Friday
August 28, 2015

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
How many grams of aspirin are present in 0.50 mole of aspirin?
Tuesday, March 17, 2015 by Anonymous

biology/ chemistry
how do electrolytes affect the formation of micelles?
Tuesday, March 17, 2015 by pan

chemistry
what is the iobic equation of zinc +iron(ll)sulphate solution
Tuesday, March 17, 2015 by demiz

Chemistry
Write equations for the separation of Fe2O3 from Bauxite ore, along with a short description of the process. I have no idea where to start for this question, any help would be appreciated!
Tuesday, March 17, 2015 by Anonymous

Chemistry
A certain reaction has an activation energy 52.93 kJ/mol. At what kelvin temperature will the reaction proceed 8.00 times faster than it did at 315K? Ea = 52.93 kJ/mol = 52930J R (gas constant) = 8.314 T1 = 315K k1 = rate constant at T1 T2 = ? k2 = rate constant at k2 = 8.00 ...
Tuesday, March 17, 2015 by Jessica

chemistry
Ammonia is often produced by reacting nitrogen gas with hydrogen gas. How many liters of ammonia gas can be formed from 12.9 L of hydrogen gas at 93.0°C and a pressure of 43.5 kPa? (Assume an excess amount of nitrogen gas.) I have absolutely no idea how to begin this.
Tuesday, March 17, 2015 by kendall

Chemistry
I just want to make sure that D is the correct answer. Each halogen is a diatomic element. However, under normal conditions chlorine is a gas, bromine is a liquid, and iodine is a solid. What is the best explanation for this difference? A. The strength of the covalent bond ...
Tuesday, March 17, 2015 by Cortney

chemistry
I believe the answer is c I just wanted to make sure. What can help overcome a positive enthalpy of solution and allow a solid solute to dissolve in water? A. A decrease in entropy B. A large amount of energy released C. An increase in entropy D. A large amount of energy absorbed
Tuesday, March 17, 2015 by Cortney

chemistry
A mixture of gases contains 0.235 mol CO2, 0.124 mol CO, and 0.326 mol O2. If the total pressure of the mixture is 4.62 atm, what is the partial pressure of each gas?
Tuesday, March 17, 2015 by James J

chemistry
C6H12O6(s) + 9 O2(g) --------- 6 CO2(g) + 6 H2O(g) What volume of oxygen gas measured at 27oC and 0.987 atm is needed to react with 8 g of C6H12O6? (C-12.01, H-1.008, O-16.00).
Tuesday, March 17, 2015 by James J

Chemistry
The starting material in this synthesis experiment Fe(NH4)2(SO4)2*6H2O. What is the ionic charge of the atom? Show your calculations
Tuesday, March 17, 2015 by Tyler

chemistry
2.241 g sample of nickel combines with oxygen to produce 2.852 g of metal oxide. Calculate the number of grams of xygen in the metal oxide.
Tuesday, March 17, 2015 by Julie

Chemistry
Enthalpy Change Given the following reactions: S(s) + O2(g) → SO2(g) ΔH = -297 kJ/mol SO2(g) + ½ O2(g) → SO3(g) ΔH = -141 kJ/mol Calculate the ΔH for the reaction: S(s) + 3/2O2(g) → SO3(g)
Tuesday, March 17, 2015 by chem_01

chemistry
When a mixture of two black powders is heated, it gave off a gas which turned lime water milky Give a chemical equation to show the reaction between gas and lime water Red scales residue can be seen on the black residue. Name the red scales The red scale residue partly ...
Tuesday, March 17, 2015 by saurav

Chemistry
how many grams of potassium hydroxide would need to be added to 400 mL of 0.150M HNO3 to raise its pH to 2.5
Tuesday, March 17, 2015 by Ruth

Chemistry
an unknown salt is either NaCN,NaC2H3O2, NaF, NaCl, or NaOCl. when 0.100 molar of the salt is dissolved in 1.00 L of solution, the ph of the solution is 8.07. what is the identity of the salt? where do I start? How do I solve it, cuz im not gettign right answer.
Tuesday, March 17, 2015 by DF

Chemistry
Container A contains argon gas at 0C and pressure 380mmHg. Container B of volume 700 ml contains neon gas at 25C and pressure of 3atm. Both of these gases are placed in a 2L vessel at 273K and the total pressure is 1.46atm. What is the volume of container A?
Monday, March 16, 2015 by Karrie

Chemistry
HCI is a strong acid. What is the ion concentration, (H+), of a 0.0015M solution of HCI? What is the pH of a 0.0015M solution of HCI? I have looked in my book but it not making sense. I am not sure where to even start the problem. A little guidance please
Monday, March 16, 2015 by Yvonne

chemistry
If a solution of lead iodide has [I-] = 1.1x10-4 M, what is the lead(II)ion concentration at equilibrium?
Monday, March 16, 2015 by paula

chemistry
The enthalpy of formation of MX is ΔHf° = –493 kJ/mol. The enthalpy of sublimation of M is ΔHsub = 143 kJ/mol. The ionization energy of M is IE = 437 kJ/mol. The electron affinity of X is ΔHEA = –317 kJ/mol. (Refer to the hint). The bond energy of ...
Monday, March 16, 2015 by megan

Physical Chemistry
If a 30g piece of ice at -5C is immersed in 125mL of water at 25C in an insulated container... A. Determine the final temperature and final composition of the system B. Determine the entropy changes of the ice and the water and the overall entropy change of this process.
Monday, March 16, 2015 by Jo

Chemistry
How much heat is required to convert 6.78g of ice at − 14.0∘C to water at 24.0∘C ?
Monday, March 16, 2015 by Kirsten

Chemistry
1. Imagine you have a saturated solution of Ca(OH)2, at equilibrium, that has some undissolved Ca(OH)2 precipitated on the bottom of the test tube. If you add an additional scoop of Ca(OH)2 to the solution will concentration of [OH-] in the solution (increase, decrease, or be ...
Monday, March 16, 2015 by Caroline

chemistry
The number of moles of solute in a bottle containing 300 mL of 0.178 mol/L sodium sulfite solution is
Monday, March 16, 2015 by ronnie

chemistry
The concentration of a solution made by diluting 10.0 mL of 0.685 mol/L NaBr to 300 mL is
Monday, March 16, 2015 by ronnie

chemistry
I need an example of an elementary reaction to go with the definition An elementary reaction is a reaction in which reactants are converted to products in a single step.
Monday, March 16, 2015 by alyssa

AP Chemistry
To have a buffer with a pH of 2.50, what volume of 0.510 M NaOH must be added to 100. mL of 0.230M H3PO4?
Monday, March 16, 2015 by Shannon

chemistry
A restaurant serves tea in aluminum mugs. The aluminum mug has a mass of 125 g, initially at 24.0 oC with 341 mL tea at 80.0oC. What is the final temperature of the tea after the tea and mug attain equilibrium. Assume the tea has the same specific heat capacity and density as ...
Monday, March 16, 2015 by treasa

Chemistry
How many oxygen atoms are in 6Al (SO4)3
Monday, March 16, 2015 by science wiz

chemistry
How to prepare 14M Sulfuric acid
Monday, March 16, 2015 by Vitthalsing Rajput

CHEMISTRY
How many moles of methane gas, CH 4 , are in a 1.00×103L storage tank at STP?
Monday, March 16, 2015 by dakota

Chemistry
for a project i had to make cards with words and then an example of those words, and i've done almost all of them, but I have a few words I need examples for activation energy activation energy activated complex elementary reaction
Monday, March 16, 2015 by Alyssa

chemistry
In a coffee cup calorimeter, 50 mL of 0.1 M HCl and 50 mL of 0.1 M NaOH are mixed to yield the following reaction: HCl + NaOH  NaCl + H2O. The two solutions were initially at 22.1 oC and the final temperature is 24.2 oC. Calculate the heat that accompanies this ...
Monday, March 16, 2015 by Diana

chemistry
An aqueous solution contains 0.445 M ethylamine (C2H5NH2). How many mL of 0.226 M hydrochloric acid would have to be added to 150 mL of this solution in order to prepare a buffer with a pH of 10.200
Monday, March 16, 2015 by chem

chemistry
N2 + 3H2 = 2NH3. What is the DeltaGo of the following reaction? 33.5 kJ/mol 34.5 kJ/mol 35.5 kJ/mol 36.5 kJ/mol
Monday, March 16, 2015 by khursida

Chemistry
I need definitions for chemistry and I can't come up with any heterogeneous reaction homogeneous reaction activation energy activation energy activated complex elementary reaction
Monday, March 16, 2015 by Al

Chemistry
  show that the time dependent expectation value for the position x and momentum p match the solution of newton classical equation for HO drive the amplitude of vibration?
Monday, March 16, 2015 by lolo

Chemistry - Solubility
Calculate the solubility of copper(II) sulfide in a solution that is 0.150 mol L^-1 in NaCN. I am very confused on what to do. Since there are no common ions, I know that this is not the common ion effect. Also I do not believe this is a pH effect question. Is this a complex-...
Monday, March 16, 2015 by Karla

chemistry
Calculate how many grams of O2(g) can be produced from heating 31.8 grams of KClO3(s).
Sunday, March 15, 2015 by 7

chemistry
The power of the equation ΔG° = –RT ln(K) is that K can be determined from tabulated values of ΔG°f. Use the tabulated values of the Gibb's energy to determine K for the reaction, 2AB(l) ↔ 2A(g) + B2(g), at 298K. (R=8.314 J/K mol or R=0.008314 ...
Sunday, March 15, 2015 by Carl

Chemistry
Calculate the pH during the titration of 10.00 mL of 0.400 M hypochlorous acid with 0.500 M NaOH. The Ka for HOCl is 3.0 x 10-8 M. What is the pH at the equivalence point? I used the HH formula and got pH=7.52+log(.222)=6.87, but its not right.
Sunday, March 15, 2015 by JUNDY

Chemistry
Calculate the pH during the titration of 10.00 mL of 0.400 M hypochlorous acid with 0.500 M NaOH. The Ka for HOCl is 3.0 x 10-8 M. What is the pH when half the acid has been neutralized? 'I got 7.82 by using the HH formula but its wrong, help.
Sunday, March 15, 2015 by JUNDY

Chemistry
Concentrated hydrochloric acid is 38% HCl by weight and has a density of 1.19 g/mL. A solution is prepared by measuring 70 mL of the concentrated HCl, adding it to water, and diluting to 0.500 L. Calculate the approximate molarity of this solution from the volume, percent ...
Sunday, March 15, 2015 by JUNDY

chemistry
hi I have a hard time understanding the following question: The
Sunday, March 15, 2015 by juju

physics/chemistry
Okay so I want to solve for refractive index. I'm given the dielectric constant and the permeability M. From what I understand the refractive index is frequency dependent. I'm just unsure what equation to use. n=(Er)^1/2 does not work because the dielectric constant ...
Sunday, March 15, 2015 by Zed

chemistry
a) calculate the concentration of your unknown (Gatorade) using correct units Note if you did not run the Gatorade use absorbance =0.205 abs units in order to calculate the concentration of the dye in the Gatorade b) calculate of % T for an absorbance of 1.5 using the result. ...
Sunday, March 15, 2015 by mathew

chemistry
Suppose a reaction has the equilibrium constant K = 2.3 10-7 at a particular temperature. Will there be a large or small amount of unreacted starting material present when this reaction reaches equilibrium? a)There will be a small amount of unreacted starting material present ...
Sunday, March 15, 2015 by andy

chemistry
H2(g)+ o2(g)-> H20(l) (delta)Hf(h20(l)=-286 kj/mol the total volume of hydrogen needed fill the hindenberg was 2.3 x 15^5 m^3. what is the theoretical yield of heat (that which could have been evolved) when the hindenberg exploded, assuming all the hydrogen reacted?
Sunday, March 15, 2015 by Jack

Chemistry
Calculate the pH during the titration of 10.00 mL of 0.400 M hypochlorous acid with 0.500 M NaOH. The Ka for HOCl is 3.0 x 10-8 M. What is the pH when half the acid has been neutralized? 'I got 7.82 by using the HH formula but its wrong, help.
Sunday, March 15, 2015 by JUNDY

chemistry
An aqueous solution contains 64g of ethanol( C2H5OH) in 122 grams of solution. The mole fraction of ethanol is:
Sunday, March 15, 2015 by anon

Chemistry
Calculate the pH during the titration of 10.00 mL of 0.400 M hypochlorous acid with 0.500 M NaOH. The Ka for HOCl is 3.0 x 10-8 M. What is the pH at the equivalence point? I used the HH formula and got pH=7.52+log(.222)=6.87, but its not right.
Sunday, March 15, 2015 by JUNDY

Chemistry
What will happen to the number of moles of SO3 in equilibrium with SO2 and O2 in the following reaction in each of the following cases? 2 SO3(g) equilibrium reaction arrow 2 SO2(g) + O2(g) ΔH° = 197 kJ (a) Oxygen gas is removed. increase decrease stay the same (b) The...
Sunday, March 15, 2015 by Sally

chemistry
CaSiO3(s) +6 HF (g)-> CaF2(aq) + SiF4 (g) + 3 H2O(l) If a 65.6 g sample of CaSiO3 is reacted in an inert 83 L container at 25.5°C with HF at 1.00 atm pressure find the following. a. the mass of water, and CaF2 produced in the reaction and the mass of HF that remains. b...
Sunday, March 15, 2015 by joe

chemistry
CaSiO3(s) +6 HF (g)-> CaF2(aq) + SiF4 (g) + 3 H2O(l) If a 65.6 g sample of CaSiO3 is reacted in an inert 83 L container at 25.5°C with HF at 1.00 atm pressure find the following. a. the mass of water, and CaF2 produced in the reaction and the mass of HF that remains. b...
Sunday, March 15, 2015 by Val22

Chemistry
Ammonium nitrate (NH4NO3) is an important agricultural industrial chemical as it provides readily available nitrogen for plant growth, and one can buy 50. pounds of ammonium nitrate for $38. Urea (CO(NH2)2) is an attractive alternative, and, not being a pre-cursor to an ...
Sunday, March 15, 2015 by Val22

Chemistry
Oil and water don't mix. We say that oil is
Saturday, March 14, 2015 by Kris

H Chemistry
if 1.01x103 ml of h2o gas at stp is compressed into o.345ml container what would the new pressuer be
Saturday, March 14, 2015 by angie

Chemistry
How many millilitres of a 0.1 M solution of NaF and of 0.1 M solution of HF must be mixed to obtain 1L of buffer at pH = 4? Ka = 6.7 × 10-4 Currently I am quite confident with using the henderson and Hasselbalch equation but this question has left me stumped... Any help ...
Saturday, March 14, 2015 by James Wilson

Chemistry
What is the cause of hexagonal structure ?
Saturday, March 14, 2015 by Ciaria

Chemistry
Given that 12.25 g of aluminum sulfide is reacted with excess water. How many grams of aluminum hydroxide can be obtained? The molar mass of aluminum sulfide is 150.0 g and the molar mass of aluminum hydroxide is 78.0 g.
Saturday, March 14, 2015 by Catherine

Chemistry
Describe the procedure to prepare this solution: 100 mL of a solution 0.1 M of KMnO4 Help? I don't understand what this implies.
Saturday, March 14, 2015 by Amy

Chemistry
Suppose 0.500 g of sulfur combines with 1.00 g of copper. What is the empirical formula of the compound? The atomic mass of sulfur is 32.065 g and the atomic mass of copper is 63.546 g.
Saturday, March 14, 2015 by Catherine

chemistry
what are the islamic values in the experiment composition of potassium chlorate?I have to do lab report about the topic and the due date is around the corner.please help me..
Saturday, March 14, 2015 by student

Chemistry help
Write two molecular formulas that reduce to each to each of the given empirical formulas. Do not include the given empirical formulas. 1. Al2(SO4)3 . Cr(CN)3
Saturday, March 14, 2015 by Anonymous

Chemistry help
washing soda is a hydrate of sodium carbonate. a 2.714 g sample of washing soda is heated until a constant mass of 1.006 of na2co3 is reached. what is the mass of the water evaporated? what is the percent water in the compound?
Saturday, March 14, 2015 by Anonymous

chemistry
the wave length of the first line of the Lyman series of hydrogen is identical to the second line of the Balmer series for some hydrogen like ion 'X'.Identify the ion.
Saturday, March 14, 2015 by babai

SCIENCE(CHEMISTRY)
calculate the mass of silver deposited when a current of 2.6a is passed through a solution of a silver salt for 70mins ag=108,1 faraday 96500
Saturday, March 14, 2015 by MIRACLE IWUNZE

chemistry
Hey DrBoB222 I was wondering if you could help me with that problem just a little bit ago again?
Saturday, March 14, 2015 by jack

chemistry
I would love help on trying to start this problem?
Friday, March 13, 2015 by jack

chemistry
Several reactions are carried out using AgBr, a cream-colored silver salt for which the value of the solubility product constant, Ksp, is 5.0 x 10-13 at 298 K. a) Calculate the value of [Ag+] in 50.0 mL of a saturated solution of AgBr at 298 K. b) A 50.0 mL sample of distilled...
Friday, March 13, 2015 by jack

chemistry
What is the strongest intermolecular force that occurs between carbon dioxide molecules? A. London dispersion forces B. Hydrogen bond C. Covalent bond D. Dipole-induced dipole attractions I think the answer is D but I am not sure
Friday, March 13, 2015 by Morgan

chemistry
What volume of 0.050 M AgNO3, silver nitrate solution is required to reat completely with 60.0 mL of 0.025 M K2S, potassium sulfide?
Friday, March 13, 2015 by AJ

Chemistry
Rolaids is an over the counter remedy for upset stomachs that functions by reacting with stomach acid. The active ingredients are calcium carbonate (550 mg) and magnesium hydroxide (110 mg). The inactive ingredients are dextrose, flavoring, magnesium stearate, polyethylene ...
Friday, March 13, 2015 by Jen24

chemistry
If you dissolve 220.3 Pounds of ammonium nitrate in water to obtain a final solution volume of 500. gallons what is the [NH4+] (of course in mol/L)?
Friday, March 13, 2015 by Jaxx

Chemistry ( HELP PLEASE!!! )
Consider the reaction H3PO4+ 3NaOH→Na3PO4+ 3H2O. How much Na3PO4 can be prepared by the reaction of 3.43 of H3PO4 with an excess of NaOH?
Friday, March 13, 2015 by Farrell

chemistry
A solution of fructose, C6H12O6, a sugar found in many fruits, is made by dissolving 22.0 g of fructose in 1.00 kg of water. What is the molal concentration of fructose the solution? What is the mole fraction of fructose in the solution? What is the mass percent of fructose in...
Friday, March 13, 2015 by Anonymous

Chemistry
Assuming that the lab procedure was conducted in an identical manner in all other respects, if a large quantity of vinegar had been taken initially for analysis, for example, a 50.0 ml instead of 25.0mL discuss briefly how each of the following would change. A. the moles of ...
Friday, March 13, 2015 by Liz

Chemistry
I did a lab on vinegar and titration. The question asks.. In the titration of acetic acid and NaOH the use of the color indicator mandates that excess base be present to detect the reading endpoint. Will this cause the calculated and reported mass percent of acetic acid in ...
Friday, March 13, 2015 by Liz

chemistry
describe how you can prepare 500cm of0.1m of standard hydrochloric acid from commercial concentrated HCL of density 1.18g/cm and percentage by 37%
Friday, March 13, 2015 by Anonymous

Chemistry
The reason that nonpolar oil will not dissolve in polar water is that the attractive forces between: A. the oil molecules are ionic and the attractive forces between the water molecules are covalent. B. the water molecules are weaker than the attractive forces between the ...
Friday, March 13, 2015 by Morgan

chemistry
if .5 g of a KHP containing unknown mixture requires 7 mL of NaOH to reach the endpoint of titration, what mass of the unknown should be weighed out to consume 20 mL of the NaOH. If anyone could help me start this that would be appreciated. Thanks!
Friday, March 13, 2015 by lawerence

chemistry
600 gallons of 15 M nitric acid were added to a lake. The initial pH of the lake was 5.90 and the final pH was 3.70. What is the volume of the lake?
Friday, March 13, 2015 by mar

Chemistry
An electron has an uncertainty in its position of 507pm. What is the uncertainty in its velocity?
Friday, March 13, 2015 by J

chemistry
Stainless steel is an alloy of iron containing 5 percent nickel and 0. 175 percent chromium. How much chromium is present in a 72.2 g sample of this alloy? Answer in units of mol.
Friday, March 13, 2015 by DJ

chemistry
What is the % carbon by weight in 1.7 grams of potassium carbonate (K2CO3)? Answer in units of %.
Friday, March 13, 2015 by DJ

CHEMISTRY
How many atoms of carbon are present in 12.9 g of a compound that is 36 .7% carbon, by weight? Answer in units of atoms.
Friday, March 13, 2015 by DJ

chemistry
describe how you can prepare 500cm of 0.1 of hydrochloric acid from commercial Hcl of density 1-18g/cm and the percentage by mass 37%
Friday, March 13, 2015 by kennedy

chemistry
The Kw of water varies with temperature. Calculate the pH of water at 46⁰C with a Kw = 1.219 x 10-14. Show all calculations leading to an answer.
Friday, March 13, 2015 by Ciaria

Chemistry
If 5.40 kcal of heat is added to 1.00 kg of ice at 0⁰C, how much liquid water at 0⁰C is produced? Show all calculations leading to an answer.
Friday, March 13, 2015 by Ciaria

chemistry
what's the lewis dot diagram for methanol?
Friday, March 13, 2015 by Laura

Chemistry
The density of air is about 1.29g/l at standard temp and pressure . Would carbon dioxide rise up or sink in the atmosphere ? Thanks:)
Friday, March 13, 2015 by Maya

chemistry
Show the calculation of (1) the expected grams of urea (CH4N2O) formed in the reaction of 6.5 grams of lead cyanate (Pb(CNO)2) with excess ammonium hydroxide and then show the calculation of (2) the % yield if the actual yield of urea is 1.89 grams. Reaction is shown below: Pb...
Thursday, March 12, 2015 by emily

chemistry
Show the calculation of (1) the expected grams of aspirin (C9H8O4) formed in the reaction of 2.7 grams of salicylic acid (C7H6O3) with excess acetic anhydride and then show the calculation of (2) the % yield if the actual yield of aspirin is 1.44 grams. Reaction is shown below:
Thursday, March 12, 2015 by emily

chemistry
What salt results from the neutralization of acetic acid with potassium hydroxide?
Thursday, March 12, 2015 by Ciaria

chemistry
A student collected the following data for a fixed volume of gas: Temperature (C) Pressure (mm of hg) 10 726 20 750 40 800 70 880 100 960 150 ??? Fill in the missing data point. Show all calculations leading to an answer. is the answer 1025 ?
Thursday, March 12, 2015 by Ciaria

CHEMISTRY PLEASE!!! ( I NEED HELP ASAP)
Consider the reaction H3PO4 + 3NaOH → Na3PO4 + 3H2O. How much Na3PO4 can be prepared by the reaction of 3.43 g of H3PO4 with an excess of NaOH? For the reaction ?Fe+?H2O → ?Fe3O4 +?H2, what is the maximum amount of Fe3O4(231.533 g/mol) which could be formed from 12...
Thursday, March 12, 2015 by Farrell

chemistry
Calculate the volume 2.3g of oxygen gas at 28 degrees celcius and 2.321 atm
Thursday, March 12, 2015 by Dean

chemistry
a) Describe how to determine if a reaction will be thermodynamically favorable. b) Describe what happens to the Gibbs Free Energy term when a chemical reaction is reversed. c) Describe how coupling reactions are used to drive an unfavorable chemical reaction.
Thursday, March 12, 2015 by Morgan

chemistry
At a certain temperature, the equilibrium constant, K, for this reaction is 53.3. H2(g)+I2(g)->2HI(g) At this temperature, the reactants were placed in a container to react. If the partial pressures of H2 and I2 were each 0.300 bar initially, what is the partial pressure of...
Thursday, March 12, 2015 by kelsey

chemistry
Explain how the geometry affects the ability of the molecules to experience a dipole affect. One molecule is a trigonal pyramidal while the other is a tetrahedral.
Thursday, March 12, 2015 by Morgan

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