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April 19, 2015

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

Chemistry
# of moles of oxygen in 2 L @ 24 deg C & 750 torr?
Monday, January 28, 2013 at 5:10pm

College Chemistry
How many moles of aluminum do 2.66×10^24 aluminum atoms constitute?
Monday, January 28, 2013 at 4:06pm

Chemistry
Determine the normality of 91.2 g of HCl in 4.3 L of solution. (Round to the nearest hundredth.)
Monday, January 28, 2013 at 3:56pm

College Chemistry
Upon decomposition, one sample of magnesium fluoride produced 1.66kg of magnesium and 2.56kg of fluorine. A second sample produced 1.25kg of magnesium.How much fluorine (in grams) did the second sample produce?
Monday, January 28, 2013 at 3:34pm

Chemistry
From the jewelry descriptions given, select the homogeneous mixture or solution. Answer?? 10 carat (K) electroplated gold jewelry 24 carat (K) gold jewelry (i know this is pure gold) 18 carat (K) gold jewelry Are these right? CaCl2>>calcium chloride NaF>>>sodium...
Monday, January 28, 2013 at 3:34pm

CHEMISTRY
write the balanced ionic equation of K2CO3+HCl
Monday, January 28, 2013 at 12:41pm

Chemistry
a sample of silver chromate has a mass of 78.6 grams?
Monday, January 28, 2013 at 12:07pm

Chemistry
​What is the point called on a graph of pH vs log {[A-]/[HA]} when [A-] = [HA]?   Graphs are listed as “y vs. x”.
Monday, January 28, 2013 at 11:56am

chemistry urgent urgent
... the hiv virus that causes aids destroys the immune system in the body. classify the hiv virus and explain the statement.
Monday, January 28, 2013 at 10:51am

Chemistry
how many half lives have passed if only 0.625g remain of the original 40g?
Monday, January 28, 2013 at 10:26am

college chemistry
calculate the specific heat for 18.5-g sample of tin that absorbs 183 J when its temp increases from 35.0 degrees celcius to 78.6 degress celcius. I don't know where to even start, help?
Monday, January 28, 2013 at 9:38am

Chemistry
The term mole is used in chemistry to define an amount of a substance. For example, a mole of glucose, blood sugar, weighs 180.16 grams. A common concentration unit for solutions is moles of substance per liter of solution. We abbreviate this with the symbol M. For example, 0....
Monday, January 28, 2013 at 9:11am

Chemistry
In the chlor-alkali process, the mass of NaCl(s) required to produce 0.793 kg of chlorine gas is _____ kg.
Monday, January 28, 2013 at 2:01am

chemistry
From the jewelry descriptions given, select the homogeneous mixture or solution. Answer?? 10 carat (K) electroplated gold jewelry 24 carat (K) gold jewelry (i know this is pure gold) 18 carat (K) gold jewelry Are these right? CaCl2>>calcium chloride NaF>>>sodium...
Monday, January 28, 2013 at 1:20am

chemistry
How many orbitals are contained in the n=2 level? Give the l and ml values of each of them.
Monday, January 28, 2013 at 12:52am

Chemistry
1.What is the pH of a solution containing 0.042 M NaH2PO4 and 0.058 M Na2HPO4 ? The pKa of sodium phosphate is 6.86. pH = 6.86 + log [0.058] / [0.042]; pH = 6.86 + 0.14; pH = 7.00 That is my answer to the above question. The following question is what I am having trouble with...
Sunday, January 27, 2013 at 11:00pm

Chemistry
Let say Pb(NO3)2 combine with FeCl3, would this yield PbCl + Fe(NO2)3? Thanks
Sunday, January 27, 2013 at 9:56pm

chemistry
What is the heat of combustion of ethane, C2H6, in kilojoules per mole of ethane?
Sunday, January 27, 2013 at 9:14pm

Chemistry
I'm asked to tell which of the following peptide segments is most likely to be part of a stable Alpha Helix at physiological pH? Only 1 can be chosen 1. gly-gly-gly-ala-gly 2. gly-arg-lys-his-gly 3. pro-leu-thr-pro-trp 4. lys-lys-ala-arg-ser 5. glu-leu-ala-lys-phe 6. glu-...
Sunday, January 27, 2013 at 8:58pm

chemistry
Assume you used 0.200g of salicylic acid and 0.480mL of acetic anhydride, and you obtain 0.152g of pure, recrystallized, dry aspirin. Calculate the percent yield.
Sunday, January 27, 2013 at 8:14pm

chemistry
Assuming equal concentration rank these by freezing points, Na3PO4, Li2Co3,NH4Cl, and Sn(NO3)4
Sunday, January 27, 2013 at 7:50pm

Chemistry
The specific heat capacity of butanone is 1.69J/grams Celsius and it's boiling point is 79 Celsius. If 1.250g of butanone at 15 Celsius is heated by adding 100J of energy, will it boil
Sunday, January 27, 2013 at 7:47pm

Chemistry (Biochem)
I'm given two pictures looking down the alpha helices of a coiled coil dimer of alpha-keratin. I'm asked to identify three statements out of the following that are true. My guesses are 2, 3, and 6. 1. Leu-Glu-His-Val-Cys-Lys-Ser is a likely repeat in the α helix ...
Sunday, January 27, 2013 at 6:01pm

Chemistry
How many grams of sucrose are needed to make 875 mL of a 39.0% (w/v) sucrose solution?
Sunday, January 27, 2013 at 4:22pm

chemistry
How many ml of 0.05M kmn04 acidic are diluted to oxidize 2gm of fes04 is diluted solution The answer 52.63 ml I want you step by step clearly explain Thank you for Bob
Sunday, January 27, 2013 at 3:23pm

Chemistry
In a mountainous location, the boiling point of pure water is found to be 95°C. How many grams of sodium chloride must be added to 9 kg of water to bring the boiling point back to 101°C? Assume that i = 2.
Sunday, January 27, 2013 at 2:59pm

chemistry
What weight of na2co3 of 95% purity would be required to neutralize 45.6ml of 0.235n acid? I want you step by step clearly explain answer 0.5978gm
Sunday, January 27, 2013 at 2:39pm

Chemistry
The specific heat of solid silver is 0.237 J/g degrees celsius and the heat of fusion of silver at its melting point of 961 degrees celsius is 11 J/g. Find the final temperature is 1490 J is used to heat 40 g of silver initially at 20 degrees celsius. Answer in units of ...
Sunday, January 27, 2013 at 2:35pm

chemistry
5ml of 8N Hn03, 4.8ml of 5N hcl and a certain volume of 17M h2s04 are mixed together and made up to 2 liter. 30ml of this acid mixture exactly neutralizes 42.9ml of na2c03, 10 h20 in 100ml of water .Calculate the amount of sulphate ion in gm present in solution Who help step ...
Sunday, January 27, 2013 at 2:32pm

chemistry
5ml of 8N HN03, 4.8ml of 5N HCL and a certain volume of 17M H2s04 are mixed together and made up to 2 liter 30ml of this acid mixture exactly neutralize 42.9ml of na2c03, 10 H2O in 100ml of water. Calculate the amount of sulphate 10m in gm present in solution The 6.5gm who help
Sunday, January 27, 2013 at 2:19pm

Chemistry
11.4mL of 0.7 M NaOH was used to titrate 5.0mL hydrochloric acid. What is the molarity of the acid? a) 0.3 b) 1.6 c) 3.9 d) 5.0 e) 8.1 Can someone answer this question and explain how to get the answer?
Sunday, January 27, 2013 at 2:15pm

chemistry
what weight of na2c03 of 95% purity would be required to neutralize 45.6ml of 0.235N acid? Who Helps
Sunday, January 27, 2013 at 2:14pm

Chemistry
Write the equation for the reaction associated with the Ka2 of sulfuric acid, H2SO4. Write the equation for the reaction associated with the Kb2 of carbonate, CO32–.
Sunday, January 27, 2013 at 1:52pm

Chemistry
For the oxidation of glucose ( C6H12O6 + 2O2---6H2O +6CO2), how many moles of O2 will it take to consume 6 moles of glucose. Can someone explain it?
Sunday, January 27, 2013 at 11:26am

chemistry
I need help on a balance ionic equation in chemistry Ca(NO3)2 + NaOH
Sunday, January 27, 2013 at 10:39am

Chemistry
what are the products when water,ferric chloride and ammonium thiocyanate are combined?
Sunday, January 27, 2013 at 8:53am

chemistry
how would you prepare a 550ml of 0.350 normal calcium chloride solution
Sunday, January 27, 2013 at 4:28am

Chemistry
Using chemical equations, show how the triprotic acid H3PO4 ionizes in water. Phases, such as (l) or (aq), are optional.
Sunday, January 27, 2013 at 1:41am

Chemistry
Write the equation for the reaction associated with the Ka2 of sulfuric acid, H2SO4. Write the equation for the reaction associated with the Kb2 of carbonate, CO32–.
Sunday, January 27, 2013 at 1:40am

Chemistry
The rate of a first-order reaction is followed by spectroscopy, monitoring the absorption of a colored reactant at 520 nm . The reaction occurs in a 1.29-cm sample cell, and the only colored species in the reaction has an extinction coefficient of 5700 cm-1M-1 at 520 nm . a) ...
Saturday, January 26, 2013 at 9:21pm

Chemistry
The rate of a first-order reaction is followed by spectroscopy, monitoring the absorption of a colored reactant at 520 nm . The reaction occurs in a 1.29-cm sample cell, and the only colored species in the reaction has an extinction coefficient of 5700 cm-1M-1 at 520 nm . a) ...
Saturday, January 26, 2013 at 9:21pm

chemistry
Assignment 1 Question Consider a monohydrogen phosphate ( HPO42-) and dihydrogen phosphate (H2PO4-) buffer solution. [HPO42-] = 0.063M [H2PO4-] = 0.10M What happens when you add 1.0 ml of 0.10 M HCl to the a 99ml solution? What would the pH of the solution be without the ...
Saturday, January 26, 2013 at 8:44pm

Biochemistry, Biology, Chemistry
An enzyme works on two substrates, S1 and S2. Its Km for S1 is 100mM and its Km for S2 is 10mM. Based on this information, answer the following questions: 1. For a given [E] will it have a higher Vmax for S1 or S2? Explain your answer 2. Is S1 or S2 a better substrate for the ...
Saturday, January 26, 2013 at 6:53pm

Chemistry
Using chemical equations, show how the triprotic acid H3PO4 ionizes in water. Phases, such as (l) or (aq), are optional.
Saturday, January 26, 2013 at 6:26pm

Chemistry
Air in the vicinity of a local power station contains 8.8x10^-4 gm^-3 SO2. What volume of 0.001moldm^-3 Iodine solution would be required to react with a solution obtained from 200dm^3 of contaminated air? The equation given is SO2 + I2 + 2H2O ==> H2SO4 + 2HI Thanks! :)
Saturday, January 26, 2013 at 6:04pm

Chemistry
Using oxidation numbers, explain why this reaction is not a redox reaction? CaCo3 --------> CaO + Co2 Please help.
Saturday, January 26, 2013 at 5:23pm

Chemistry
My Chem professor is out for the weekend and I'm confused about what the question is asking or the equations needed... A 10.0-g block of pure nickel (Cp = 0.445 J/g-°C) is brought to each of the temperatures below. A sealed beaker containing 15.0 g water at the ...
Saturday, January 26, 2013 at 3:27pm

AP Chemistry
Water is being electrolysed in the presence of a non-reactive electrolyte under standard conditions. If 2.5 amperes of current flows through the circuit for 13.6 minutes at 25 degrees celsius and 1 atmosphere, what volume of hydrogen gas is produced? Please, I need help with ...
Saturday, January 26, 2013 at 2:58pm

chemistry
Why does the compressed gas leaving the propane tank cause the temperature to drop around the valve?
Saturday, January 26, 2013 at 2:39pm

chemistry
a sample of sulphuric acid is 95.7% by mass and has a density of 1.84g/cubic cm.calculate the mass of pure H2SO4 in a 2.00L bottle and volume of acid that contain 200g of pure H2SO4.
Saturday, January 26, 2013 at 1:32pm

chemistry
What volume of 9.0Molarity of H2SO4 is required to react with 20.0g of NaOH?
Saturday, January 26, 2013 at 11:30am

chemistry
What volume of 0.010M silver nitrate will exactly react with 20ml of 0.0080M socium chloride solution?
Saturday, January 26, 2013 at 10:46am

Chemistry help
Write a descriptive text and a word equation on how silicon is extracted from earth's crust' .
Saturday, January 26, 2013 at 10:44am

chemistry
suppose u r given a conc soln of hcl which is known to be 37% hcl & has a soln density of 1.19g/ml. What is the molarity and molality of hcl in this soln
Saturday, January 26, 2013 at 9:21am

chemistry
what is the molarity of Cl in a 100ml solution containing 20g NaCl, 10g CaCl2, and 15g KCl
Saturday, January 26, 2013 at 8:21am

science,chemistry
constract the neutralisation rxn of calos antacid and stomach acid,and balance it?
Saturday, January 26, 2013 at 7:03am

chemistry
what is the equillibrium constant of each of the substance in the equillibrium when concentration of ICl was 0.75M 2ICl(g)=I2+Cl2 kc=o.12
Saturday, January 26, 2013 at 1:00am

chemistry
balance net Ionic solution AgNo3 + NaOH
Friday, January 25, 2013 at 10:15pm

chemistry
Write a balanced chemical equation for the reaction that occurs when dimethylether, , is combusted in air. Express your answer as a balanced chemical equation. Identify all of the phases in your answer.
Friday, January 25, 2013 at 9:07pm

chemistry
Write a balanced chemical equation for the reaction that occurs when barium carbonate decomposes into barium oxide and carbon dioxide gas when heated.
Friday, January 25, 2013 at 8:16pm

Chemistry
What is the mole fraction of solute in a 3.26 m aqueous solution?
Friday, January 25, 2013 at 5:58pm

chemistry
what is the [OH-] in a solution that contains 0.225g of NaOH in 0.250 L of solution
Friday, January 25, 2013 at 4:24pm

chemistry
If the temperature of a 500.0-g sample of liquid water is raised 2.00c how much heat is absorbed by the water?The specific heat of liquid water is 4.184j/(g*c)
Friday, January 25, 2013 at 3:34pm

Chemistry..
What is the name of ZnCl2O6?
Friday, January 25, 2013 at 3:03pm

chemistry
Tell how to make a 1 M solution of Mg3(PO4)2 and a 0.1 M solution of CaSO4.
Friday, January 25, 2013 at 3:02pm

chemistry quick help!
In the balanced double replacement reaction of calcium chloride CaCl2 and aluminum sulfate Al2(SO4)3, how many grams of calcium sulfate can be produced if you start the reaction with 4.19 grams of calcium chloride and the reaction goes to completion?
Friday, January 25, 2013 at 2:03pm

chemistry
Calcium reacts with water to yield calcium hydroxide and water according to the following equation: Ca + 2H2O ==> Ca(OH)2 + H2 . How many moles of hydrogen will be produced if 3115.8 grams of calcium hydroxide is produced?
Friday, January 25, 2013 at 1:18pm

chemistry
a sample of compound C,H,N and O with a mass of 0.6216 was found to contain 0.1735g C,0.01455g H,0.2024g N.Its molecular mass 129.calculate its epirical and molecular formulas.
Friday, January 25, 2013 at 12:18pm

chemistry
an iron supplement is used to treat anaemia and 50mg of iron 2 is required per tablet.if the iron compound used in the tablet is FeSO4.7H2O,what mass of this compound would be required per tablet to provide the desired amount of iron 2?
Friday, January 25, 2013 at 10:34am

Chemistry
Imagine that a hypothetical life form is discovered on our moon and transported to Earth. On a hot day, this life form begins to sweat, and it is determined that the heat of vaporization of its sweat is 155 cal/g. The scientist observing the extraterrestrial life form also ...
Friday, January 25, 2013 at 10:11am

chemistry
balance the equation c2h4(g)+o2(g)---c(s)+h2o
Friday, January 25, 2013 at 9:51am

chemistry
1-butanol (shown below) burns in the presence of oxygen to give off carbon dioxide and water by the following reaction: C4H9OH + 6 O2 ==> 4 CO2 + 5 H2O If 40.88 mL of 1-butanol burns completely, how many grams of 1-butanol have burned? grams =33.1 bu then Now, How many ...
Friday, January 25, 2013 at 9:08am

chemistry
Calculate the energy of a photon of electromagnetic radiation at each of the following wavelengths.503 nm(wavelength of maximum solar radiation) i need help please!
Friday, January 25, 2013 at 6:40am

Chemistry
Calculate the heat of solution of LiOH if addition of 25.0g of LiOH causes the temperature of 120.0ml of water to rise from 20.0 celcius to 29.0 celcius.
Friday, January 25, 2013 at 6:14am

Chemistry 12
which of the following 0.10M solutions is basic? A LiCl B K3Po4 C NaCLO4 D NH4NO3 Is it C?
Friday, January 25, 2013 at 1:27am

Chemistry 12
define the term strong bronsted lowry acid it is 100% ionized in solution? is that it?
Friday, January 25, 2013 at 1:09am

Chemistry 12
name a compound that acts as a weak base? methanol? define the term weak bronsted-lowry base im not sure how to put this in words, but a weak base is found when you got a strong acid, when your ka is high, kb will be low.
Friday, January 25, 2013 at 12:59am

Chemistry Dr.Bob222==> Take a Look
what is this compound, it has a mf of c6h12o i. imgur. com/gCgw0Hi. png What may be the structure from the IR and H NMR data? This question is bugging me.
Friday, January 25, 2013 at 12:42am

Chemistry 12
The value of Kb for HPO₄²- is? A. 2.2*10^-13 B. 6.2*10^-8 C. 1.6*10^-7 D. 4.5*10^-2 I dont get how to solve this.
Friday, January 25, 2013 at 12:40am

Chemistry 12
The [OH-] of a solution with a PH 5.75 is is it 5.6*10-9M?
Friday, January 25, 2013 at 12:12am

Chemistry
How many moles of bromine are there in a 0.35 mL dichloromethane solution of 10% bromine? Density of Bromine = 3.10g/mL Density of dichloromethane = 1.33g/mL
Thursday, January 24, 2013 at 11:46pm

Chemistry
Hydroxylapatite, Ca10(PO4)6(OH)2, has a solubility constant of Ksp = 2.34 × 10-59, and dissociates according to Ca10(PO4)6(OH)2(s) --> 10Ca2+(aq) + 6PO43-(aq) + 2OH-(aq) Solid hydroxylapatite is dissolved in water to form a saturated solution. What is the ...
Thursday, January 24, 2013 at 11:18pm

chemistry
What is the silver ion concentration in a solution prepared by mixing 385 mL of 0.380 M silver nitrate with 467 mL of 0.409 M sodium chromate? The Ksp of silver chromate is 1.2 × 10-12 I ended up making Ag+ = 2x. = 1.3 x10^-4 Which is incorrect so I'm not sure how to...
Thursday, January 24, 2013 at 11:17pm

Chemistry
2. Suppose that the amount of algae in a pond doubles every 4 hours. If the pond initially contains 90 pounds of algae, how much algae will be in the pond after 12 hours? A.)720 pounds B.)360 pounds C.)1,440 pounds D.)114 pounds I think the answer is D. Please help. Thank You.
Thursday, January 24, 2013 at 10:18pm

Chemistry
Write the chemical equation showing dihydrogen phosphate and hydrogen phosphate conjugate acid-base relationship. Identify the acid and base. Explain how the equilibrium is shifted as buffer reacts with an acid and reacts with a base.
Thursday, January 24, 2013 at 10:14pm

Chemistry
Write the chemical equation showing dihydrogen phosphate and hydrogen phosphate conjugate acid-base relationship. Identify the acid and base. Explain how the equilibrium is shifted as buffer reacts with an acid and reacts with a base.
Thursday, January 24, 2013 at 10:06pm

Chemistry
For melting point determination, what is the optimum rate of heating near the melting point? What are the problems, if the rate of heating is too slow or fast?
Thursday, January 24, 2013 at 9:55pm

Chemistry
Write the chemical equation showing dihydrogen phosphate and hydrogen phosphate conjugate acid-base relationship. Identify the acid and base. Explain how the equilibrium is shifted as buffer reacts with an acid and reacts with a base.
Thursday, January 24, 2013 at 9:40pm

Chemistry
The half-life of C-14 is 5700 years. If it took seven half lives for a sample of C-14 to decay completely, how many years would have gone by?
Thursday, January 24, 2013 at 9:36pm

Chemistry
If a 100.0 gram sample of a radioactive isotope goes through three half-lives, how much of the original radioactive isotope will remain?
Thursday, January 24, 2013 at 9:17pm

Chemistry
Write the chemical equation showing dihydrogen phosphate and hydrogen phosphate conjugate acid-base relationship. Identify the acid and base. Explain how the equilibrium is shifted as buffer reacts with an acid and reacts with a base.
Thursday, January 24, 2013 at 9:14pm

Chemistry
Write the chemical equation showing dihydrogen phosphate and hydrogen phosphate conjugate acid-base relationship. Identify the acid and base. Explain how the equilibrium is shifted as buffer reacts with an acid and reacts with a base.
Thursday, January 24, 2013 at 9:08pm

Chemistry
Write the chemical equation showing dihydrogen phosphate and hydrogen phosphate conjugate acid-base relationship. Identify the acid and base. Explain how the equilibrium is shifted as buffer reacts with an acid and reacts with a base.
Thursday, January 24, 2013 at 9:07pm

Chemistry
What is the density, in grams per liter, of N subscript 2 gas at STP
Thursday, January 24, 2013 at 8:46pm

Chemistry.
Caculate the wavelength of light emitted when each of the following transitions occur in the hydrogen atom. A.) n=3->n=2 B.) n=4->n=3 C.) n=2->n=1 How do you do this. Could you please just show me step by step for atleaset one. Please!
Thursday, January 24, 2013 at 8:44pm

chemistry
What mass of lead (II)chloride would precipitate if a solution containing 8,28 g of lead (II) ions(Pb2+) reacts with excess HCl?
Thursday, January 24, 2013 at 8:44pm

Chemistry
Write the chemical equation showing dihydrogen phosphate and hydrogen phosphate conjugate acid-base relationship. Identify the acid and base. Explain how the equilibrium is shifted as buffer reacts with an acid and reacts with a base.
Thursday, January 24, 2013 at 8:31pm

organic chemistry
what is this compound, it has a mf of c6h12o i. imgur. com/gCgw0Hi. png
Thursday, January 24, 2013 at 8:21pm

Chemistry
a 15ml sample of sulfuric acid was titrated against a solution of .0100 mol per litre of sodium hydroxide. to bring about neutralization, 25.00 ml of sodium hydroxide solution was required. calculate the concentration of the sulfuric acid
Thursday, January 24, 2013 at 7:16pm

Chemistry
The antifreeze in a car is a 50% by weight solution of ethylene glycol, C2H6O2 in a water solvent. Calculate the boiling point and freezing point of this solution. (For H2O, Kb=0.52 C/m Kf= 1.86 C/m I can't even find the formula for this in my book, please help :(
Thursday, January 24, 2013 at 7:13pm

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