Tuesday
September 2, 2014

Posts by Lauren


Total # Posts: 1,502

Chemistry
yes I know how big that is but I figured that you had 2 atoms of 6.02 x 10^23 so I divided by 2 to get the mass of 1 mol which is 3.01 X 10^23... why wouldnt you just take the 100 pm and make it into kg.
November 3, 2007

Chemistry
3.01 x 10^23 ???
November 3, 2007

Chemistry
sorry I copied the wrong problem it is supposed to be: 521 m/s not 6210 m/s 6.63 X 10^-34/ (? kg)(521 m/s) How do I get the kg for this problem
November 3, 2007

Chemistry
What is the de Broglie wavelength of an oxygen molecule, O2 traveling at 521 m/s? Is the wavelength much smaller or much larger than the diameter of an atom. (on the order of 100 pm) De Broglie wavelength = h/mv h = Planck's constant in J*s. m is mass in kg. v is velocity ...
November 3, 2007

Chemistry
The space probe Pioneer 11 was launched April 5,1973, and reached Jupiter in December 1974 traveling a distance of 998 million km. How long did it take an electromagnectic signal to travel to earth from Pioneer 11 when it was near Jupiter. Where do I begin???
November 1, 2007

Chemistry
What is the de Broglie wavelength of an oxygen molecule, O2 traveling at 521 m/s? Is the wavelength much smaller or much larger than the diameter of an atom. (on the order of 100 pm) How do I do this
November 1, 2007

Chemistry
What is the wavelength of a proton traveling at a speed of 6.21 km/s? What would be the region of the spectrum for electromagnetic radiation of this wavelength. How do I do this
November 1, 2007

Chem
How much heat is released when a mixture containing 10.0g CS2 and 10.0 g Cl2 reacts by the equation. CS2 + 3Cl2 ----> S2Cl2 + CCl4 Delta H = -230 kJ
November 1, 2007

Chemistry
A sample of natural gas is 80.0% CH4 and 20.0% C2H6 by mass. What is the heat from the combustion of 1.00 g of this mixture? Assume the products are CO2 and H2O. CH4 = -74.87 and C2H6 = -84.68
November 1, 2007

Chem
is 3.00 x 10^8 m/s the speed of light
November 1, 2007

Chem
distance is 998 million km what is veloctyoflight
November 1, 2007

Chem
The space probe Pioneer 11 was launched April 5,1973, and reached Jupiter in December 1974 traveling a distance of 998 million km. How long did it take an electromagnectic signal to travel to earth from Pioneer 11 when it was near Jupiter.
November 1, 2007

Chem
frequency = speed of light/656 nm how do you find the speed of light
November 1, 2007

Chem
Calculate the frequency associated with light of wavelength 656nm. (this corresponds to one of the wavelengths of light emitted by the hydrogen atom.)
November 1, 2007

Chem
Microwaves have frequencies in the range 10^9to 10^12/s (cycles per second) equivalent to between 1 gigahertz and 1 terahertz. What is the wave length of microwave radiation whose frequency is 1.258 X 10^10/s? How do I solve this problem
November 1, 2007

Chemistry
what do you mean by proportions???
November 1, 2007

Chemistry
How much heat is released when a mixture containing 10.0g CS2 and 10.0 g Cl2 reacts by the equation. CS2 + 3Cl2 ----> S2Cl2 + CCl4 Delta H = -230 kJ
November 1, 2007

Chemistry
so CH4 = -74.87 and C2H6 = -84.68 what do you mean by take 80% and 20%???
November 1, 2007

Chemistry
A sample of natural gas is 80.0% CH4 and 20.0% C2H6 by mass. What is the heat from the combustion of 1.00 g of this mixture? Assume the products are CO2 and H2O. How do I do this
November 1, 2007

Chemistry
sorry it is supposed to say When 23.6 of calcium chloirde CaCl2 was dissolved in water in a calorimeter, the temperature rose from 25.0 degrees C to 38.7 degrees C. If the heat capacity of the solution and the calorimeter is 1258 J/ degrees C, what is the enthalpy change when ...
November 1, 2007

Chemistry
When 23.6 of calcium chloirde CaCl2 was dissolved in water in a calorimeter, the temperature rose from 25.0 degrees C to 21.56 degrees C. If the heat capacity of the solution and the calorimeter is 1071 J/ degrees C, what is the enthalpy change when 1 mol of sodium nitrate ...
November 1, 2007

Chemistry
Ethanol, C2H5OH is mixed with gasoline and sold as gasohol. Use the following to calculate the grams of ehanol needed to provide 293 kJ of heat. C2H5OH + 3O2 ----> 2CO2 + 3H2O Delta H = -1235 kJ How do I do this question
November 1, 2007

Chemistry
Hydrogen H2 is used as a rocker fuel. The hydrogen is burned in oxygen to produce water vapor. 2H2 + O2 ----> 2H2O Delta H = -484 kJ What is the enthalpy change per gram of hydrogen?
October 30, 2007

Chemistry
With a platinum catalyst, ammonia will burn in oxygen to give nitric oxide, NO. 4NH3 + 5O2 -----> 4NO + 6H2O Delta H= -906 kJ What is the enthalpy change for the following reaction? NO + 3/2H2O ---> NH3 + 5/4O2
October 30, 2007

Chemistry
Hydrogen H2, is used asa rocker fuel. The hydrogen is burned in oxygen to produce water vapor. 2H2 + O2 ----> 2H2O Delta H= -484 kJ What is the enthalpy change per gram of hydrogen.
October 29, 2007

Chemistry
Hydrogen sulfide, H2S is a foul smelling gas. It burns to form sulfur dioxide. 2H2S +3O2 ----> 2N2 +6H2O Delta H=-1036kJ Calculate the enthalpy change to burn 26.7 g of hydrogen sulfide.
October 29, 2007

Chemistry
with a platinum catalyst, ammonia will burn in oxygen to gove nitric oxide NO. What is the enthalpy change for the following reaction? NO + 3/2 H2O -----> NH3 + 5/4 O2
October 29, 2007

Chemistry
235 grains (0.0648 g/ 1 grain)(1000 kg/1 g)= 2.52 X 10^3 ft/s (1 m/3.28 feet)= is this the correct set up then where do i go from here
October 29, 2007

Chemistry
A bullet weighing 235 grains is moving at a speed of 2.52 X 10^3 ft/s. Calculate the kinetcic energy of the bullet in joules ahd in calories. One grain equals 0.0648 g. Can someone help me out on this please K. E.= 1/2 mv2 . Convert m to kg Convert ft/sec to meters/second. ...
October 29, 2007

Chemistry
A bullet weighing 235 grains is moving at a speed of 2.52 X 10^3 ft/s. Calculate the kinetcic energy of the bullet in joules ahd in calories. One grain equals 0.0648 g. Can someone help me out on this please
October 28, 2007

Chemistry
-281.0 kJ ( 1 Joules/ 1000 kJ)(1 calorie/ 4.184 Joules)(1 k cal/ 1000 calories) is this the correct set up
October 28, 2007

Chemistry
Hydrogen sulfide H2S is produced during decomposition of organic matter. when .5000 mol H2S burns to produce SO2 and H2O. -281.0 kJ of heat is released. what is this heat in kilocalories. Can you help me start this please
October 28, 2007

Chemistry
3.97m
October 25, 2007

Chemistry
what volume of water must be added to 10ml og 6.0M NaOH to make a solution that is .30 M in NaOH How do I solve for this
October 25, 2007

Chemistry
Chloroform CHCl3, is a volatile liquid solvent. Caculate the density of cholroform vapor at 98 degrees C and 797 mmHg. Give the answer in grams per liter. How do I start this out
October 23, 2007

Chemistry
What is the conversion for kPa to atm What is the conversion for dm^3 to L
October 23, 2007

Chemistry
Magnesium burns in air to produce magnesium oxide MgO and magnesium nitride Mg3N2. Magnesium nitride reacts with water to give ammonia. What volume of ammonia gas at 24 degrees C and 753 mmHg will be produced from 4.56 g of magnesium nitride. P= 753 mmHg (1 atm/ 760mmHg)= .991...
October 23, 2007

Chemistry
An aqueous solution of ammonium nitrate NH4NO2 decomposeds when heated to give off nitrogen. This reaction may be used to prepare pure nitrogen. How many grams of ammonium nitrite must have reacted if 3.75dm^3 of nitrogen gas was collected over water at 26 degrees C and 97.8 ...
October 23, 2007

Chemistry
Calculate the total pressure (in atm) of a mixture of 0.0300 mol of helium, He and 0.0200 mol of oxygen O2 in a 4.00 L flask at 20 degrees C. Assume the ideal gas behavior. Can someone help me start this out... Please
October 23, 2007

Chemistry
Magnesium metal reacts with hydrochloric acid to produce hydrogen gas H2 Mg + 2HCl ----> MgCl + H2 Calculate the volume (in liters) of hydrogen produced at 33 degrees C and 665 mmHg from 0.0840 mol Mg and excess HCl P= .875 atm V= ? n= .0840 mol R= 0.0821 T= 306 K V= nRT/ P...
October 23, 2007

Chemistry
Nitric Acid is produced from nitric oxide, NO which in turn is prepared from ammonia by the ostwald process. 4NH3 + 5O2 -----> 4NO + 6H2O What volume of oxygen at 35 degrees C and 2.15 atm is neeeded to produce 50.0 g of nitric oxide T= 273+35 = 308 K P = 2.15 atm n= 50.0 g...
October 23, 2007

Chemistry
Okay I see where I went wrong
October 23, 2007

Chemistry
A 2.50 L flask was used to collect a 5.65 g sample of propane gas, C3H8. After the sample was collected, the gas pressure was found to be 741 mmHg. What was the temperature of the propane in the flask. P= 741 mmHg(1 atm/760 mmHg)= .975 atm V= 2.50 L n= 5.65 g C3H8 (1 mol/44 g...
October 23, 2007

Chemistry
.985(V)=.177(.0821)(296)= Same thing do you multiply and then divide by .985
October 23, 2007

Chemistry
According to your calculations a reaction should yield 5.67 g of oxygen O2. What do you expect the volume to be at 23 degrees C and 0.985 atm? I got the all the amounts 5.67 g 23 degrees C = 296 K .985 atm And use the ideal gas law Can you help me out by starting it again
October 23, 2007

Chemistry
P(5.00L)= .446 mol(.0821)(292K) It would look like this right then do I just multiply it all together and divide by the 5.00 L
October 23, 2007

Chemistry
In an experiment, you fill a heavy walled 5.00 L flask with methane gas, CH4. If the flask contains 7.13g of methane at 19 degrees C, what is the gas pressure. Use the ideal gas law. Can some one help me get started on this problem please
October 23, 2007

Chemistry
Thanks for all the help DrBob I really appreciate it
October 23, 2007

Chemistry
Sorry it should be 8.58 * 1.020/ 1.584= Answer: 5.525 m^3 Is that right now
October 23, 2007

Chemistry
A driving bell is a container open at the bottom. As the bell descends, the water level inside changes so that the pressure inside equals the pressure outside. Intially the volume of air is 8.58m^3 at 1.020 atm and 20 degrees C. What is the volume at 1.584 atm and 20 degrees C...
October 23, 2007

Chemistry
An experiment called for 4.83 L of sulfur dioxide at 0 degrees C and 1.00 atm. What would be the volume of this gas at 25 degrees C and 1.00 atm? V1= 4.83 L V2= ? T1= 273 K T2= 298 K 1 atm P1 and P2 V2 = V1 * T2/T1 4.83 L * 298 K /273 K = ANSWER: 5.27 L Is this correct.
October 22, 2007

Chemistry
A mole of gas at 0 degrees C and 760 mmHg occupies 22.41 L. What is the at 20 degrees C and 760 mmHg? T1= 273 K T2= 293 K V1= 22.41 L V2= ? 22.41 L * 293 K/ 273 K = ANSWER: 24.05 L Is this the correct answer
October 22, 2007

Chemistry
Is this right??
October 22, 2007

Chemistry
If 456 dm^3 of krypton at 101 kPa and 21 degrees C is compressed into a 27.0 dm^3 tank at the same temperature, what is the pressure of krypton in the tank? V1= 456 dm^3 V2= 27.0 dm^3 P1= 101 kPa P2= ? P2= 101 kPa * 456 dm^3/ 27.0 dm^3 ANSWER: 1705.78 kPa
October 22, 2007

11th grade algebra
Determine the nature of the roots of this question (1/4)x^2+x+1=0
September 27, 2007

Math
Determine the nature of the roots of this question (1/4)x^2+x+1=0
September 27, 2007

Science
Yay! Thanks Liandra!
September 20, 2007

Science
I need one example of a class one lever that is nothing like scissors (eg. pliers, wire cutters...) and has nothing to do with hammers. Thanks.
September 20, 2007

Not Sure
Thanks a lot.
September 7, 2007

Not Sure
What about the bike of yesterday? Like the very first one ever?
September 7, 2007

Not Sure
What year was the first bike invented in? I can't find that information anywhere.
September 7, 2007

English
What is the simple subject and simple predicate in the sentence The first movies were different from today's films. I said the simple subject is movies and the simple predicate is were different. I this the correct answer?
September 6, 2007

math
write equation in standard form. E(-3,-6) and F(-5,-7)
September 6, 2007

sci--check this FINAL ANSWER!
I would construct the building within 200 m from the side near to the logging area, and I would construct the road across the reserve within 110 m from the side of the deforested pastureland. Constructing the building within 200 m from the side near to the logging area would ...
August 22, 2007

sci
I would construct the building within 200 m from the side near to the logging area and the road across the reserve within 110 m from the side of the deforested pastureland. This would help reduce the problem of parasitism by the brown-headed cowbirds by separating them from ...
August 22, 2007

sci
Suppose you are in charge of planning a forest reserve, and one of your main goals is to help sustain locally beleaguered populations of woodland birds. Parasitism by the brown-headed cowbird is an escalating problem in the area. Reading research reports, you note that female ...
August 22, 2007

BIOLOGY
Suppose you are in charge of planning a forest reserve, and one of your main goals is to help sustain locally beleaguered populations of woodland birds. Parasitism by the brown-headed cowbird is an escalating problem in the area. Reading research reports, you note that female ...
August 22, 2007

science
how do the moons stay in orbit around jupiter http://www.synapses.co.uk/astro/moon1.html Thanks
May 7, 2007

Physics
I believe it is as follows: a) x=0 b) y=0 the mag of x would be equal, but in the neg directioin c)x=0 and the mag of x is = to the origional d) all apply except mag of x does not equal 0 as a disclaimer i did not do the math to solve this, but you could use trig to check ...
May 7, 2007

US Gov't
On what two ground have Presidents base their power of Executive privilege ? http://en.wikipedia.org/wiki/Executive_privilege =)
April 26, 2007

US Gov't
What are the provisions of the 25th Amendment? http://www.law.cornell.edu/constitution/constitution.amendmentxxv.html It refers to who would succeed whom in case of the removal, resignation, or death of the President. Let us know if you have further questions. =)
April 25, 2007

Finance
n
April 25, 2007

chemistry
calculate the empirical formula: 79.8%C and 20.2%H. what os the formula Take a 100 g sample. That will give you 79.8 g C 20.2 g H. convert g to mols. mols = g/molar mass. 79.8/12.01 = 6.64 20.2/1 = 20.2 This gives the formula of C6.64H20.2 However, we know from Dalton's ...
March 31, 2007

economics
what happens to the united states economy when the gold standard was discontinued? Since this is not my area of expertise, I searched Google under the key words "gold standard economy discontinue" to get these possible sources: http://www.financialsense.com/...
March 31, 2007

Math - PLEASE
I roll twelve 4-sided dice. What is the probability that I roll at least one 2? What is the probability that I roll exactly three 2s? i dont knowm sorry the same question was answered by Economist at 4:59
March 29, 2007

Math - Statistics
I roll 12 4-sided dice. What is the probability that I roll at least one 2? What is the probability that I roll exactly three 2s? So i take it, on any give roll, the probability of rolling a 2 is .25 (25%); the probability of rolling something else must be .75 The probability ...
March 29, 2007

science
For the following crystals, explain how their melting points are related to the bonding forces and the crystal structure. a)Copper,Cu b)Water,H20 c)Sodium chloride,NaCl d)Diamond,C (Broken Link Removed)
March 25, 2007

math
find all solutions in the interval [0,2 pi) sin(x+(3.14/3) + sin(x- 3.14/3) =1 sin^4 x cos^2 x Since sin (a+b) = sina cosb + cosb sina and sin (a-b) = sina cosb - cosb sina, the first problem can be written 2 sin x cos (pi/3)= sin x The solution to sin x = 1 is x = pi/2 For ...
March 22, 2007

math
tan (u-v) given sin u=3/4 and cos v= -5/13 with U and V in quadrant 2 Use the identity tan (u-v) = (tanu tanv)/[1-tanu tanv) Get the values of tanu and tanv from the sines and cosines that you are given. For example, if cos v = -5/13, sin v = 12/13 and tan v = -12/5 (in the ...
March 22, 2007

social studies
what do people who live in mozambique wear on their day to day activities http://www.google.com/search?source=ig&hl=en&q=mozambique There are all kinds of sites to sift through here. If you find nothing, you might try refining the search to mozambique everyday clothing. =)
March 6, 2007

Science
What is the smallest part of a compound?
February 20, 2007

drugs
Help! An inhalant is not a stimulant or a depressant. So... what is it then?????? Puh-leaze help me! My grade this term counts on it. What kind of inhalant? We inhale many things -- dust, illegal drugs, legal asthma medications, pollen, etc. Please clarify your question. ...
February 19, 2007

Health (drugs)
I know that inhalants aren't either a stimulant or a depressant. So what are they? Thank you for using the Jiskha Homework Help Forum. Here is a site from the government explaining inhalants: http://www.nida.nih.gov/Infofacts/Inhalants.html thanks, but I couldn't find ...
February 19, 2007

Gauss' Law!!!!!!!!!!
Can any one help me for this problem? The cube in Figure 23-27 has edge length 1.40 m and is oriented as shown in a region of uniform electric field. Find the electric flux through the right face for the following electric fields, given in newtons per coulomb. (the figure is ...
February 14, 2007

American Government
Does it matter if the Federal government or the state governments get to decide if the Federal government exceeded its authority? If yes, how? If the federal government decides if it has exceeded its authority, then obviously it's going to decide that it hasn't. The ...
February 9, 2007

Plz Help Physics
We know that the negative charge on the electron and the positive charge on the proton are equal. Suppose, however, that these magnitudes differ from each other by 0.00011%. With what force would two copper pennies, placed 1.4 m apart, repel each other? Assume that each coin ...
February 4, 2007

spelling
you rock people who gave all the answers to me i have to go bye!!!!!!see you next time and i am definently coming back to this awesome website bye!!!!
January 16, 2007

english (especially for Writeacher)
Lynch, T. (1996). DS9 trials and tribble-ations review. Retrieved October 8, 1997, from Psi Phi: Bradley's Science Fiction Club We b site: h t t p: / /w w w .bradley. edu /campus org/psiphi/DS9/ep/ 503r . html ... and this will go immediately after the quotation or ...
December 21, 2006

english
How do you cite a website in a paper? I know it is in parentheses, but that is pretty much all I know. citing websites (Broken Link Removed) http://www.jiskha.com/display.cgi?id=1166411079.1166414090 So are you saying I should put all of this: Lynch, T. (1996). DS9 trials and ...
December 19, 2006

Physics
if ur on about somthing else sorry but there are 1000grams im a killogram
December 8, 2006

science
these are my homework questions can you answer any???there are 4 1 A pupil placed some magnesium in a gas jar of oxygen How could the rate of reaction between these substances be increased 2 Complete the word equation for the reation magnesium and oxygen 3 How does the colour ...
November 29, 2006

math
what is an example of a positive corralation using a scatter graph? please help!!!!!!!!!!!!!!!!!!!! I don't know how to place that image in this reply. However, I will try to describe it. If both the abscissa (horizontal or X axis) and the ordinate (vertical or Y axis) ...
November 29, 2006

History
What problems did the Israelites face when they returned to Canaan? This is a religious, rather than a historic question. Please check your book or the Bible for the answer your teacher expects. As there is no physical historical evidence for Any of the events in the bible, ...
October 24, 2006

music scales
Hi, I need to play scales for my orchestra grade throughout the year. Is there an online site that has the (actual) scales on it along with the arpeggios? Thank you so much for your help. (The 12 major scales) I think this site will help you with that. http://www.8notes.com/...
October 19, 2006

nucleus true facts
Wow, BRANDON. You have absolutly NOOOOOOOOOOOOOO LIFE WHAT SO EVER. Ha, little boy. c[:
October 4, 2006

pre-calculus
pi*(200^2)^2
October 3, 2006

Math
A train track is 5280ft. long. After adding another foot of track, an arc is created. What is the height of the arc and how would i measure it? FIND THE LEAST COMMON MULTIPLE OF 6,9 The maximum height is given by [2640(5280) + h^2 = [2640(5280) + 0.50]^2^2 making h = 1.94 ft. ...
September 28, 2006

Physics
A rock is dropped from a height of 100m. a) how long does it take to fall the first 50m? b)How long does it take to fall the last 50m? Which equation would I use to solve this problems with? For a) use s=(1/)g*t^2 where s=50m and g=9.8m/s^2 and solve for t. For b)use s=(1/)g*t...
September 19, 2006

english
perks of being a wallflower. Does anyone know any symbols in that book? email or respond:
September 6, 2006

math
Thank goodness for this site! Two questions: first: in the 1990 U.S. census, the final count was 248,709,873 people. The general population is estimated to have been undercounted by 1.8%, that is, only 98.2% of the people were counted. If this were the case, what was the ...
August 28, 2006

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