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March 28, 2015

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

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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 at 10:13pm

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 at 8:57pm

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 at 8:47pm

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 at 8:02pm

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 at 7:57pm

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 at 7:38pm

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 at 2:35pm

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 at 2:29pm

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 at 2:28pm

Chemistry
An electron has an uncertainty in its position of 507pm. What is the uncertainty in its velocity?
Friday, March 13, 2015 at 10:25am

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 at 9:19am

chemistry
What is the % carbon by weight in 1.7 grams of potassium carbonate (K2CO3)? Answer in units of %.
Friday, March 13, 2015 at 9:17am

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 at 9:15am

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 at 7:40am

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 at 1:53am

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 at 12:46am

chemistry
what's the lewis dot diagram for methanol?
Friday, March 13, 2015 at 12:45am

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 at 12:32am

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 at 11:46pm

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 at 11:45pm

chemistry
What salt results from the neutralization of acetic acid with potassium hydroxide?
Thursday, March 12, 2015 at 11:26pm

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 at 11:24pm

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 at 9:45pm

chemistry
Calculate the volume 2.3g of oxygen gas at 28 degrees celcius and 2.321 atm
Thursday, March 12, 2015 at 9:07pm

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 at 8:36pm

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 at 7:46pm

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 at 6:59pm

Chemistry
what is the VSEPR of NF4+
Thursday, March 12, 2015 at 6:13pm

Chemistry
I forgot to weigh the mass of filter paper and CaC2O4 before oven drying it. What do i do?
Thursday, March 12, 2015 at 5:59pm

Analytical Chemistry
Given a 300 ml solution containing 0.2M H2L+ calculate the pH after the addition of 130.00 ml of 0.6M KOH. -----pH = 9.377 What total volume of KOH must be added to reach pH of 10.00 ---0.386 moles However, I am getting an amount of ml that is way too high, according to the ...
Thursday, March 12, 2015 at 5:55pm

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 ??? pressure is directly proportional to temp in Kelvins. So change temps to K emperature(K) pressure(mm of hg) 283 726 293 750 ...
Thursday, March 12, 2015 at 5:28pm

Chemistry
A pH = 7.6 buffer is needed in the lab. This buffer is made by first dissolving 17.42 g K2HPO4 in 600 mL of water. What is the pH of this salt solution? This solution of course will be too basic becuase we only have the base of the buffer present. What must the value of the ...
Thursday, March 12, 2015 at 5:27pm

Chemistry
Calculate the pH of the the solution that results from titrating 50 mL of 0.6 M NaOCl(aq) with 0.3 M HBr At 0.00 mL of HBr: At 70 mL of HBr: At 100 mL HBr: At 120 mL of HBr
Thursday, March 12, 2015 at 5:26pm

Chemistry
Calculate the pH of the the solution that results from titrating 50 mL of 0.6 M HCN(aq) with 0.2 M NaOH At 0.00 mL of NaOH At 85 mL of NaOH. At 150 mL NaOH. At 160 mL of NaOH
Thursday, March 12, 2015 at 5:25pm

Chemistry
What is the pH of a 150 mL buffer solution containing 0.5 M NaH2PO4 with 0.5 M K2HPO4? Determine the new pH of the solution upon the addition of 10 mL of 1.2 M strong acid to the 150 mL buffer solution above.
Thursday, March 12, 2015 at 5:24pm

Chemistry
what is the pH of a solution created by adding 15.5 g of KClO to 228 mL of 1.08 M HClO(aq).?
Thursday, March 12, 2015 at 5:23pm

chemistry
What salt results from the neutralization of acetic acid with potassium hydroxide?
Thursday, March 12, 2015 at 5:04pm

Chemistry
Calculate the concentration of OH− and the pH value of an aqueous solution in which [H3O+ ] is 0.014 M at 25°C. Is this solution acidic, basic or neutral?
Thursday, March 12, 2015 at 5:01pm

Chemistry help please
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.
Thursday, March 12, 2015 at 4:34pm

chemistry
Initially, 0.600 mol of A is present in a 4.00-L solution. 2A[aq]->2B[aq]+C[aq] At equilibrium, 0.200 mol of C is present. Calculate K.
Thursday, March 12, 2015 at 4:10pm

Chemistry
A chemist reacts 112 g of iron with 72 g of water. State which reactant is the limiting reagent. Calculate what is the maximum yield in grams of Fe3O4 that could be produced in this reaction. For the substance that is not the limiting reagent, calculate the amount in excess.
Thursday, March 12, 2015 at 4:10pm

chemistry
In the reaction O2+2NO->2NO2 what is the ratio of oxygen reacted to nitrogen dioxide produced? Nitrogen monoxide to nitrogen dioxide? We had to calculate the concentration of each, for which I have O2=-1.01x10^-5, NO=-2.03x10^-5 and NO2=2.04x10^-5. I'm not sure how to ...
Thursday, March 12, 2015 at 4:07pm

Chemistry
What volume of .225 M aluminum chloride solution contains 5.0 g solute?
Thursday, March 12, 2015 at 2:43pm

chemistry
How many grams of hydrogen are released by the reaction of 1.00 g of aluminum with excess potassium hydroxide solution assuming 100% yield
Thursday, March 12, 2015 at 12:52pm

chemistry
what volume of a 2.4 mol/L magnesium oxide solution contains 2.3 mol of magnesium oxide?
Thursday, March 12, 2015 at 11:01am

chemistry
how many ml of 0.655 M phosphoric acid solution is required to neutralize 15 ml of 1.284 M NaOH solution, write a balanced chemical equation
Thursday, March 12, 2015 at 10:23am

Chemistry
How much time is required for a sound to travel 1 mile if the air temperature is: 0.0 Degrees Celsius 20.0 Degrees Celsius 40.0 Degrees Celsius 80.0 Degrees Celsius
Thursday, March 12, 2015 at 9:01am

chemistry
is acid rain homogeneous or heterogeneous mixture?
Thursday, March 12, 2015 at 8:28am

chemistry
A 11.0g sample of compound containing only oxygen and carbon produces 3.0g carbon and 8.0g oxygen. Determine the empirical formula of the compound.
Thursday, March 12, 2015 at 8:05am

Chemistry
Calculate the mass of 5.35 mol of iodine
Thursday, March 12, 2015 at 7:45am

Chemistry
I have a question here: What is the definition of bubble-point line? a) The line that shows when the liquid begins to boil/evaporate b) The vapor-mixture liquid region c) Saturated liquid equilibrium line d) None of the above My textbook says it is saturated liquid equilibrium...
Thursday, March 12, 2015 at 1:30am

Chemistry
What is the empirical formula for a compound that is 1.67g Ce and 4.54g I?
Thursday, March 12, 2015 at 12:07am

Chemistry
a solution of methanol, CH3OH, contains 55.0 grams of methanol for every 100. grams of water. what is the molality of the solution? Which is my solvent? And which is my solution? Im confused
Wednesday, March 11, 2015 at 11:57pm

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?
Wednesday, March 11, 2015 at 11:33pm

chemistry
The freezing of water at 0⁰C can be represented as follows: H2O (l) ↔ H2O(s) The density of liquid water is 1.00 g/cm3. The density of ice is 0.92 g/cm3. explain why applying pressure causes ice to melt.
Wednesday, March 11, 2015 at 11:32pm

Chemistry
The Kw of water varies with temperature. Calculate the pH of water at 46⁰C with a Kw = 1.219 x 10-14.
Wednesday, March 11, 2015 at 11:32pm

chemistry
Calculate the hydroxide ion concentration of a solution with pH = 8.25.
Wednesday, March 11, 2015 at 11:10pm

chemistry
explain whether sodium chloride or calcium chloride would be a more effective substance to melt the ice on a slick sidewalk.
Wednesday, March 11, 2015 at 11:06pm

chemistry
Why must the number of electrons lost equal the number of electrons gained in every redox reaction?
Wednesday, March 11, 2015 at 11:03pm

Chemistry help please
You have two sealed jars of water at the same temperature. In the first jar there is a large amount of water. In the second jar there is a small amount of water. how the vapor pressure of water in the first jar compares with the vapor pressure of water in the second jar.
Wednesday, March 11, 2015 at 11:01pm

Chemistry help please
What type of radiation is emitted when K-38 decays into Ca-38?
Wednesday, March 11, 2015 at 10:58pm

chemistry
if 4.75 g of cooper and 3.20 g of sliver are available to react ,what is the limiting reactant
Wednesday, March 11, 2015 at 10:06pm

Chemistry help please
What is the oxidation number of phosphorus in P2O3? O mostly always has a -2 charge, three O's = -6. The two P atoms must balance that charge with +6 since P2O3 overall has no charge. If 2 P = +6, then 1 P = +3. is that right ?
Wednesday, March 11, 2015 at 9:29pm

Chemistry ( I NEED HELP, PLEASE!!!, IM DESPERATE!)
Sodium peroxide reacts vigorously with water to produce sodium hydroxide and oxygen. The unbalanced equation is Na2O2(s) + H2O(ℓ)→ NaOH(aq) + O2(g). What mass of O2 is produced when 81 g of Na2O2 react?
Wednesday, March 11, 2015 at 9:25pm

CHEMISTRY HELPPPP!!!!!!!!!
Consider the decomposition of NH3 (g). 2 NH3 (g) → N2 (g) + 3 H2 (g) The reaction is catalyzed on a surface of either tungsten or osmium. The activation energies for the catalyzed and uncatalyzed reactions are given below. W Ea = 163 kJ/mol Os Ea = 197 kJ/mol No catalyst...
Wednesday, March 11, 2015 at 8:51pm

Chemistry 2
A United Nations toxicologist studying the properties of mustard gas, S(CH2CH2Cl)2, a blistering agent used in warfare, prepares a mixture of 0.675 M SCl2 and 0.973 M C2H4 and allows it to react at room temperature (20.0°C ). SCl2 (g) + 2 C2H4 (g) --> S(CH2CH2Cl)2 (g) ...
Wednesday, March 11, 2015 at 8:36pm

Chemistry( HELP PLEASE, IM DESPERATE!!!)
For the reaction 2CH3OH + 3O2 → 2CO2+ 4H2O, what is the maximum amount of CO2 which could be formed from 13.97 g of CH3OH and 5.45 g of O2? Consider the reaction H3PO4 + 3NaOH → Na3PO4 + 3H2O. How much Na3PO4 can be prepared by the reaction of 3.43 g of H3PO4 with ...
Wednesday, March 11, 2015 at 8:26pm

Chemistry( I NEED HELP, PLEASE!!!!, IM DESPERATE)
What is the limiting reactant when 45.9g of CuO are exposed to 2.57 g of H2 according to the equation CuO(s) + H2(g)−→Cu(s) + H2O(g) ? 1.CuO 2.Unable to determine. 3.H2 4.Neither is limiting.
Wednesday, March 11, 2015 at 8:23pm

Chemistry ( I NEED HELP, PLEASE!!!!, IM DESPERATE)
What mass of water is needed to react com- pletely with the Na2O2?
Wednesday, March 11, 2015 at 8:21pm

Chemistry ( I NEED HELP, PLEASE!!!!, IM DESPERATE)
Sodium peroxide reacts vigorously with water to produce sodium hydroxide and oxygen. The unbalanced equation is Na2O2(s) + H2O(ℓ)→ NaOH(aq) + O2(g). What mass of O2 is produced when 81 g of Na2O2 react?
Wednesday, March 11, 2015 at 8:19pm

chemistry
explain whether sodium chloride or calcium chloride would be a more effective substance to melt the ice on a slick sidewalk.
Wednesday, March 11, 2015 at 7:35pm

chemistry
why water expands when it freezes? Water expands when it freezes because it starts to bend. when all the water molecules are in this hexagonal structure, the same amount of water takes up more space than when the molecules are randomly arranged. For example- In the ocean ...
Wednesday, March 11, 2015 at 7:33pm

Chemistry
You have two sealed jars of water at the same temperature. In the first jar there is a large amount of water. In the second jar there is a small amount of water. how does the vapor pressure of water in the first jar compares with the vapor pressure of water in the second jar.
Wednesday, March 11, 2015 at 7:20pm

chemistry
how perspiration helps keep you cool on a hot day.? Perspiration keep’s you cool on a hot day because your really steamy and sweaty. You have no energy or strength to move. Your sweat drys up from your skin taking a little bit of your body heat with it. Is this good ?
Wednesday, March 11, 2015 at 7:17pm

Chemistry
For the reaction 2CH3OH + 3O2 → 2CO2+ 4H2O, what is the maximum amount of CO2 which could be formed from 13.97 g of CH3OH and 5.45 g of O2? Answer in units of g. Consider the reaction H3PO4 + 3NaOH → Na3PO4 + 3H2O. How much Na3PO4 can be prepared by the reaction of...
Wednesday, March 11, 2015 at 7:13pm

Chemistry
What is the limiting reactant when 45.9g of CuO are exposed to 2.57 g of H2 according to the equation CuO(s) + H2(g)−→Cu(s) + H2O(g) ? 1.CuO 2.Unable to determine. 3.H2 4.Neither is limiting.
Wednesday, March 11, 2015 at 7:03pm

chemistry
why gasoline wouldn't dissolve in water ?
Wednesday, March 11, 2015 at 6:55pm

Chemistry
What happens when Potassium Oxide is left on a watch glass and exposed to air?
Wednesday, March 11, 2015 at 4:31pm

Chemistry HW!!!
1. If I dilute 75 mL of 0.50 M CaF2 solution to a final volume of 375 mL, what will be the molarity of the resulting solution? 2. What will be the final volume of the solution be if I start with a 250 mL of 1.38 M MgCl2 solution to make a solution with a concentration of 0.30 ...
Wednesday, March 11, 2015 at 4:30pm

chemistry
how many molecules are in 5.5 moles of oxygen gas? How many atoms are in this quantity of gas? I used dimensional analysis and did: 5.5 mol. of oxygen x 6.02x10^23 molecules/1 mol of oxygen I got 3.3x^24 molecules of oxygen How do I find the # of atoms? I know that there are 2...
Wednesday, March 11, 2015 at 4:23pm

Chemistry
Can someone please help me figure out whether aqueous sodium sulfite is acidic or basic? I know it is a salt produced from sodium hydroxide and sulfur dioxide.
Wednesday, March 11, 2015 at 4:06pm

Chemistry
3.05 g of hydrated copper sulfate produce 1.94 g of anhydrous salt. Assuming complete removal of water of crystallisation, determine the formula of hydrated copper sulfate.
Wednesday, March 11, 2015 at 3:35pm

chemistry
when 5g of impure sample of CH4 is completely combusted, 9g of H2O was produced.what is the percentage purity of the sample of CH4
Wednesday, March 11, 2015 at 2:19pm

Chemistry
Calculate the volume at which pH = pKa if 30.00mL of weak acid with a concentration of 0.0955M is titrated against a strong base with a concentration of 0.1233M.
Wednesday, March 11, 2015 at 11:25am

Chemistry
High-pressure liquid chromatography (HPLC) is a method used in chemistry and biochemistry to purify chemical substances. The pressures used in this procedure range from around 500 kilopascals (500,000 Pa ) to about 60,000 kPa (60,000,000 Pa ). It is often convenient to know ...
Wednesday, March 11, 2015 at 11:24am

Chemistry
Based on the average number of moles of IO3- in your samples, and the initial volume of those samples, what is the solubility of Ca(IO3)2 in mol/L of the saturated solution in 0.01 M KIO3? My average molarity was: .000092 My sample volume was: 5ml or .005 L
Wednesday, March 11, 2015 at 3:41am

Chemistry
Replace names by formulas and indicate oxidation and reduction agents (do not balance reactions). copper(ll) oxide + CH30H (Iq) ->CH20 (Iq) + cu (s)
Wednesday, March 11, 2015 at 12:55am

Chemistry
Find density of C02 at room temperature and normal pressure.
Wednesday, March 11, 2015 at 12:37am

Chemistry
At a deep-sea station 200. m below the surface of the Pacific Ocean, workers live in a highly pressurized environment. How much gas at STP must be compressed on the surface to fill the underwater environment with 2 × 107 L of gas at 22 atm? Assume that temperature ...
Tuesday, March 10, 2015 at 10:37pm

Chemistry
Are acids or bases suppose to react with carbonates?
Tuesday, March 10, 2015 at 9:37pm

chemistry
10 l of a solution containing 1.5 moles of HI
Tuesday, March 10, 2015 at 9:08pm

Chemistry
a solution of 25 ml of HCL is neutralized by 42.5 ml of 0.10 M concentration of NaOH.Need to write a balanced equation for the reaction
Tuesday, March 10, 2015 at 8:42pm

Chemistry
Find the Density of xenon of STP
Tuesday, March 10, 2015 at 8:33pm

Chemistry
Find temperature of 20.0g of nitrogen that occupies volume of 500.0ml at pressure 0.45 bar.
Tuesday, March 10, 2015 at 8:31pm

chemistry
Find volume of carbon dioxide occupied by 1.0g of CO2 at 0 degrees Celsius and pressure 25.0 torr.
Tuesday, March 10, 2015 at 8:29pm

Chemistry
Find pressure exerted by 2.0g of helium enclosed in a 100.0 ml container at 25 degrees Celsius
Tuesday, March 10, 2015 at 8:26pm

Chemistry
Explain Why some ionic compounds are soluble in water. Explain why non-ionic compounds, such as ethanol or sugar are soluble in water. Explain what a saturated solution.
Tuesday, March 10, 2015 at 8:15pm

Chemistry
What is the pH of a solution prepared by mixing 500mL of 2.0M HCN (Ka= 4.9x10^-10) with 500mL of 1.0 M KOH?
Tuesday, March 10, 2015 at 8:13pm

Chemistry
How to prepare 250ml of 0.2 M hydrochloric acid from 2.5 M hydrochloric acid.
Tuesday, March 10, 2015 at 8:11pm

Chemistry
A student mixes 5.0 mL of 0.00200 M Fe(NO3)3 with 5.0 mL 0.00200 KSCN. She finds that the concentration of FeSCN2+ in the equilibrium mixture is 0.000125 M. Follow these steps to determine the corresponding experimental value of Kc for the reaction of Fe3+ and SCN– to ...
Tuesday, March 10, 2015 at 8:08pm

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