistry
Lovastatin is an anti-cholesterol drug that can be easily extracted from oyster mushrooms. A 291 mL lovastatin solution with a concentration of 0.001479 mol L-1 was extracted from 50 g of dried oyster mushrooms. Calculate the percentage of lovastatin in the mushrooms. ...
Sunday, August 17, 2014 at 9:00pm

Chemistry
How would I find the concentration of an unknown acid if I have a Ka value of 3.98x10^-5?
Sunday, August 17, 2014 at 3:46pm

chemistry
calculate the concentration of ammonium nitrate solution.
Sunday, August 17, 2014 at 8:43am

chemistry
if the wavelength of the first line in the balmer series in a hydrogen spectrum is 6863A .calculate the wavelength of the line in the lyman series in the same spectrum
Sunday, August 17, 2014 at 5:16am

chemistry
an endothermic reaction a to b has an activation energy of 15 kcal per mol and heat of reaction 5 kcal per mol the activation energy for the reaction b to a will be ?
Sunday, August 17, 2014 at 12:56am

chemistry
ferus amonium sulphate reaction with sulphuric acid
Saturday, August 16, 2014 at 4:07am

chemistry
ferusamoniumsulphate reaction with sulphuric acid
Saturday, August 16, 2014 at 3:54am

Chemistry
A cow weighing 1317 slug can yield10% steak. Steak may contain 5.8 % fat. How many milligrams of fat can you get from 0.548 slug of steak? (1 slug = 14.59 kg) Answer in units of mg I started the conversion by converting slugs to kg, but I didn't know what to do after that...
Saturday, August 16, 2014 at 12:44am

chemistry
How many moles of atoms are there in 32g of sulfur?
Friday, August 15, 2014 at 9:11pm

chemistry
1) 1.12 dm3 of a gas at STP is found to weigh 3.55g.Find molecular weight and vapour density of gas 2)5.6 dm3 of a gas at STP weighs 11g Find out its relative molecular mass & vapour density
Friday, August 15, 2014 at 10:19am

chemistry
a radioactive substance decays 10% in 5 days. The amount remains after 20 days?
Friday, August 15, 2014 at 9:22am

science (chemistry)
filter paper is a poor material on which to powder a solid before introducing it into a melting tube .explain why?
Thursday, August 14, 2014 at 6:35pm

chemistry
kc expression for aluminum+hydrochloric acid
Thursday, August 14, 2014 at 8:14am

physical chemistry
In an experiment, at a total pressure of 10atm and 400 degree celcius, the equilibrium mixture 2NH3=N2+3H2 the ammonia was found to have dissociated to the extent of 96%. Calculated Kp for the rxn. (reversible rxn).
Thursday, August 14, 2014 at 4:49am

Chemistry
I am given that volume of an unknown acid is 25 mL, volume of NaOH is 13 mL and concentration of NaOH is 1.0 M. I have a graph of a titration curve where the equivalence point is pH=9 (pH on y axis and volume of NaOH on x axis) How would i find the pKa value as well as the Ka ...
Wednesday, August 13, 2014 at 12:41pm

chemistry
9. The reaction of 50 mL of N2 gas with 150 mL H2 gas to form ammonia via the equation: N 2(g) + 3H2 (g) → 2NH3 (g) will produce a total of mL of ammonia if pressure and temperature are kept constant
Tuesday, August 12, 2014 at 5:46pm

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