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October 21, 2014

# Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

chemistry
when ch3cooh, nahco3 and as2o3 is heated ,what product will be formed?
Saturday, September 7, 2013 at 9:34am

Chemistry
If 23.7g of C8H18 are combusted, what mass of water will be produced?
Saturday, September 7, 2013 at 7:41am

chemistry
Mno4- + So3-2 = Mno2 + sO4-2 (OH-) solve this redox reaction and give me the method also
Saturday, September 7, 2013 at 3:04am

chemistry assignment
how can i find the standard rf values of food dyes ?
Saturday, September 7, 2013 at 1:19am

Chemistry
The normality of 0.3 M phosphorus acid (H3PO3) is.......
Saturday, September 7, 2013 at 12:38am

Chemistry stochimetry2
The volume strength of 1.5 N H2O2 is.......
Saturday, September 7, 2013 at 12:21am

chemistry
Convert 34.5 in2 to cm2. Report the answer to the correct number of significant figures. (1 inch = 2.54 cm is an exact or defined conversion.)
Friday, September 6, 2013 at 2:37pm

chemistry
An experiment requires 13.0$${\rm g}$$ of cyclohexane, whose density at 25 $$^\circ {\rm C}$$ is 0.7781 $${\rm g/mL}$$. What volume of cyclohexane should be used?
Friday, September 6, 2013 at 11:27am

chemistry
What volume of a 2.5 M stock solution of acetic acid (HC2H3O2) is required to prepare 100.0 milliliters of a 0.50 M acetic acid solution?
Friday, September 6, 2013 at 9:07am

Organic Chemistry
Is ethyl cyclohexane optically active?
Thursday, September 5, 2013 at 11:04pm

Organic Chemistry
How many stereoisomers are possible for each of the following structures? Draw them, and name each by the R-S and E-Z conventions a) 4-methyl-2,5-heptadiene b) 1,2,5-trichloro-3-hexene
Thursday, September 5, 2013 at 9:31pm

Organic Chemistry
How many stereoisomers are possible for each of the following structures? Draw them, and name each by the R-S and E-Z conventions
Thursday, September 5, 2013 at 9:28pm

Organic Chemistry
Place these in order of decreasing priority according to the R-S convention a) H, CL, Br, CH3 B) OH, CH3, CH2CL, CH3CH2 C) CH3, CH2CH3, CL, c6H5
Thursday, September 5, 2013 at 9:26pm

Organic Chemistry
Which of the following substances can exist in an optically active form a) 1,3 dibromopropane b) ethyl cyclohexane c) 3 ethylpentane
Thursday, September 5, 2013 at 9:24pm

chemistry
An ore contains Fe3O4 and no other iron. The iron in a 38.9-gram sample of the ore is all converted by a series of chemical reactions to Fe2O3. The mass of Fe2O3 is measured to be 12.5 g. What was the mass of Fe3O4 in the sample of ore? Please show all work, not just the ...
Thursday, September 5, 2013 at 7:50pm

chemistry
A 76.00-pound flask of mercury costs $151.50. The density of mercury is 13.534 g/cm3. What is the price of one gram of mercury? Thursday, September 5, 2013 at 4:59pm chemistry 1.00 g of aniline and an excess of 2 M sodium hydroxide are mixed in a conical flask, after which 1.20 grams benzoyl chloride is added and the flask shaken vigorously. When water is added after reaction bensaniliden falls out of the piston bottom. The solid phase is separated... Thursday, September 5, 2013 at 4:15pm chemistry 2,4,6-Trinitroanilin can be prepared by nitration of p-nitroaniline with nitrate ions in the acidic solution. Chemical engineer sounds 0.50 grams of p-nitroaniline (dissolved in sulfuric acid) to react with 0.60 g of sodium nitrate (dissolved in sulfuric acid). Which reactant ... Thursday, September 5, 2013 at 4:13pm chemistry 101 I have a question that I am not sure how to even start. A 15.0 g sample of a liquied has a density of 0.875 g/ml a what is the voulme in milliters of the liquid? use conversion factors to calculate answer b. What mass, in grams of the liquid is in 34.6ml of the liquid? I am ... Thursday, September 5, 2013 at 3:58pm Chemistry Benzoic acid and quinine are dissolved in a solution of dichloromethane. (benzoic acid pKa = 4.2; quinine pKa = 8.5) a) Besides the normal neutral forms for benzoic acid and quinine, will there be any other chemical form(s) present in the dichloromethane solution? a) What ... Thursday, September 5, 2013 at 4:16am Chemistry, stochiometry2 The no. Of moles of KMnO4 that will be needed to react with one mole of sulphite ion in acidic solution is....... Thursday, September 5, 2013 at 3:44am chemistry A 1.24 gram sample of potassium chlorate was heated with manganese dioxide until no addition reaction was visible. THe potassium chloride residue was found to be .72 grams. What was the mass of the oxygen evolved in the experiment? If there is a balanced equation, if you could... Thursday, September 5, 2013 at 1:41am Chemistry A solution of an unknown base has a concentration of 0.250M, and a pH of 12.72. Calculate Kb for this base. Thursday, September 5, 2013 at 1:28am chemistry determine the mass of a 1.75 cm piece of Mg if 30 am =.42 g? Wednesday, September 4, 2013 at 7:24pm chemistry determine the molecular mass of magnesium oxide? Wednesday, September 4, 2013 at 7:23pm chemistry for a reversible reaction if the concentration of reactant are doubled aad a definate tempreture then equilibrium constant will Wednesday, September 4, 2013 at 12:00pm Organic Chemistry My original question was that I wished to dissolve 100mg of caffeine powder in oil but could not do it as caffeine was not soluble in oil. The answer was to dissolve soap in the oil first, then the caffeine. I've done some research and I propose to dissolve sodium lauryl ... Wednesday, September 4, 2013 at 11:18am Chemistry -A sample consist 90% NaOH and 10% CaO,whats the concentration of NaOH in the solution of this 3g sample,dissolved in 250cm3. -How many cm3 of H2SO4 with concentration of 0.255M are needed for titration of 100cm3 of this solution Wednesday, September 4, 2013 at 8:28am chemistry Polycarbonate plastic has a density of 12 g/cm3. A photo frame is contructed feom two 3 I n sheets of polycarbonate. Each sheet measures 28 cm by 22 cm. What is the mass of the photo frame Tuesday, September 3, 2013 at 11:57pm Chemistry Suppose you have two 100mL graduated cylinders. In each cylinder, there is 36.0mL of water. You also have two cubes: one is lead, and the other is aluminum. Each cube measures 2.40cm on each side. Tuesday, September 3, 2013 at 10:42pm Chemistry Suppose you have two 100mL graduated cylinders. In each cylinder, there is 36.0mL of water. You also have two cubes: one is lead, and the other is aluminum. Each cube measures 2.40cm on each side. Tuesday, September 3, 2013 at 10:41pm Chemistry II What is the molar concentration of a solution produced by dissolving 1.234 g (NH4)2CrO4 in water and diluting to a total final volume of 300.0 ml? (mass of {NH4}2CrO4 is 152.03 g/mol). Tuesday, September 3, 2013 at 10:35pm chemistry How many liters is 5.8 moles of neon (Ne) at STP? Tuesday, September 3, 2013 at 7:17pm Chemistry a chemist needs 2.00 grams of a liquid compound witha density of 0.785 g/cm^3 density. what volume of compund is required? Tuesday, September 3, 2013 at 2:45pm Chemistry a chemist needs 2.00 grams of a liquid compound witha density of 0.785 g/cm^3 density. what volume of compund is required? Tuesday, September 3, 2013 at 2:30pm CHEMISTRY!! D: 1. A sample of gas under a pressure of 622 kPa has a volume of 233 cm3. The pressure is increased to 988 kPa, while the temperature remains constant. What volume will the gas occupy at this pressure? 2. The pressure exerted by a gas is 2.0 atm while it has a volume of 350 cm3... Tuesday, September 3, 2013 at 1:31pm URGENT Science question 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 this career? biomedical science and meteorology oceanography and paleontology chemistry and biology physics and computer science*** Am I... Tuesday, September 3, 2013 at 1:03pm CHEMISTRY HELP! D; 1._____Mg + _____N2 ---> _____Mg3N2 2. _____KNO3(s) ---> _____KNO2(s) + _____O2(g) Tuesday, September 3, 2013 at 12:06pm chemistry Upon decomposition, one sample of magnesium fluoride produced 1.65kg of magnesium and 2.58kg of fluorine. A second sample produce 1.38kg of magnesium. How much fluorine (in grams) did the second sample produce? Tuesday, September 3, 2013 at 1:29am Chemistry Predict the bond angles in each of the following molecules: ^+^CH3 and Cl4Si My first guesses for 120 and 109.5 degrees, but not too sure Monday, September 2, 2013 at 11:41pm chemistry an aspirin contains .324 g of aspirin. how many pounds of aspirin are in a 500 aspirin of bottle Monday, September 2, 2013 at 8:44pm AP Chemistry A 44.6 g of iron ore is treated as follows. The iron in the sample is all converted by a series of chemical reactions to Fe2O3. The mass of Fe2O3 is measured to be 10.1 grams. What was the percent iron in the sample of ore? Answer in units of % Monday, September 2, 2013 at 6:58pm chemistry A solution is 40% acetic acid by mass. The density of this solution is 1.049 g/mL. Calculate the mass of pure acetic acid in 170 mL of this solution at 20 C. Answer in units of g The density of a solution of sulfuric acid is 1.29 g/cm3 and it is 38.1% acid by mass. What volume... Monday, September 2, 2013 at 6:56pm AP Chemistry Where did you get the two that you multiplied by the atomic mass of iron? Monday, September 2, 2013 at 6:54pm College chemistry math ratio problem Earlier you determined that the proper ratio of packages of buns, packages of patties, and jars of pickles is 3:2:4. If you want to feed at least 540 people, but also maintain the proper ratio, what minimum number of packages of buns, packages of patties, and jars of pickles ... Monday, September 2, 2013 at 6:20pm AP Chemistry A 37.5 g sample of iron ore is treated as follows. The iron in the sample is all converted by a series of chemical reactions to Fe2O3. The mass of Fe2O3 is measured to be 17.8 g. What was the mass of iron in the sample of ore? Answer in units of g Monday, September 2, 2013 at 5:39pm Chemistry How many grams of a stock solution that is 87.0 percent H2SO4 by mass would be needed to make 200 grams of a 35.5 percent by mass solution? Show all of the work needed to solve this problem. Monday, September 2, 2013 at 5:39pm Chemistry Please tell me if my answers are right. Suppose that a series of measurements have shown that the mean mass of an object is 122.4g with a standard deviation of 1.3g. How many significant figures are justified in the mean and how would you report the most probably mass of the ... Monday, September 2, 2013 at 5:34pm Chemistry A block of metal has a width of 3.2 cm, a length of 17.1 cm, and height of 5.8cm . Its mass is 1.5kg . Calculate the density of the metal. Monday, September 2, 2013 at 5:18pm Analytical chemistry What is a pH of 20 mL of 0.08 M NH3 added to 40 mL of 0.04 M HCl? NH3 + HCl = NH4+ + Cl- c(NH3)=(0.02L * 0.08M)/0.06L= 0.02667 M c(HCl)=(0.04L * 0.04M)/0.06L= 0.02667 M c(NH4+)=c(HCl) Kb=[NH4+][OH-]/[NH3] Kb=1.76*10^(-5) So i tried to calculate it like this: Kb=[OH-] pOH=4.... Monday, September 2, 2013 at 8:11am chemistry Calculate the amount of heat required to completely sublime 76.0g of solid dry ice (CO2) at its sublimation temperature. The heat of sublimation for carbon dioxide is 32.3 kJ/mol. Sunday, September 1, 2013 at 9:40pm chemistry A thief uses a can of sand to replace a solid gold cylinder that sits on a weight-sensitive, alarmed pedestal. The can of sand and the gold cylinder have exactly the same dimensions (length = 23cm and radius = 3.9cm ). Sunday, September 1, 2013 at 4:53pm chemistry A block of metal has a width of 3.2 cm, a length of 17.1 cm, and height of 3.9cm . Its mass is 1.3kg . Calculate the density of the metal. Sunday, September 1, 2013 at 2:36pm Chemistry If lava can flow 1.5 km in 45 minutes, how do I figure how long it takes to go 5.0 km. It traveled 33 m per minute. Sunday, September 1, 2013 at 2:28pm Chemistry the mass of cylinder one is 1.35 times the mass of cylinder two, and the volume of cylinder one is 0.792 times the volume of cylinder two. If the density of cylinder one is 2.70 g/cm3 what is the density of cylinder two? THIS QUESTION HAS ME GOING CRAZY!! Sunday, September 1, 2013 at 11:19am chemistry how many grams of oxygen are required to burn completely 570g of octane? Sunday, September 1, 2013 at 12:18am AP Chemistry A 40.3 g of iron ore is treated as follows. The iron in the sample is all converted by a series of chemical reactions to Fe2O3. The mass of Fe2O3 is measured to be 10.5 grams. What was the percent iron in the sample of ore? Answer in units of % Friday, August 30, 2013 at 9:52pm AP Chemistry An ore contains Fe3O4 and no other iron. The iron in a 40.93 gram sample of the ore is all converted by a series of chemical reactions to Fe2O3. The mass of Fe2O3 is measured to be 30.7 grams. What was the percent Fe3O4 in the sample of ore? Answer in units of % Friday, August 30, 2013 at 9:32pm AP Chemistry Sulfuric acid (H2SO4)is prepared commercially from elemental sulfur using the contactprocess. In a typical sequence of reactions,the sulfur is first burned:S + O2→SO2,then it is converted to SO3 using a catalyst:2SO2+O2→2SO3.The resulting SO3 is reacted with water ... Friday, August 30, 2013 at 8:41pm AP Chemistry A 28.4858 g sample of impure magnesium carbonate was heated to complete decomposition according to the equation MgCO3(s)→MgO(s) + CO2(g).After the reaction was complete, the solid residue (consisting of MgO and the original impurities) had a mass of 17.3014 g. Assuming ... Friday, August 30, 2013 at 8:30pm AP Chemistry An ore contains Fe3O4 and no other iron. The iron in a 36.5-gram sample of the ore is all converted by a series of chemical reactions to Fe2O3. The mass of Fe2O3 is measured to be 26 g. What was the mass of Fe3O4 in the sample of ore? Answer in units of g Friday, August 30, 2013 at 7:31pm Chemistry A farmer applies 1400.0 kg of a fertilizer that contains 10.0% nitrogen to his fields each year. fifteen (15.0%) percent of the fertilizer washes into a river that runs through the farm. If the river flows at an average rate of 0.410 cubic feet per second, what is the ... Friday, August 30, 2013 at 6:24pm chemistry Avogadro number amole vitamin c has a mass of 176g,if you ingest 4.8 x10 the8th power carbon atoms what is the mass in mg? Friday, August 30, 2013 at 5:46pm Chemistry Why does a pound of feathers float, but a pound of lead sink? Is it because of how dense each group is? Thursday, August 29, 2013 at 10:54pm chemistry You add 6.4g g of iron to 27.80mL mL of water and observe that the volume of iron and water together is 28.61mL mL . Calculate the density of iron. Thursday, August 29, 2013 at 10:52pm Chemistry Styrene is a hydrocarbon. If .438 g of the compound is burned and produces 1.48 g CO2 and .303 g of H2O what is the empirical formula of the compound? Thursday, August 29, 2013 at 10:21pm AP Chemistry A 12 g sample of iron ore is treated as follows. The iron in the sample is all converted by a series of chemical reactions to Fe2O3. The mass of Fe2O3 is measured to be 27.6 g. What was the mass of iron in the sample of ore? Answer in units of g Thursday, August 29, 2013 at 9:15pm CHEMISTRY HELP! D; 1.Br2(g) + ___H2O(l) + ___SO2(g) ---> ___HBr(aq) + ___H2SO4(aq) Thursday, August 29, 2013 at 7:27pm chemistry Suppose you are asked to find the area of a rectangle that is 2.1-cm \rm cm wide by 5.6-cm \rm cm long. Your calculator answer would be 11.76 cm 2 \rm cm^2 . Now suppose you are asked to enter the answer to two significant figures. (Note that if you do not round your answer to... Thursday, August 29, 2013 at 1:14pm Chemistry Heat 1kg of CaCO3, get 560g of CaO. Write the reactant equations and solve the mass of CO2 that born. The CaO is 100% pure. Anyone help me, pls? Thursday, August 29, 2013 at 8:48am chemistry If 51J of heat is added to an aluminum can with a mass of 23.0g , what is its temperature change? Specific heat capacity of aluminum is 0.903 J/g∘C. Thursday, August 29, 2013 at 12:42am chemistry If 51J of heat is added to an aluminum can with a mass of 23.0g , what is its temperature change? Specific heat capacity of aluminum is 0.903 J/g∘C. Thursday, August 29, 2013 at 12:40am CHEMISTRY HELP! D; Balancing Chemical Equations; How would you solve this? 1.Br2(g) + ___H2O(l) + ___SO2(g) ---> ___HBr(aq) + ___H2SO4(aq) Wednesday, August 28, 2013 at 8:51pm Chemistry I cannot figure out the equation and answer to the following. Can someone help please. A 25.0 mL solution of HCl has been spilled. It took 21.8 mL of saturated 2.5 M NaOH to neutralise the acid. What was the molar concentration of the acid? Wednesday, August 28, 2013 at 7:41pm Chemistry 1. Hydrogen gas combines with oxygen gas to yield water. if 15 g O2 is present in the reaction, compute how much water will be produced. 2. Ten (10)grams methane gas combines with oxygen gas to form water and carbon dioxide. How much water is produced from the given reaction? ... Wednesday, August 28, 2013 at 10:24am chemistry If 6 moles 735 of KCLO3 were used,what weight of oxygen in grams would obtained? Tuesday, August 27, 2013 at 10:25pm Chemistry What is the empirical formula of a compound that is 14g calcium, 11g oxygen, and 0.7g hydrogen? A. CaOH B. Ca(OH)2 C. Ca2OH2 D. CaO2H Tuesday, August 27, 2013 at 9:29pm Chemistry Oops I posted the right question but wrong answer options... What mass of propane (C3H8) is needed to produce 346g carbon dioxide in the following reaction? C3H8(g)+5O2(g)->3CO2(g)+4H2O(g) A. 346g C3H8 B. 115g C3H8 C. 5075g C3H8 D. 1.86g C3H8 Tuesday, August 27, 2013 at 9:26pm Chemistry What mass of propane (C3H8) is needed to produce 346g carbon dioxide in the following reaction? C3H8(g)+5O2(g)->3CO2(g)+4H2O(g) A. 68.8gS B. 3.07gS C. 13.5gS D. 41.0gS Tuesday, August 27, 2013 at 9:17pm Chemistry Check? Balance Chemical Equations; 1. C2H6(g)+O2(g)---->H2O(g)+CO2(g) Answer: 2C2H12(g)+2O7---->H12O6+2C2+O8 Tuesday, August 27, 2013 at 7:40pm ACT Math Of the 60 students in a school, 24 are currently studying chemistry. Exactly 16 of the girls in the school are not currently studying chemistry. The number of girls in the school is 33. How many boys are currently studying chemistry? Correct answer is 17. How did they get that... Tuesday, August 27, 2013 at 1:59pm Chemistry How much solid product formed with 30ml of NaOH and 40mL of NiCl2? I'm not really sure how to go about this? Monday, August 26, 2013 at 8:58pm chemistry determine the mass of CO2 produced when 51.2 g of CaO is reacted with 50.0 g of C according to the unbalanced equation CaO + C --------CaC2 =CO2 Monday, August 26, 2013 at 8:37pm chemistry in the reaction of magnesium metal with hydrochloric acid to produce magnesium chloride and hydrogen gas. If 4.59 mol of magnesium and 4.59 mol of hydrochloric acid are reacted, how many moles of magnesium chloride are produced ? Monday, August 26, 2013 at 8:34pm Chemistry II Consider the following balanced chemical equation: 3(NH4)2CrO4 + 4Al + 24HCl --> 3CrCl2 + 6NH4Cl + 4AlCl3 + 12H2O. a) How many moles of HCl would be required for the reaction of 0.0123 moles Al? b) How many grams Al would be required for the reaction of 2.00g (NH4)2CrO4? ... Monday, August 26, 2013 at 12:04am Chemistry II An analgesic mixture is 37.5% aspirin by mass. How many grams of the mixture are needed to provide 325 mg aspirin. Make sure to show your work. Monday, August 26, 2013 at 12:01am Chemistry Earth's oceans have an average depth of 3800 m, a total area of 3.63 108 km2, and an average concentration of dissolved gold of 5.8 10-9 g/L. (a) How many grams of gold are in the oceans? (b) How many cubic meters of gold are in the oceans? Assuming the price of gold is$...
Sunday, August 25, 2013 at 4:42pm

Chemistry
0.2 Faradays of electricity were passed through solutions of sulphuric acid. Calculate the volume of hydrogen evolved at s.t.p in sulphuric acid.
Saturday, August 24, 2013 at 3:13pm

Chemistry :)
How does intermolecular force of attraction is responsible for a change of state?
Saturday, August 24, 2013 at 4:26am

Chemistry
A mixture of miscible liquids containing 6 moles of A and 4 moles of B is distilled 1 atm (760 mm Hg) of pressure. The initial distillate was analyzed and found to contain 20 mole percent A and 80 mole percent B. a.) What are the partial vapor pressures of A and B in the ...
Friday, August 23, 2013 at 8:46pm

Chemistry
At 80 degrees Celsius, the vapor pressure of pure liquids x, y and z are 385, 190 and 66 mm Hg. what pressure must be exerted on the surface of the solution containing one mole of x, three moles of y, and two moles of z for the boiling point to begin at 80 degrees Celsius?
Friday, August 23, 2013 at 8:36pm

Chemistry
At 80 degrees Celsius, the vapor pressure of pure liquids x, y and z are 385, 190 and 66 mm Hg. what pressure must be exerted on the surface of the solution containing one mole of x, three moles of y, and two moles of z for the boiling point to begin at 80 degrees Celsius?
Friday, August 23, 2013 at 8:36pm

Chemistry
How does intermolecular force of attraction is responsible for a change of state?
Friday, August 23, 2013 at 1:14pm

chemistry
my ques is 2Fe2S3+3O2+6H2O-4Fe(OH)3+6S THIS REACTION WRIGHT ,WRONG PLZ JUST REPLY I AM WAIT FOR YOUR ANSWER.
Friday, August 23, 2013 at 12:57pm

Chemistry
A sample of iron weighing 15.0 g was heated with potassium chlorate (KClO3) in an evacuated container. The oxygen generated from the decomposition of KClO3 converted some of the Fe to Fe2O3. If the combined mass of Fe and Fe2O3 was 17.9g,calculate the mass of Fe2O3 formed and ...
Thursday, August 22, 2013 at 10:30pm

chemistry
describe the detailed procedure of how to prepare 500 ml of 1M of sodium acetate solution.
Thursday, August 22, 2013 at 7:37pm

chemistry
A sample of naphthalene (C10H8) that has a mass of 0.7200 g is burned in a bomb calorimeter. The mass of the calorimeter is 1.580 kg, and its specific heat is 2.55 J/(g °C). As a result of the reaction, the temperature of the calorimeter increases from 22.00°C to 29.3&...
Thursday, August 22, 2013 at 5:59pm

Chemistry Check?
1. _____C2H6(g) + _____O2(g) ---> _____H2O(g) + _____CO2(g) Is my answer right? = 2C2H12(g)+2O7---> H12O6+2C2O8
Thursday, August 22, 2013 at 1:52pm

Chemistry
Having obtained the voume of the flask, she emptied the flask, dried it and filled it with an unknown whose density she wished to determine. The mass of the stoppered flask when completely filled with liquid was 56.796g. Find the density of the liquid.
Thursday, August 22, 2013 at 1:27pm

chemistry Pleae
C7H14O2 + NaOH What will this combination make? and can it be balanced?
Thursday, August 22, 2013 at 9:16am

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