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October 23, 2014

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

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chemistry
A sample of the male sex hormone testosterone, C19H28O2, contains 4.09 1021 hydrogen atoms What is the mass of this sample in grams? i got 0.0697g but its wrong
Sunday, September 30, 2012 at 5:05pm

chemistry
How to balance simple oxidation-reduction reactions by the half-reaction method. Mg (s) + N2 (g)= Mg3N2 (s)
Sunday, September 30, 2012 at 5:02pm

chemistry
A piston has an external energy of 8.00atm. How much work has been done if the cylinder goes from volume of 0.140 liters to 0.450 liters.
Sunday, September 30, 2012 at 3:45pm

Chemistry
What is the total mass (in grams) of O2 in a room measuring (20.0 5.0 11.0) ft3 if the air in the room is at STP and contains 20.95% O2?
Sunday, September 30, 2012 at 1:07pm

chemistry
The metabolic oxidation of glucose, C6H12O6, in our bodies produces CO2, which is expelled from our lungs as a gas. C6H12O6(aq) + 6 O2(g) → 6 CO2(g) + 6 H2O(l) Calculate the volume of dry CO2 produced at body temperature (37°C) and 0.980 atm when 25.5 g of glucose is...
Sunday, September 30, 2012 at 1:07pm

chemistry
A set of bookshelves rests on a hard floor surface on four legs, each having a cross-sectional dimension of 3.9 6.5 cm in contact with the floor. The total mass of the shelves plus the books stacked on them is 260. kg. Calculate the pressure in pascals exerted by the shelf ...
Sunday, September 30, 2012 at 1:06pm

chemistry
Water from a city well is analyzed and found to contain 25 mg/L of (HCO3)^- and 35 mg/L of (CO3)2^-. Calculate the alkalinity of the water as CaCO3.
Sunday, September 30, 2012 at 12:08pm

Chemistry
I'm looking for the moles, using the given amount of atoms. i was given 3.01 x 10^23 atoms of Ag the answer I got was 18.1 x 10^23 is this correct?
Sunday, September 30, 2012 at 1:09am

physical chemistry
2 liters of N2 at 0 degree Celsius and 5 atm pressure are expanded isothermally against a constant pressure of 1 atm until the pressure of the gas is also 1 atm. Assuming the gas to be ideal, what are the values of work,delta E, delta H, and q for the process?
Saturday, September 29, 2012 at 11:10pm

physial chemistry
a weight of 1000g falls freely to a platform from a height of 10 meters. What amount of heat will be evolved when the weight strikes the platform?
Saturday, September 29, 2012 at 10:11pm

physical chemistry
piston whose area is 60 cm2 moves through a distance of 20 cm against a pressure of 3 atm. calculate the work done in joules and calories
Saturday, September 29, 2012 at 10:08pm

Chemistry
Use activity coefficients to find the concentration of hydrogen ions in a solution of 70.0 mM butanoic acid and 0.1 M NaCl. The ionization constant of butanoic acid is Ka = 1.52 × 10-5. Take the size of C3H7COO– to be 500 pm.
Saturday, September 29, 2012 at 9:14pm

chemistry
A STUDENT STUDYING THE FE+3- HSCN equilibrium put into a test tube 10.00ml of 2.00 x 10-3 M Fe(NO3)3 with 10.0 mL of 2.00 x 10-3 M HSCN.THE H+ in the resulting solution was manteined at 0.500.By spectrophotometric analysis of the equilibrium solution, the equilibrium ...
Saturday, September 29, 2012 at 8:15pm

Chemistry
The Ka of a monoprotic weak acid is 3.39 × 10-3. What is the percent ionization of a 0.125 M solution of this acid? I just do not know where to even start...
Saturday, September 29, 2012 at 8:13pm

Chemistry
A block of metal has a width of 3.2 cm , a length of 17.1cm , and height of 5.8cm . Its mass is 1.5kg . Calculate the density of the metal.
Saturday, September 29, 2012 at 7:19pm

Chemistry
The rate constant for a certain reaction is = 8.00×10−3 . If the initial reactant concentration was 0.400 , what will the concentration be after 16.0 minutes?
Saturday, September 29, 2012 at 6:05pm

Chemistry
How many milliliters of a 0.81 M HCl solution are needed to react completely with 2.2 g of zinc to form zinc(II) chloride?
Saturday, September 29, 2012 at 5:06pm

chemistry
How many hydrogen atoms are present in 1.02 mg of aspartame? I already got that there are 2.08e18 molecules of aspartame in 1.02mg of aspartame but i am not sure how to find how many atoms of hydrogen there are
Saturday, September 29, 2012 at 4:38pm

chemistry
How to solve titration problem for HC2H3O2 + NaOH= NaC2H3O2 + H2O The M of NaOH= 0.427 The volume of NaOH= 17.30mL 10.00mL of acid The second titration calculation is: The M of NaOH= 0.427 The volume of NaOH=34.60mL 20.00mL of acid
Saturday, September 29, 2012 at 2:47pm

chemistry
Ariel found the density of an unknown solid to be 24.3 g/cm3. Her teacher told her that something must have gone wrong with her measurements because her percent error was 30.0% too high. What was the actual or accepted density of her unknown solid?
Saturday, September 29, 2012 at 1:57pm

chemistry
In industrial plants, what specific type of oil is used as heating medium?
Saturday, September 29, 2012 at 9:55am

Chemistry
I have had this question in my homework, and honestly I got stuck in these questions. I managed to convert 5.3g of Na2CO3 into moles, but then I got stuck and do not know what to do next to solve the question. If anyone knows how to work this out, help from anyone is greatly ...
Saturday, September 29, 2012 at 5:04am

Chemistry
This is a question I am presently doing right now which I found in my homework. I am quite sure that in (a) I have to use the Hasselbach equation though I am not sure how to work it out. If anyone knows any of the answers, and how you got to them, please feel free to share. ...
Saturday, September 29, 2012 at 5:03am

Chemistry
This is a question I am presently doing right now which I found in my homework. I am quite sure that in (a) I have to use the Hasselbach equation though I am not sure how to work it out. If anyone knows any of the answers, and how you got to them, please feel free to share. ...
Saturday, September 29, 2012 at 5:02am

chemistry
Identify a haloalkane and describe the manner in which it functions as an anesthetic.
Saturday, September 29, 2012 at 3:36am

chemistry
A solution of ethanol (C2H50H) in water is prepared by dissolving 76.9ml of ethanol (density0.79g/cm3) in enough water to make 0.25L of solution. What is the molarity of ethanol in this solution Who helps me
Saturday, September 29, 2012 at 12:56am

chemistry
For each of the following bonds, indicate the positive end with \delta^{+} and the negative end with \delta^{-}. Write an arrow to show the dipole for each. 1. Si-Cl 2. Se-F 3. Br-F 4. N-H 5. N-P
Saturday, September 29, 2012 at 12:03am

Chemistry
How would I find the volume of 30% hydrogen peroxide solution from 20mL of 3% hydrogen peroxide solution?
Friday, September 28, 2012 at 11:26pm

College Chemistry
calculate the moles of sulfuric acid that remained in the solution after reaction with the carbonate. the tared mass of carbonate is 1.5179g
Friday, September 28, 2012 at 9:35pm

College Chemistry
calculate the average volume of sodium hydroxide required for the titration of 25.00mL of the standard sulfuric acid solution. From my data i have trial 1 and 2 to be 19.80ml and 19.80ml of NaOH used so do i just add them and divide it by two to get the average?
Friday, September 28, 2012 at 7:30pm

Chemistry
In industrial plants, what specific type of oil is used as heating medium?
Friday, September 28, 2012 at 7:27pm

chemistry
Determine the pH of a solution containing 0.045 M NaOH and 0.025 M KI: With activities: Without activities:
Friday, September 28, 2012 at 6:21pm

Wine Chemistry
Is citric acid stronger than tartaric acid?
Friday, September 28, 2012 at 3:12pm

CHEMISTRY
2C2H2+ 5O2-> 4CO2+ 2H20. If 1 mole of C2H2 reacts with oxygen, how many moles of C02 are produced.
Friday, September 28, 2012 at 2:53pm

chemistry
If the boron nitride molecule,BN, were to form, what would its structure look like? pls. need help
Friday, September 28, 2012 at 2:41pm

chemistry
is IBr a hydrogen bonding or dipole-dipole interactions or dispersion forces
Friday, September 28, 2012 at 10:50am

Chemistry Pretest
Last and final question: Consider the reaction 2KNO3 + 10K ---> 6K2O + N2. If 155 grams of K reacted with 122 grams of KNO3, what is the limiting reagent? a) KNO3 b) K c) Neither d) not enough information I would think it's d? Because it doesn't ask to know either ...
Friday, September 28, 2012 at 7:19am

Chemistry Pretest
Fe can be prepared as 2 Al + Fe2O3 ----> 2 Fe + Al2O3. Suppose that 0.450 moles of Fe2O3 are reacted with an excess of Al. Suppose that 43.6 grams of Fe are obtained. What is the percent yield of Fe? a) 16.2% b) 60.7% c) 86.7% d) 43.4% Percent yield= actual yield of product...
Friday, September 28, 2012 at 7:15am

Chemistry Pretest
Consider the following balanced equation. 2 H2 + O2 ---> 2 H2O Which of the following statements is false? a) One molecule of O2 will react with 2 molecules of H2 b) One mole of O2 will react with 2 moles of H2 c) The complete reaction of 32.0 g of O2 will produce 2 moles ...
Friday, September 28, 2012 at 7:00am

Chemistry Pretest
11. How many moles of CO2 would be produced from 56 moles of O2 according to the following balanced equation? 2 C2H6 + 7 O2 ---> 4 CO2 = 6 H20 a) 16 b) 32 c) 224 d) 48 e) 8
Friday, September 28, 2012 at 6:52am

Chemistry Pretest
1. What mass of the compound FeWO4 contains 50.0 grams of tungsten (atomic symbol W, atomic number= 74)? **Formula mass of FeWO4 is 303.69** a) 30.0 g FeWO4 b) 304 g FeWO4 c) 82.6 g FeWO4 d) 188 g FeWO4
Friday, September 28, 2012 at 6:49am

Chemistry
You are asked to prepare 500. mL of a 0.150 M acetate buffer at pH 5.00 using only pure acetic acid, 3.00 M NaOH, and water. Calculate the quantities needed for each of the following steps in the buffer preparation. 1. Add acetic acid to ~400 mL of water in a 500 mL beaker. ...
Friday, September 28, 2012 at 2:33am

chemistry
N2+ 3H2 GIVES 2NH3 = -90.5 4NH3+5O2 GIVES 4NO+6H20 =-905.1 H2 +0.5 O2 GIVES H2O =-241.1 USE THESE VALUES TO DETERMINE ENTHALPHY CHANGES
Friday, September 28, 2012 at 2:32am

Chemistry
a solution is 0.0300 m in Sodium. How many grams of sodium carbonate are necessary to prepare 900.0 ml of this solution? I don't know where to start on this.
Friday, September 28, 2012 at 1:34am

Chemistry
would adding more CaCl2 to Na2CO3 produce more chalk
Thursday, September 27, 2012 at 11:24pm

Chemistry
The Ka of a monoprotic weak acid is 3.29 × 10-3. What is the percent ionization of a 0.176 M solution of this acid?
Thursday, September 27, 2012 at 9:54pm

chemistry
In 1934, Edward A. Doisy of Washington Univeristy extracted 1361 kg og hog ovaries to isolate a few milligrams of a potent female hormone. Doisy burned 5.00 mg of this precious sample in oxygen and found that 14.54 mg of CO2 and 3.97 mg of H2O were generated. (a) determine the...
Thursday, September 27, 2012 at 9:40pm

Chemistry
calculate the volume of a rectangular prism with a length of 5.6 , a width of 2.1 , and a height of 6.6 .
Thursday, September 27, 2012 at 9:33pm

Chemistry
Suppose you are asked to find the area of a rectangle that is 2.1- wide by 5.6- long. Your calculator answer would be 11.76 . Now suppose you are asked to enter the answer to two significant figures. (Note that if you do not round your answer to two significant figures, your ...
Thursday, September 27, 2012 at 9:12pm

Chemistry
Calculate the pH of 7.2 × 10-8 M HCl. Report your answer to the hundredths place. Next, What fraction of the total H in this solution is from the HCl? Report your answer to the hundredths place. I apologize for the re-post, but I felt the previous one was labeled ...
Thursday, September 27, 2012 at 9:08pm

chemistry
How much heat is necessary to raise the temperature of a 15.0g metal from 15 degrees celsius to 25.0 degrees celsius?
Thursday, September 27, 2012 at 9:08pm

chemistry
A total of 506 J of heat are added to 50.0 g of water initially at 15.0 degrees Celsius. What is the final temperature of the water?
Thursday, September 27, 2012 at 9:04pm

chemistry
How many grams of HCL must be added to make 1 liter of a 2.0 M HCl solution?
Thursday, September 27, 2012 at 8:51pm

chemistry
How many grams of HCL must be added to make 1 liter of a 2.0 M HCl solution?
Thursday, September 27, 2012 at 8:43pm

Chemistry
How to solve titration problem for HC2H3O2 + NaOH= NaC2H3O2 + H2O The M of NaOH= 0.427 The volume of NaOH= 17.30mL 10.00mL of acid The second titration calculation is: The M of NaOH= 0.427 The volume of NaOH=34.60mL 20.00mL of acid
Thursday, September 27, 2012 at 8:16pm

chemistry
115g of copper that loses 2.48kJ
Thursday, September 27, 2012 at 7:57pm

chemistry
calculate the vapor pressureof a solution of 20.0g sucrose (C12H12O6) in 80.0g water at 25 degrees celsius (vapor pressure, P, of pure water at 25C is 24torr)
Thursday, September 27, 2012 at 6:58pm

College Chemistry
how would you prepare 175.0ml of .150 m agno3 solution starting with pure agno3
Thursday, September 27, 2012 at 6:29pm

chemistry
why do gases mix in any proportion?
Thursday, September 27, 2012 at 4:56pm

chemistry
A 27.00 mL sample of an unknown H3PO4 solution is titrated with a 0.110 M NaOH solution. The equivalence point is reached when 25.78 mL of NaOH solution is added. What is the concentration of the unknown H3PO4 solution? The neutralization reaction is: H3PO4(aq) + 3NaOH(aq) -&...
Thursday, September 27, 2012 at 4:16pm

Chemistry
A 6.00 ft cylinder has a radius of 26 in. It contains 189 lb of helium at 25 celsius. Express the volume of the cylinder (V=ðr²h) in liters, the amount of helium in moles and the temperature in Kelvin.
Thursday, September 27, 2012 at 3:48pm

Chemistry(Please answer, thanks)
I have to answer the following questions about C3H7Cl: Are there different constitutional isomers for this formula, are there different cis/trans isomer, and are there different conformers? I know that C3H7Cl can be drawn two ways: H-C-C-C-Cl With H's above and below the ...
Thursday, September 27, 2012 at 3:12pm

chemistry
how many joules of energy are required to raise 150.0g of water from 15.0 degrees to 45 degrees
Thursday, September 27, 2012 at 2:10pm

chemistry
Write the formulas of the compound Al+3 formed by specified cations with the following anions:OH-, NO3-, CO3-2,HSO4-, PO4-3 . Use the given order of anions
Thursday, September 27, 2012 at 1:31pm

chemistry
Write the formulas of the compound Pb+4 formed by specified cations with the following anions:OH-, NO3-, CO3-2,HSO4-, PO4-3 . Use the given order of anions
Thursday, September 27, 2012 at 1:30pm

chemistry
Write the formulas of the compound Al3+ formed by specified cations with the following anions:OH-, NO3-, CO3-2,HSO4-, PO4-3 . Use the given order of anions
Thursday, September 27, 2012 at 1:28pm

Chemistry
I have to answer the following questions about C3H7Cl: Are there different constitutional isomers for this formula, are there different cis/trans isomer, and are there different conformers? I know that C3H7Cl can be drawn two ways: H-C-C-C-Cl With H's above and below the 3...
Thursday, September 27, 2012 at 12:53pm

chemistry
Write the formulas of the compound NH4+ formed by specified cations with the following anions:OH-, NO3-, CO3-2,HSO4-, PO4-3 . Use the given order of anions
Thursday, September 27, 2012 at 12:47pm

Chemistry
Which element is located in the family represented by ns²np³? A) Ti B) Se C) AS D) I E) Sb
Thursday, September 27, 2012 at 12:06pm

Chemistry
Ethylene glycol has a specific gravity of 1.1088 at room temperature 25 degrees Celsius. What is the mass of 1.00L of ethylene glycol at this temperature?
Thursday, September 27, 2012 at 11:37am

Chemistry
Which statement concerning the electrons surrounding the nucleus of an atom is NOT correct? a) When 2 electrons pair together, they have opposite spins. b) The number of the electrons in an isolated neural atom is equal to the atomic number c) The second main energy level can ...
Thursday, September 27, 2012 at 11:36am

Chemistry
Calculate the density of a substance in pennyweights per peck that has a volume of 0.371 hogsheads and a mass of 41.6 kg. 1 pennyweight = 1.55 grams 1 hogshead = 238.5 liters 1 peck = 9.091 liters. Answer in units of pw/pk.
Thursday, September 27, 2012 at 11:23am

Chemistry
Suppose the atmospheric pressure during the experiment was 751 mmHg. The temperature of the water was found to be 23.0 degrees celsius. What is the pressure of the oxygen gas, Po2 that is produced?
Thursday, September 27, 2012 at 11:18am

chemistry
Record measured absorbance for each tube in following table. Complete the table by calculating the [ Fe(SCN2+)]eq and [Fe3+]initial and [HSCN]initial Data: Volume of 2.00 x 10-3 M Fe(NO3)3 solution, mL 1)5.00, 2) 5.00, 3) 5.00 4) 5.00 5) 5.00 Volume of 2.00 x 10-3 M HSCN ...
Thursday, September 27, 2012 at 11:14am

chemistry
Record measured absorbance for each tube in following table. Complete the table by calculating the [ Fe(SCN2+)]eq and [Fe3+]initial and [HSCN]initial Data: Volume of 2.00 x 10-3 M Fe(NO3)3 solution, mL 1)5.00, 2) 5.00, 3) 5.00 4) 5.00 5) 5.00 Volume of 2.00 x 10-3 M HSCN ...
Thursday, September 27, 2012 at 11:14am

chemistry
100 ml of a raw water sample on titration with 1/50N h2so4 required 12ml of the acid to phenolpthalein end-point and 15.5 ml of the acid to methyl orange end point. determine the type and extent of alkalinity present in the water sample. please explain me this problem in a ...
Thursday, September 27, 2012 at 9:31am

Chemistry
This Chem problem is really difficult -Need help please! Magnesium Consists of three naturally occuring isotopes. The percent abundance of these isotopes is as follows: 24Mg(78.70%), 25Mg(10.13%) and 26Mg(11.7%). The average atomic mass of the three isotopes is 24.3050amu. If ...
Thursday, September 27, 2012 at 6:36am

chemistry
what was the precipitate formed of pottasium bromide and lead nitrate mix with water?
Thursday, September 27, 2012 at 12:49am

organic chemistry
Why is steam distillation rather than a simple distillation used to isolate eugenol? My answer is because the temperature goes nowhere near their boiling points, which minimises the risk of decompostion. Is it that right? If not then don't you mind if you can explain to me...
Wednesday, September 26, 2012 at 11:26pm

Chemistry 011
what does Molar Mass mean?
Wednesday, September 26, 2012 at 10:11pm

Chemistry
What is the pH of a 0.50 M solution of NaNO2 if the Ka of H20x = 4.5 x 10^-4. I know that you use the Ka to find Kb and solve from there, but why?
Wednesday, September 26, 2012 at 10:04pm

Chemistry
how would you prepare 500 ml of .2M solution starting with solid NaH2PO4*H20?
Wednesday, September 26, 2012 at 9:50pm

chemistry
order Se, S, As, by increasing atomic radius? explain why?
Wednesday, September 26, 2012 at 9:44pm

chemistry
a buffer is a substance which? a) accepts OH- in basic solution b) accepts H+ in acid solutions
Wednesday, September 26, 2012 at 9:40pm

AP Chemistry
A 34.05 gram liquid sample of an unstable compound is deposited in a metal piston assembly that has a cylinder with a diameter of 20.0 cm. After the sample is added, the piston is placed in contact with the liquid and the piston vent is closed. This process removes all ...
Wednesday, September 26, 2012 at 9:39pm

chemistry
whats an example of hydrogen bonding?
Wednesday, September 26, 2012 at 9:37pm

chemistry
Use demensional analysis to convert 4.68 grams of boron to cubic centimeters of boron. The density of boron is 2.34 grams per centimeters cubed
Wednesday, September 26, 2012 at 9:13pm

Chemistry
Round this to two sig figs: 4025000 Is the correct answer 4.0 x 10^6?
Wednesday, September 26, 2012 at 8:48pm

Chemistry
Convert 3.01 x 10^23 atoms of silicon to moles of silicon. on my paper i have the equations moles S = 3.01 x 10^23 atoms x 1 mole/6.022x10^23 atoms but i'm not sure how to do this. help?
Wednesday, September 26, 2012 at 7:39pm

chemistry
how do you name halogens as a functional group. like CH3-Cl
Wednesday, September 26, 2012 at 6:31pm

Chemistry
How would I calculate the mass of 20ml of a 3% hydrogen peroxide from a 30% H2O2 solution?
Wednesday, September 26, 2012 at 5:39pm

Chemistry
I Posted this question the other day: A 1.00 g sample of enriched water, a mixture of H2O and D2O, reacted completely with Cl2 to give a mixture of HCl and DCl. The HCl and DCl were then dissolved in pure H2O to make a 1.00 L solution. A 25.00 mL sample of the 1.00 L solution ...
Wednesday, September 26, 2012 at 5:34pm

Chemistry
Lab: Titration of NaOH (0.1 molar)to unknown solid acid. Trying to determine the equilivent weight of the unknown acid in the experiement. I am trying to figure out if I add too much base solution by accident to an unknown acid during titration would it affect the equivalent ...
Wednesday, September 26, 2012 at 5:28pm

chemistry
about how many bacteria (e coli) would you have to line up to stretch 1mm??
Wednesday, September 26, 2012 at 5:27pm

chemistry
a typical E coli is 2um in length, how long is the E coli in nanometers??
Wednesday, September 26, 2012 at 5:26pm

chemistry
which temperature is colder: 50F or 50C???
Wednesday, September 26, 2012 at 5:22pm

chemistry. urgent!
where woudl i put the propyl in 2-propyl benzoate? i thought the propyl had to be attactched to the O and wouldnt that just be 1-propyl not 2?
Wednesday, September 26, 2012 at 4:44pm

general chemistry 2
How many grams of urea [CO(NH2)2] would be required to prepare 200 mL of a 5.0 x 10-3 molar solution? Answer
Wednesday, September 26, 2012 at 3:46pm

Chemistry
What is the temperature change in celsius when 29.5L of water absorbs 2.3 kwh of heat?
Wednesday, September 26, 2012 at 3:33pm

Chemistry
What volume of 0.200M of aqueous solution of formic acid, a weak monoprotic acid (KA = 1.78x10-4) and 0.200M aqueous solution of NaOH would you mix to prepare a 500mL of a buffer solution of pH = 4.0. I know I need to use the H-H equation, I'm just not sure what I plug in ...
Wednesday, September 26, 2012 at 2:31pm

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