Sunday
March 9, 2014

# Homework Help: Science: Chemistry

Chemistry
2070 BTU/hr x 24 hr/day x (365 days/yr) x 1.055 kJ/BTU x (1 megajoule/1000 kJ) = ?
Saturday, February 1, 2014 at 3:05pm

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

Chemistry
Saturday, February 1, 2014 at 2:55pm

Chemistry
N2 + 3H2 ==> 2NH3 At equilibrium, (N2) = 3.0/5.00 = ? (H2) = 2.40/5.00 = ? (NH3) = 0.565/5.00 = ? Substitute these equilibrium values into the Kc expression and evaluate Kc.
Saturday, February 1, 2014 at 2:54pm

Chemistry
192 in one s.f. is: round to 200, then 2 x 10^2 or 2E2. I obtained 196 and not 192 BUT I may be using different numbers for kcal vs grams. I used 4 kcal/g carb 4 kcal/g protein 9 kcal/g fat.
Saturday, February 1, 2014 at 2:48pm

College Chemistry
NaHCO3 + HCl ==> NaCl + H2O + CO2 mols NaHCO3 = grams/molar mass mols NaHCO3 = mols HCl (from the coefficients in the balanced equation.) mols HCl = M x L. You know M and mols, solve for L.
Saturday, February 1, 2014 at 2:42pm

Chemistry
C14H30 ==> C2H4 + H2 + C12H24 C16H34 ==> 2C2H4 + C3H6 + C9H20
Saturday, February 1, 2014 at 2:39pm

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
23.804
Saturday, February 1, 2014 at 1:06pm

Chemistry
Nevermind, I think the answer is 192, but how do I express this in one sig fig?
Saturday, February 1, 2014 at 12:16pm

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
1. Write and balance the equation. 2. Use density gasoline to convert 9.0 gallons to grams. 3. Look up the heat of combustion or calculate it from the delta H formation values. 4. heat combustion x (grams gasoline/molar mass gasoline). Post your work or supply details (numbers...
Saturday, February 1, 2014 at 12:08pm

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

COURSE HELP PLEASE ms sue qq
In high school, these courses are usually called Algebra I Algebra II Geometry Pre-calculus AP Calculus Biology AP Biology Chemistry AP Chemistry Physics AP Physics Work with your counselor to make sure you take the required courses for graduation AND as many of these as ...
Saturday, February 1, 2014 at 9:41am

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
kc= [x)(x)/(2*.76-x)= 1.8 x^2=1.8(1.52-x) solve that quadratic for x x^2+1.8x-2.74=0 x= (-1.8+-sqrt(3.24+10.96) )/2 x= -.9+- 3.77/2= ..985 moles/liter or conce of Pcl5 is 2*.76-.985 check my math.
Friday, January 31, 2014 at 10:25pm

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
hydrogen nucleus = 1 gram/mol = 1 amu * AV molecules/mol * 1.6605*10^-24 grams/amu so AV = 1 /(1.6605*10^-24 = .6022 * 10^24 = 6.022*10^23
Friday, January 31, 2014 at 6:15pm

chemistry
mLHCl x MHCl = mLNaOH x MNaOH Substitute and solve for MHCl and compare with 0.400. Of course you need not do a calculation. If the NaOH is 0.400 and it takes more HCl to neutralize the NaOH you know HCl is weaker than NaOH or HCl < 0.400M
Friday, January 31, 2014 at 6:11pm

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 (?)
Indicate your specific subject in the "School Subject" box, so those with expertise in the area will respond to the question. What is your question?
Friday, January 31, 2014 at 11:44am

Chemistry
I worked this last night. If you have questions about that show your work and explain what you don't understand.
Friday, January 31, 2014 at 11:03am

Chemistry
-91.8 kJ x (500/28) = -?
Friday, January 31, 2014 at 11:02am

Chemistry
Friday, January 31, 2014 at 11:01am

Chemistry
12*(x) + 13(1-x) = 12.35 Solve for x
Friday, January 31, 2014 at 11:00am

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 Q1,3,5
what is wrong with running a reaction with the tert-butyl alcohol that is cooled to 0 degree Celsius in an ice bath?
Friday, January 31, 2014 at 6:39am

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 WHAT? are in 7.40 cc? By the way, cc is a much simpler way to write that than 7.40 \{rm cm}^{3}\
Thursday, January 30, 2014 at 9:42pm

Chemistry
q is computed in steps. Within a phase q = mass x specific heat x (Tfinal-Tinitial). For example, to heat 20 g H2O from zero to 100 C (within the liquid phase) it requires q = 20g x 4.184 J/g*C x (100C-0C) = ? At a phase change (solid to liquid or liquid to vapor) it is q = ...
Thursday, January 30, 2014 at 9:38pm

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
IS this right?
Thursday, January 30, 2014 at 8:57pm

Chemistry
s
Thursday, January 30, 2014 at 8:20pm

chemistry
see other post.
Thursday, January 30, 2014 at 7:52pm

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
massolivoil=densityoil*volume massgasoline=densitygas*2L set the equal, and solve for volume
Thursday, January 30, 2014 at 7:51pm

chemistry
What volume is 2.00 LL? Is that 2.00 liters? mass 2.00L gasoline = volume x density = 2.00 L x density gasoline (you must look up the density gasoline). Then volume olive oil = mass/density = mass gasoline from above/density olive oil. Solve for volume olive oil.
Thursday, January 30, 2014 at 7:50pm

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
Do this like the NaCl M problem. Post your work if you get stuck.
Thursday, January 30, 2014 at 7:04pm

AP Chemistry
HCl + NaOH ==> NaCl + H2O mols HCl = M x L = 3.2 x 0.4 = 1.28 mols NaOH = M x L = 2 x 0.3 = 0.6 mols NaCl formed = 0.6 M NaCl = mols/L = 0.6/(0.4+0.3) = ?
Thursday, January 30, 2014 at 7:04pm

Chemistry
5,17
Thursday, January 30, 2014 at 7:02pm

AP Chemistry
You should be able to do this with the NaOH vs HCl problem. Post your work if you get stuck.
Thursday, January 30, 2014 at 6:58pm

AP Chemistry
Salts are made up of a. a cation other than H ion. b. an anion other than hydroxide.
Thursday, January 30, 2014 at 6:57pm

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
pH = -log (H^+). Substitute and solve for M HCl Then follow the instructions above for HCl vs NaOH problem.
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
All of this type can be worked the same way. 1. Write and balance the equation. NaOH + HCl ==> NaCl + H2O 2. How many mols do you have? mols = M x L = 0.81M x 0.77L = 0.624 3. Since 1 mol NaOH = 1 mol HCl (from the equation), then mols HCl = mols NaOH. 4. Those three steps ...
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
Could you re-type the question as it is written in your booklet or your worksheet?
Thursday, January 30, 2014 at 4:54pm

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
Use (P1V1/T1) = (P2V2/T2) The easy way to do this is to make up a convenient number for P1 and V1 and multiply by 4 to find P2 and V2. Another way is to call P1 = P1, then P2 = 4P1. While V1 = V1 and V2 = 4V1
Thursday, January 30, 2014 at 3:45pm

chemistry
Thursday, January 30, 2014 at 3:42pm

college chemistry
melt ice + move ice from zero to final T + cool H2O from 8 to final T = 0 (mass ice x heat fusion) + (mass melted ice x specific heat H2O x (Tfinal-Tinitial) + (mass H2O x speicif heat H2O x (Tfinal-Tinitial) = 0 Solve for mass H2O. I obtained 420 g but you should confirm that...
Thursday, January 30, 2014 at 3:41pm

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
This question isn't worded very well in my opinion but I think you want just the enthalpy for the reaction given. Those are dHrxn = (n*dH products) - (n*dH reactants) dHrxn = (1*MgCl2 + 1*H2O) - (1*MgO + 2*HCl) dHrxn = [1*(-641) + 1*(-286)] - [1*(-602) + 2*(-167)] = ?
Thursday, January 30, 2014 at 3:24pm

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
E = hc/wavelength = 6.626E-34*3E8/510E-9 = about 4E-19 J/photon but you need to do it more accurately. 1000 J/s*m^2 x 1.3 c (1 m/100 cm) x (1 m/100 cm) = ?P = power of sun hitting a 1.3 cm^2 area. Then 4E-19 J/photon x #photons = ?P Solve for # photons.
Thursday, January 30, 2014 at 3:12pm

chemistry
It looks balanced to me.
Thursday, January 30, 2014 at 2:38pm

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

chemistry
Three steps are involved: steam changing to water at 100 C; water at 100 C cooling to 0 C; water at 0 C freezing to ice at 0 C. Steam changing to water: Heat of vaporization of water is 539.4 cal/g Heat = Heat of Vap. x mass = 539.4 cal/g x 75.0 g = 40,500 cal Cooling water ...
Thursday, January 30, 2014 at 12:28pm

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 12:25pm

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
J = 275 x heat fusion = ?
Thursday, January 30, 2014 at 12:07am

Chemistry
2070 BTU/hr x 24 hr/day x 365 d/yr = ?BTU ?BTU x 1.055 kJ/BTU = ? kJ. ? kJ x (1 MJ/1000 kJ) = ? MJ.
Wednesday, January 29, 2014 at 10:58pm

Chemistry
79.0 kilobytes = 0.07715 megabytes. 0.07715 mB/s x #s = 13.3 megabytes. Solve for #s and convert to minutes.
Wednesday, January 29, 2014 at 10:54pm

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
I found the first 2 steps, but don't know what to do next. how do i find the volume to plug it into the equation: PV=nRT?
Wednesday, January 29, 2014 at 10:09pm

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
r=329pm=329E-12 m r^3= (3.29E-10)^3=35.6E-30m^3 Put that in the formula, and compute V
Wednesday, January 29, 2014 at 9:47pm

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

incomplete---Chemistry
no data listed.
Wednesday, January 29, 2014 at 9:03pm

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
density x 1000 mL x %H3PO4 x (1/molar mass) = 15M Solve for density = approximately 1.7 but you need to do it more accurately. mass of 1000 mL = 1.73 x 1000 mL = 1730 g mass H3PO4 = 1730 x 0.85 = 1470g g solvent = 1730g-1470 = 260g m = mols solute/kg solvent/kg solvent = 15/0....
Wednesday, January 29, 2014 at 8:26pm

general chemistry II
Assume 1000 grams of solution. then you have 850 grams phosphoric acid, and 150 grams of water. 15M=850/molmassH3PO4 / volumeinL solve for volume, = 850/(molmass*15), figure molmass, then calculate volume. finally, density= masssoluton/volumeL= = 1000g/volumeL figured above ...
Wednesday, January 29, 2014 at 8:12pm

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
Hmmmm. that is far from right. Heatgained= mass*specificheat*change in temp change in temp= heatgaind/(specificheat*mass) change in temp= 125cal/(.0920cal/gC * 60g) = 33.6 check that chaknge in temp= finaltemp-initial temp so final temp= 33.6+20 C
Wednesday, January 29, 2014 at 7:40pm

chemistry
So what I'm getting as I set up the equation is 60g x 125 x 60 and that doesn't seem right
Wednesday, January 29, 2014 at 7:35pm

Chemistry
Gcvb
Wednesday, January 29, 2014 at 7:34pm

Pages: <<Prev | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | Next>>

Search
Members