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October 31, 2014

Homework Help: Science: Chemistry

Recent Homework Questions About Chemistry

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Chemistry
What mass in grams of a 0.500 m(molal) solution of sodium acetate, CH3CO2Na, in water would you use to obtain 0.200mol of sodium acetate?
Sunday, February 2, 2014 at 3:59am

Chemistry
At 1 atm, how much energy is required to heat 35.0 g of H2O(s) at –12.0 °C to H2O(g) at 127.0 °C?
Sunday, February 2, 2014 at 3:08am

CHemistry
At 1 atm, how much energy is required to heat 35.0 g of H2O(s) at –12.0 °C to H2O(g) at 127.0 °C?
Sunday, February 2, 2014 at 3:07am

chemistry
The laboratory tech accidentally mixed NaHCO3 with BaCl2-2H2O instead of KCl when preparing unknown mixture for this experiment. How would this mistake affect the calculated percentage of NaHCO3 in the mixture? Justify answer with an explanation. Is it still possible to ...
Sunday, February 2, 2014 at 1:08am

chemistry
A student dried a wet crucible with a Kimwipe. A piece of Kimwipe was left clinging to the inside wall of the crucible, The student did not see the piece of Kimwipe when adding the NaHCO3-KCl mixture to the crucible. The crucible ans its contents were weighed and subjected to ...
Sunday, February 2, 2014 at 1:05am

Chemistry
A student cleaned a crucible with HCl. After pouring the HCl into the waste container, the crucible was neither rinsed with water or dried before the student added the NaHCO3 and KCl mixture. The crucible contained some residual HCl. How would this experimental error affect ...
Sunday, February 2, 2014 at 12:29am

chemistry
so we did a chem lab and one of the questions is to tabulate the amount of S2O3 consumed in moles and times (sec) for each run. I'm just not sure how to calculate the amount consumed. Can someone please explain how?
Saturday, February 1, 2014 at 10:40pm

CHEMISTRY
The grams of protein in 1 cup of soup that has 110 Cal{\rm Cal} with 7 g{\rm g} of fat and 9 g{\rm g} of carbohydrate. Express your answer using one significant figure.
Saturday, February 1, 2014 at 8:53pm

chemistry
Calculate the pH of .100 of a buffer solution that is .25 M in HF and .50 M in NaF. What is the change in pH on addition of the following? A. .002 mol of HNO3 B. >004 mol of KOH I calculated the correct pH of the solution but am having trouble calculating A & B. Thanks, Ivy
Saturday, February 1, 2014 at 7:11pm

Chemistry
What volume of oxygen at 25 degrees celsius and 93.5 kPa will use up 57.1 g of butane?
Saturday, February 1, 2014 at 6:15pm

chemistry
Just need help solving this one, please: The grams of fat in one avocado if it has 405 Calories, 13 g of carbohydrate, and 5 g of protein Express your answer using one significant figure. Thanks -MC
Saturday, February 1, 2014 at 4:47pm

chemistry
I need help solving this: The grams of protein in 1 cup of soup that has 110 Cal with 7 g of fat and 9 g of carbohydrate. Express your answer using one significant figure. Thanks -MC
Saturday, February 1, 2014 at 4:29pm

Chemistry
What is the maximum height achieved if a 0.800 kg mass is thrown straight upward with an initial speed of 40.0 m·s–1? Ignore the effect of air resistance.
Saturday, February 1, 2014 at 3:50pm

Chemistry
The FDA recommends that women who are pregnant avoid eating more than three 6.00-oz servings of bluefish per month because of the relatively high mercury levels in that type of fish. If bluefish contains 0.341 ppm of mercury (that is, 0.341 oz of mercury per 1×106 oz of ...
Saturday, February 1, 2014 at 3:37pm

Chemistry
An office heater puts out 2070 Btus (British thermal units) of energy in the form of heat per hour. Given that 1 Btu = 1.055 kJ, how many megajoules of energy in the form of heat can be produced per year (365 days) by the heater (assume continuous operation)?
Saturday, February 1, 2014 at 2:59pm

College Chemistry
In your experiment you weigh out 0.995 g NaHCO3. How much 1.0 M HCl should you add to get the most NaCl?
Saturday, February 1, 2014 at 1:38pm

Chemistry
Write a balanced equation to describe the following reactions: a) C14H30 is cracked to produce ethene, hydrogen and one other compound b) C16H34 is cracked to produce ethene and propene in a 2:1 ratio and only one other compound Thanks:)
Saturday, February 1, 2014 at 1:07pm

Chemistry
The total Calories for 2 tablespoons of crunchy peanut butter that contains 6 g of carbohydrate, 16 g of fat, and 7 g of protein. Express your answer using one significant figure. How do I figure out the amount of kcal per carb fat and protein? Thanks -MC
Saturday, February 1, 2014 at 12:13pm

college chemistry
How many megajoules are released when 9.0 gal of gasoline burns. how do I start to do this problem, and what are the steps to get there. thank you
Saturday, February 1, 2014 at 11:51am

Chemistry
Some N2 and H2 are placed in an empty 5.00 liter container at 500 degree celcius. When equilibrium is established, 3.0mol N2, 2.40mol H2 and 0.565mol of NH3 are present. Evaluate Kc for the reaction at 500 degree celcius.
Saturday, February 1, 2014 at 4:06am

Chemistry
Some N2 and H2 are placed in an empty 5.00 liter container at 500 degree celcius. When equilibrium is established, 3.0mol N2, 2.40mol H2 and 0.565mol of NH3 are present. Evaluate Kc for the reaction at 500 degree celcius.
Saturday, February 1, 2014 at 4:05am

ap chemistry
a 0.76 mol sample of pcl5 is placed in a 500 ml reaction vessel. what is the concentration of pcl5 when the reaction pcl5(g) ⇀↽ pcl3(g) + cl2(g) has reached equilibrium at 250◦c (when kc = 1.8)
Friday, January 31, 2014 at 8:54pm

chemistry
The molar mass of HCl is 36.5g use the fact that 1 amu = 1.6605x 10-24g power g to calculate Avogradro’s number.
Friday, January 31, 2014 at 4:10pm

Chemistry
Henry constant for the dissolving of nitrogen in water was reported as 7e-4 mol/Latm at 20 deg Celsius. What is the value of the equilibrium constant, K, at 20 deg Celsius for the process N2(g0)=N2(aq). If the amount of nitrogen in aqueous solution is .1 mol N2 and the partial...
Friday, January 31, 2014 at 1:57pm

chemistry
A chemist needs a HCl solution with a molarity of less than 0.400 M for an experiment. To find out if a sample of HCl solution can be used in the lab, the chemist performs a titration to neutralize 59.2 mL of the HCl with 45 mL of 0.400 M NaOH. Based on the results, will the ...
Friday, January 31, 2014 at 12:02pm

Chemistry
How much heat is evolved when 500kg of Ammonia is evolved according to the following equation: N2(g)+3H2(g)<->2NH3(g) [deltaH =-91.8K]
Friday, January 31, 2014 at 10:25am

Chemistry
If an element N has isotopic abundances X% of mass number 12, atomic number 6, and Y% of N of mass number 13, atomic number 6. If their relative isotopic mass is 12.35. Find X and Y.
Friday, January 31, 2014 at 10:01am

Chemistry
If an element N has isotopic abundances X% of mass number 12, atomic number 6, and Y% of N of mass number 13, atomic number 6. If their relative isotopic mass is 12.35. Find X and Y.
Friday, January 31, 2014 at 10:01am

Chemistry
Consider the process where 1.3 moles of ice, initially at -30.0 C, is heated to 140.0 C at constant pressure of 1.00 atm. The molar heat capacities (Cp) for solid, liquid, and gaseous water (37.5 J K-1 mol-1, 75.3 J K-1 mol-1, 36.4 J K-1 mol-1, respectively) are assumed to be ...
Friday, January 31, 2014 at 3:04am

chemistry heelp
What volume of a solution that is 15.7 % (w/w) lolinic acid (density = 1.64 g/mL) contains 4.25 g of lolinic acid15. What is the molarity of a 20.2 % (w/w) solution of rossonic acid (423.6 g mol-1) that has a density of 1.78 g mL-1?
Friday, January 31, 2014 at 2:32am

Chemistry help pls helppppp
What volume of a solution that is 15.7 % (w/w) lolinic acid (density = 1.64 g/mL) contains 4.25 g of lolinic acid? What is the molarity of a 20.2 % (w/w) solution of rossonic acid (423.6 g mol-1) that has a density of 1.78 g mL-1?
Friday, January 31, 2014 at 1:37am

Chemistry
A particular brand of gasoline has a density of 0.737 g/mL at 25 ∘C. How many grams of this gasoline would fill a 15.1gal tank?
Thursday, January 30, 2014 at 11:56pm

Chemistry
While in Europe, if you drive 109km per day, how much money would you spend on gas in one week if gas costs 1.10 euros per liter and your car's gas mileage is 23.0mi/gal ? Assume that 1euro=1.26dollars.
Thursday, January 30, 2014 at 11:48pm

chemistry
How many \({\rm m}^{3}\) are in 7.40 \({rm cm}^{3}\)?
Thursday, January 30, 2014 at 9:34pm

Chemistry
Consider the process where 1.3 moles of ice, initially at -30.0 C, is heated to 140.0 C at constant pressure of 1.00 atm. The molar heat capacities (Cp) for solid, liquid, and gaseous water (37.5 J K-1 mol-1, 75.3 J K-1 mol-1, 36.4 J K-1 mol-1, respectively) are assumed to be ...
Thursday, January 30, 2014 at 9:17pm

chemistry
How many cubic centimeters (cm3{\rm cm}^3) of olive oil have the same mass as 2.00LL of gasoline?
Thursday, January 30, 2014 at 7:51pm

chemistry
How many cubic centimeters (cm3{\rm cm}^3) of olive oil have the same mass as 2.00LL of gasoline?
Thursday, January 30, 2014 at 7:43pm

AP Chemistry
If 435 mL of 2.7 molar HCl solution is added to 128 mL of 3.2 molar Ba(OH)2 solution, what will be the molarity of BaCl2 in the resulting solution? Answer in units of M
Thursday, January 30, 2014 at 6:53pm

AP Chemistry
If 400 mL of 3.2 molar HCl solution is added to 300 mL of 2 molar NaOH solution, what will be the molarity of NaCl in the resulting solution? Answer in units of M
Thursday, January 30, 2014 at 6:51pm

AP Chemistry
A 65 mL sample of a solution of sulfuric acid is neutralized by 46 mL of a 0.14 M sodium hydroxide solution. Calculate the molarity of the sulfuric acid solution. Answer in units of mol/L
Thursday, January 30, 2014 at 6:47pm

AP Chemistry
How many moles of NaOH will it take to neutralize 0.77 L of 0.81 M HCl? Answer in units of mol
Thursday, January 30, 2014 at 6:46pm

AP Chemistry
50.0 mL of an HCl solution with a pH of 3.5 neutralizes 200.0 mL of a Ca(OH)2 solution. What is the molarity of the Ca(OH)2 solution?
Thursday, January 30, 2014 at 6:42pm

AP Chemistry
Which one of the following compounds is not a salt? 1. Ca(ClO4)2 2. Fe(NO3)3 3. Cr(OH)3 4. Na2SO3 5. KMnO4
Thursday, January 30, 2014 at 6:37pm

help me with this language arts.
Multiple Choice 1. A court order that integrated the schools in a city would (1 point) bring students of different races together. close down the schools. keep students of different races apart. 2. Read the following passage from Through My Eyes: After the first day, I was ...
Thursday, January 30, 2014 at 6:22pm

college chemistry
DrBob222. when you move ice from zero to final T. Do you add 100 cal.?
Thursday, January 30, 2014 at 5:31pm

chemistry
How to do this equation!? Ok if you have 0.125g of copper at 23ºC. How much energy is needed to convert this copper to a temperature of 455ºC?
Thursday, January 30, 2014 at 4:45pm

chemistry
A certain volume of a gas at 298kelvin is heated such that its volume and pressure are now four times their original value.What is the new tewperature?
Thursday, January 30, 2014 at 3:37pm

college chemistry
a 42 piece of ice at 0.0 C is added to a sample of water at 8.0 C. all of the ice melts and the temperature of the water decreases to 0.0 C. how many grams of water were in the sample.
Thursday, January 30, 2014 at 3:26pm

chemistry
a 42 piece of ice at 0.0 C is added to a sample of water at 8.0 C. all of the ice melts and the temperature of the water decreases to 0.0 C. how many grams of water were in the sample.
Thursday, January 30, 2014 at 3:18pm

chemistry
Need help balancing this chemical reaction equation Ca(NO3)2+2NaOH>Ca(OH)2+2NaNO3
Thursday, January 30, 2014 at 2:06pm

chemistry
how many kilocalories of heat are released when 85g steam at 100 degrees C converted to ice at 0.
Thursday, January 30, 2014 at 12:22pm

Chemistry
What is the mass of sodium nitrate NaNO3 that you would need to add to 250 g of water in order to prepare a solution that is 0.200 molal in NaNO3?
Thursday, January 30, 2014 at 12:19pm

Chemistry
At noon on a clear day, sunlight reaches the earth\'s surface at Madison, Wisconsin, with an average power of approximately 1.00 kJ·s–1·m–2. If the sunlight consists of photons with an average wavelength of 510.0 nm, how many photons strike a 1.30 ...
Thursday, January 30, 2014 at 10:40am

Chemistry
Calculate the enthalpy change of formation for the following reactions using Hess's law, and the enthalpies of formation given in Figure 4: b) MgO +2HCl --> MgCl2 +H2O c)NaOH+ HCl -->NaCl +H20 Figure4: the given enthalpies of formation compound values are: Mg(OH)2 is...
Thursday, January 30, 2014 at 7:40am

Chemistry
A particular MP3 encoder can convert 79.0 kilobytes (kb) of music per second from a typical music CD. How many minutes will it take to convert 13.3 megabytes (Mb) of music from a CD?
Wednesday, January 29, 2014 at 10:13pm

Chemistry
An office heater puts out 2070 Btus (British thermal units) of energy in the form of heat per hour. Given that 1 Btu = 1.055 kJ, how many megajoules of energy in the form of heat can be produced per year (365 days) by the heater (assume continuous operation)?
Wednesday, January 29, 2014 at 10:02pm

chemistry
A solution is prepared by dissolving 10.00 grams of a monobasic salt in a total volume of 1.00 litres. The pH of this solution was measured at 13.07 and a conductivity experiment determined that this salt was completely ionized in solution. What is the molecular weight of this...
Wednesday, January 29, 2014 at 9:36pm

Chemistry
The volume of a sphere is given by V=(4/3)3.14r^3, where r is the radius. Compute the volume of a sphere with a radius of 329pm. state your answer in units of m^3.
Wednesday, January 29, 2014 at 9:33pm

chemistry
calculate the heat needed at 0c each of the following joules to freeze 275gof water
Wednesday, January 29, 2014 at 9:22pm

Chemistry
From data below, calculate the total heat (in J) associated with the conversion of 0.265 mol ethanol gas (C2H6O) at 451°C and 1 atm to liquid ethanol at 25.0°C and 1 atm. (Pay attention to the sign of the heat.)
Wednesday, January 29, 2014 at 8:54pm

general chemistry II
Phosphoric Acid is usually obtained at an 85% phosphoric acid solution, by mass. If this solution is 15 M, what is the density of the solution? What is its MOLALITY?
Wednesday, January 29, 2014 at 7:45pm

chemistry
I'm not sure how to solve this: If 125 cal of heat is applied to a 60.0-g piece of copper at 20.0∘C , what will the final temperature be? The specific heat of copper is 0.0920 cal/(g⋅∘C). Express the final temperature numerically in degrees Celsius Thanks
Wednesday, January 29, 2014 at 7:20pm

Chemistry
I have this problem: How much heat energy is required to raise the temperature of 0.365kg of copper from 23.0 ∘C to 60.0 ∘C? The specific heat of copper is 0.0920 cal/(g⋅∘C). I did the equation using formula Heat= mass x change in temperature x specific...
Wednesday, January 29, 2014 at 1:03pm

chemistry
Ammonium chloride and sodium nitrite react to form sodium chloride, water and nitrogen gas. If 6.33 moles of ammonium chloride react with sodium nitrite, how many grams of sodium chloride will be produced?
Wednesday, January 29, 2014 at 11:18am

chemistry
osmotic pressure of a solution containing 7g of protein in 100ml of solution is 20mmhg at37celsius calculate molecular mass of the protein
Wednesday, January 29, 2014 at 10:08am

chemistry
If someone swallows ammonia, what would they drink to counteract it? Water, Milk, Orange Juice, Tea
Wednesday, January 29, 2014 at 8:45am

chemistry
calculate the number of calcium ions present in 11.1 grammes ofcalcuimchloride(1mole=6.02*10^23)
Wednesday, January 29, 2014 at 3:57am

chemistry
calculate the number of calcium ions present in calcuimchloride
Wednesday, January 29, 2014 at 3:50am

Chemistry
The pH of a solution prepared by mixing 325 mL of 0.25 M NaOH and 675 mL of 0.20 M HClO3 is 6.50. Solve for Ka.
Wednesday, January 29, 2014 at 2:49am

Chemistry
(a)What is the pH of a solution made by combining 200 mL of 0.1 M Lactic Acid with 300 mL of 0.075 M sodium lactate? (b) If 20 mL of 0.4 M HCl is added to the solution from (a) what is the resulting pH?
Tuesday, January 28, 2014 at 10:12pm

Chemistry
Where can I find some chemical equations about land pollution? Please give me the website link.
Tuesday, January 28, 2014 at 9:18pm

chemistry
State how you would prepare each solution: 1) 455g of a solution of C3H5(OH)3 in water in which the mole fraction of glycine is .250 2) 755g of 1.4 molality solution of napathalene C10H8 in benzene C6H6. My instructor told us to find the amount of grams in order to get the ...
Tuesday, January 28, 2014 at 8:35pm

Chemistry
Colligative Properties The freezing point of distilled water was determined by recording a thermogram: -0.176 degrees Celsius. The freezing point of a 0.200 m (molality) solution containing an unknown, ionic compound was determined by recording a second thermogram: -.904 ...
Tuesday, January 28, 2014 at 5:59pm

chemistry
calculate the percentages by mass of the component element in sodium trioxonitrate(v)
Tuesday, January 28, 2014 at 2:57pm

Chemistry
Can you list some chemical equations about water pollution? At least 5.
Tuesday, January 28, 2014 at 1:21pm

chemistry
equation for joules needed to increase water temp
Tuesday, January 28, 2014 at 12:14pm

Chemistry
What is the reaction between methanol and ethanoic acid when heated?
Tuesday, January 28, 2014 at 10:58am

Chemistry Combined Gas Law
Hi so im reviewing or our long test tomorrow on combined gas law and gay lussac's well here, combined gas law i find it (maybe ) confusing to do this one, because theres no right answers because it is a practice exercise.. what i know on combined gas law is that pressure ...
Tuesday, January 28, 2014 at 9:47am

chemistry
By using the method of neutralization the acidity of the bee sting can be neutralized. What is the underlying principle and what are the chemical equations involved.
Tuesday, January 28, 2014 at 2:25am

Chemistry
Colligative Properties The freezing point of distilled water was determined by recording a thermogram: -0.176. The freezing point of a 0.200 m (molality) solution containing an unknown, ionic compound was determined by recording a second thermogram. a. Determine the freezing ...
Tuesday, January 28, 2014 at 12:56am

Chemistry
A 1.00% by mass MgSO4 solution has a freezing point of -.192°C. Water has a Kf of 1.86 (KxKg)/mol. a.) Estimate the van’t Hoff i factor from the data. b.)Determine the total molality of all solute species. c.) Calculate the percentage dissociation of MgSO4 in this ...
Monday, January 27, 2014 at 10:24pm

chemistry
A sample of nitrogen gas is confined in a 8.278 x 10-2 L container at 2.236 x 102 torr and 50 oC. How many moles of gas are present in the sample?
Monday, January 27, 2014 at 9:21pm

Chemistry
Trichloroethane, C2H3Cl3, is the active ingredient in aerosols that claim to stain-proof men's ties. Trichloroethane has a vapor pressure of 100.0 mm Hg at 20.0 C and boils at 74.1 C. An uncovered cup (1/2 pint) of trichloroethane (d=1.325 g/mL) is kept in an 18-ft3 ...
Monday, January 27, 2014 at 9:13pm

CHEMISTRY URGENT!!!!
An electron transition in a single H-atom from n=3 to n=2 results in the release of a single photon. What is the wavelength of this photon in nanometers? NEED ANSWER CUZ MINE ISNT WORKING
Monday, January 27, 2014 at 8:27pm

chemistry
if a coin with 3.0 cm diameter, 0.2 cm thickness weighs 10.377g, what are its volume and density?
Monday, January 27, 2014 at 8:25pm

Chemistry
I need help with naming two complex ions 1) [Fe(H2O)4C2O4]+ 2)[Fe(C2O4)3]3-
Monday, January 27, 2014 at 7:09pm

Chemistry
An electron transition in a single H-atom from n=3 to n=2 results in the release of a single photon. What is the wavelength of this photon in nanometers? How do I solve this?
Monday, January 27, 2014 at 7:06pm

Chemistry
1.A patient needs 2.10×10−2g of a sulfa drug. There are 8.00mg tablets in stock. How many tablets should be given? Really need help with this! :/ Thanks -MC
Monday, January 27, 2014 at 5:54pm

Chemistry
Given the reactant side of the total ionic equation for the neutralization reaction of ammonium hydroxide (NH4OH) with hydrochloric acid (HCl), write the total ionic equation (also known as the complete ionic equation) by entering both the reactant and the product species, ...
Monday, January 27, 2014 at 4:09pm

chemistry
why is it that protonated pyrone have a higher pKa than protonated acetone?
Monday, January 27, 2014 at 9:52am

chemistry
what is the freezing point depression of water, benzene, acetic acid, ethanol and clyclohexane?
Monday, January 27, 2014 at 7:19am

organic chemistry
why is it that protonated pyrone have a higher pKa than protonated acetone?
Monday, January 27, 2014 at 12:49am

Chemistry
Assume that the complete combustion of one mole of ethanol to carbon dioxide and water liberates 1370 kJ/mol (?G°\' = –1370 kJ/mol). If the energy generated by the combustion of ethanol is entirely converted to the synthesis of a hypothetical compound X, calculate...
Monday, January 27, 2014 at 12:46am

Chemistry
Water is composed of 11.2% hydrogen and 88.8% oxygen. what mass of water contains 50.0g of 0xygen?
Monday, January 27, 2014 at 12:13am

Chemistry
How much heat energy, in kilojoules, is required to convert 63.0g of ice at −18.0 ∘C to water at 25.0 ∘C ?
Sunday, January 26, 2014 at 11:23pm

chemistry
1. An 887.0 mg sample of a mixture containing only NaCl and KCl is dissolved in water, and excess AgNO3 is added to yield 1.913 g of AgCl. Compute the mass-% of each compound in the mixture.
Sunday, January 26, 2014 at 11:21pm

chemistry
which weighs more a 101cm ^3 of copper or 92.0cm^3 of iron show work
Sunday, January 26, 2014 at 10:47pm

Chemistry
A 1.250 g mass of standard aspirin is dissolved in approximately 20 mL of 1 M NaOH. This solution is added to a 250-mL volumetric flask and diluted to the mark with DI water. How many grams per mL of aspirin are in the resulting solution? (Note that a 250-mL volumetric flask ...
Sunday, January 26, 2014 at 8:39pm

chemistry
An unknown substance has a mass of 28.1 g. The temperature of the substance increases by 16.3 degrees Celsius when 176 J of heat is added to the substance. What is the most likely identity of the substance? The table lists the specific heat capacities of select substances.
Sunday, January 26, 2014 at 7:56pm

Chemistry - Posted for Rudy
Posted by Rudy on Sunday, January 26, 2014 at 7:24pm. 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 ...
Sunday, January 26, 2014 at 7:32pm

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