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August 21, 2014

Posts by jake


Total # Posts: 1,717

AP CHEMISTRY
The unit cells for most alkali metal halides are face-entered for both the cations and anions. In the case of NaCl the sodium ion is just a little too large for the chloride ions to touch each other along the face diagonal. The unit cell edge length is 564.0 pm. The sodium ion...
January 24, 2008

science
for what?
January 16, 2008

Biology
thanks
January 12, 2008

Biology
I know that the phosphate [cells] and sodium barcarbonate [blood plasma] buffer systems are two examples of biological buffers; however, i am writing an essay for bio and i need a third example. does anyone know of a third biological buffer system?
January 12, 2008

Science
Why is is it important to place your arm in a horizontal position rather than letting it hang down at your side when you take your blood pressure? Does everyone's heart create the same pressure? Why or why not?
January 12, 2008

Science
A fish is homozygous dominant for bug eyes and his mate is heterozygous. show the possible offspring. i have BB BB Bb and Bb for the possible offspring, but how do I express this phenotypic ratio? would 4:0 correct?
January 9, 2008

Chemistry
If I have to make a solution with sodium bicarbonate (baking soda) how do i find the molarity and how do i correctly make the solution??? i.e. how do i prepare a solution of sodium bicarbonate with a molarity of 0.01?
January 8, 2008

math
Damon I really dont understand please one hint.mt mom does not understand either
January 7, 2008

math
One number in each group does not fit 66,90,32,45,300 Pattern? 99,981,459,89,729 Pattern? 128,244,556,788,762 Pattern
January 7, 2008

math
12,18,15,21,18,24,21,27,24,30,27,34 13,26,18,36,23,36,28,41,33,46,38,51 44,54,47,57,50,60,63,73,66,76,69,79,72, 15,14,15,24,25,34,35,44,45,54,55
January 7, 2008

math
complete the pattern 12,18,15,21,18,?,?,?,?,?,?, 13,26,18,36,23,?,?,?,?,?,?,?, 44,54,47,57,50,?,?,?,?,?,?,?, 5,14,15,24,25,?,?,?,?,?,?,?,?
January 7, 2008

Math
How do i find the equation of a parabola in the form ax^2+bx+c?
January 7, 2008

AP CHEM
An ice cube tray contains enough water at 22.0 C to make 18 ice cubes that each have a mass of 30.0g. The tray is placed in a freezer that uses CF2CL2 as a refridgerant. The heat of vap of CF2CL2 is 158 J/g. What mass of CF@CL2 must be vaporized in the refridgeration cycle to ...
January 2, 2008

AP Chemistry
Thank you!
January 2, 2008

AP Chemistry
I was wondering if anyone could possible help me with this homework question? The normal boiling point for acetone is 56.5 degrees C. At an elevation of 5300 ft the atmospheric pressure is 630. torr. What would be the boiling point of acetone (deltahvap = 32.0 kJ/mol) at this ...
January 2, 2008

What is discrete math? And is it relatively easy?
I ask because my TA recommended taking it next semester along with calc 3. My major is electrical engineering, and I might throw actuarial science into the mix too. So yeah, lots of math.
December 18, 2007

French
thats right
December 10, 2007

Math
why does the president put vegtables in his blender?
December 9, 2007

physics
i dont get it
December 4, 2007

How do you use the substitution method in math?
Example: 2y + x = 3 (1) 4y – 3x = 1 (2) Equation 1 looks like it would be easy to solve for x, so we take it and isolate x: 2y + x = 3 x = 3 – 2y (3) Now we can use this result and substitute 3 - 2y in for x in equation 2: Now that we have y, we still need to ...
November 28, 2007

Biology
they have exoskeletons?
November 27, 2007

English (Classical Myths)
I have a myth project assigned. I got lucky (or so I thought) and had the myth of Polyphemus. Wikipedia has it if anyone doesnt know it. There are three things that I need for my project: 1) The moral of the story. 2) How the story explains natural phenomenon. 3) How the myth ...
November 27, 2007

biology - requirements of diffusion?
Im pretty sure its D because I think both A and C are needed and B sounds logical.
November 27, 2007

Math
oh lol, first I looked at this question and I was like wow, this is impossible to do because I thought you were asking for the COMMON factor for all of those... in the case of factors of each individual #... it should take you less than 5 minutes to do them... so you have ...
November 20, 2007

math
please help! find 3 consective numbers with a sum of 12. find three consective numbers with a sum of 45
November 20, 2007

College Algebra ~ Please Help
Anything related to projectile is related to quadratic. Examples can range from shooting a bullet like the example above to a simple action such as throwing a baseball upward. You can use quadratic to figure out what is the maximum height your ball will goes up to, what's ...
November 20, 2007

biology
umm... aren't they both contain DNA and DNA is made out of nitrogenous base and phosphate backbone? So I would say nitrogen and phosphorous.
November 19, 2007

Algebra/Trigonometry
huh? what is this? lol... 1/y-1/y = 0... then -3 = -3 duh?
November 18, 2007

Chemistry
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6
November 18, 2007

Chemistry
Not 100% sure, but I say it's D. I think there are only 4 orbitals: s(2), p(6), d(10), f(18).
November 18, 2007

Biology
In glycolysis, Acetyl-CoA is recycled so it can be used again for another cycle or elsewhere for biosynthesis.
November 18, 2007

science
Efficiency can never reach 100% because there's always loss of energy during the process of carrying out work. One example is energy loss because they're converted into heat while operating.
November 16, 2007

math
Okay, this one you really really should plot out the coordinates. It will give you an approximate orientation of the line. If plotted it out and realized that ST is a diagonal segment with a POSITIVE slope (meaning it goes up from left to right, that let you know that the y ...
November 13, 2007

math
No, I didn't say D is (3,-1). The question asks you for 3 points on the segment CD that will divide that segment to 4 pieces equally. I'm just saying that the CLOSEST point to CD is (3,-1) just to correct what drwls said. The 3 points on the segment CD are (3,-1), (3,2...
November 13, 2007

math
Just plot out the two points and connect them and count the number of squares on your graphing papers to find the length. You should have 12 squares total in length if you drew in correctly because (8+|-4|) =12. Now you need to divide that into 4 equal parts so do 12/4 = 3 ...
November 13, 2007

math
3^2 is where I get the +9 from... the -6x is from (-3x)+(-3x). Solution = (-2,-1),(8,-1).
November 13, 2007

math
13^2 mean "13 square" or "13 x 13" or "13 raise to the power of 2". You have to square both sides of the equation to cancel off the "square root" on the right side of the equation so you can figure out "x", not "square ...
November 13, 2007

math
All right... so you have two points (x,-1) and (3,11) this is correlating to (x1,y1) and (x2,y2)in the distance formula. d = sqroot [(x2-x1)^2 + (y2-y1)^2] Plug in the numbers and you'll have: 13 = sqroot [(3-x)^2 + (11-(-1))^2] 13^2 = x^2-6x+9 + 12^2 169 = x^2-6x+153 0 = ...
November 13, 2007

math
I replied you, but I can't see it down here. Click on your first post of your question to view it.
November 13, 2007

math
Okay, to do all these problems relating to point coordinates. The first thing you do is to plot those points on the graph so you can have a clear picture of what it looks like. That's just a hint although you might be able to do this without plotting it, but it will be ...
November 13, 2007

math
Maybe re-wording this question will help you out. Find the distance between two points: a)(-4,3) and (5,-4) b)(-3,-2) and (3,5) I'm sure your teacher gave you this formula: d = sqroot [(x2 - x1)^2 + (y2 - y1)^2] where x and y are defined as (x,y) in the coordinate. x2 just...
November 13, 2007

Chemistry - Kinetics
a) Yes, you can probably tell because the activation energy gets lower and thus allow the reaction to speed up way faster than without a catalyst... it's kind of dumb to ask if in catalyst is involved in a CATALYZED reaction... b) No, the catalyst will get recycled at the ...
November 13, 2007

Genetic
I need to write a proposal of the possible traits we can actually measure in lab. What are some quantatitive traits of woodlice/isopod beside measuring their maximum speed.
November 13, 2007

math
What do you mean by "how would be the answer"? The answer to this problem is 1.
November 7, 2007

math
At 4:00 Joe's thermoter read 30C. He put it in the freezer and read it every 5 minutes. At 4:05pm, the temperature was 23C. At4:10pm the temperature was 16C.The pattern continues, when will the temperature be below 0C?
November 5, 2007

Evolution
In an experiment using quantitative genetic approaches to investigate the evolution of butterfly eye-spots as a model system for understanding development. There are 3 groups of butterfly populations: small (mean diameter = 2.6 mm), intermediate (3.4 mm), and large eyespots (3...
November 5, 2007

Algebra 2
The way I think of "range" is the possible values of the y-axis on your graph. The easiest way to see this is to actually enter the function into your graphing calculator and graph it out. In your example, you have a straight line with a slope of -1/3, so basically ...
November 5, 2007

math
how many possible 3 digit numbers are there that have a middle zero? how many possible 4 digit numbers are there that have two middle zeros? Explain your answears
November 4, 2007

CHEMISTRY
I don't even understand how this question works. How do I solve it? A microwave oven heats by radiating food with microwave radiation, which is absorbed by the food and converted to heat. suppose an oven's microwave is 13.7 cm. a container w/ 175 mL of water was placed...
October 31, 2007

IB Math Studies
Would it be appropriate to use a chi-square test for analysis of statistics in the following topics? •Number of Surgical Fatalities vs. U.S. State •Number of professional men’s soccer injuries vs. country of their team
October 28, 2007

AP US History
compare the rebellion of the american revolution to the rebellion of the civil war
October 28, 2007

CHEM-HELP!!!!
help? how do i calculate the heat of formation of a solid? i only know how to find the heat of formation of a liquid. here's what i have so far. delta t= 16.8 degrees c mass= 33.136 g cp = 4.184 j/g degrees c m cp delta t = -2329J (process is exothermic) what do i do now?
October 24, 2007

English
Does anyone recall the mythical beasts that were described on the map in Ondaatje's Running in The Family, the chapter entitled Tabula Asiae? I left my book in my locker ;/
October 24, 2007

Chemistry
Zinc is often used to calibrate calorimeters because it undergoes a very sharp phase transition from the solid to the liquid at 419.5°C. Calculate the enthalpy change when 5 g of zinc metal is heated from 100°C to the point where the entire sample is melted. (The heat ...
October 23, 2007

Math
If you say "10 less than y". Does it mean 10-y or y-10. Which is correct and why?
October 17, 2007

CHEMISTRY
If 142.38 g of l water at 21.7 degrees C is placed into a syrofoam cup with 174.36 g of ice at -27.5 degrees C what would be the final temperature of the entire contents at equilibrium? If it is partially frozen, how many g of the ice has melted? given values cp water = 4.184 ...
October 14, 2007

computer class (please look!!!)
use google book search to find the first line of page 3 in the book 'curious george goes to a chocolate factory' [sorry to make you do this hw but my internet is not fast enought to load this page] thx ^^!
October 2, 2007

Chemistry
2 HCl (aq) + Ba (OH2) (aq) ----> BaCl2 + 2 H20 (l) deltaH = -118 kJ Calculate the heat when 100.0 mL of 0.500 M HCl is mixed with 300.0 mL of 0.100 M Ba(Oh2). Assuming that the temp. of both solutions was initially 25.0 degrees C and that the final mixture has a mass of 400...
October 1, 2007

CHEMISTRY
A 2.75 g sample of the hydrocarbon acetone, CH3COCH3, is burned in a bomb calorimeter with 975 mL of water, initially at 23.50 degrees celsius. The bomb is constructed of 285.0 g of nickel metal having a specific heat capacity of Cp = 0.826 J/ g degrees C. The final ...
September 30, 2007

Ap Chemistry
Posted by Jake on Sunday, September 23, 2007 at 1:08pm. My objective is to find the molar volume of a gas. Is this the correct balanced equation for magnesium ribbon reacting with hydrochloric acid to form hydrogen gas? 2Mg (s) + 2HCL (l) ----> H2 (g) + 2MgCl (aq) Also, I&#...
September 25, 2007

AP Chemistry
Thanks, sir. This is what I did, could you tell me if its correct? given value 1.072 g/meter 1.072 g/m X .02 m [the magnesium ribbon was 2.0 cm] = 0.02144 gMg Then to find the moles of H2: 0.02144 g mg ( 1 mol Mg/24.31 g Mg) (2 mol H2/1 mol Mg) = 1.76 X 10^ -3
September 23, 2007

AP Chemistry
My objective is to find the molar mass of a gas. Is this the correct balanced equation for magnesium ribbon reacting with hydrochloric acid to form hydrogen gas? 2Mg (s) + 2HCL (l) ----> H2 (g) + 2MgCl (aq) Also, I'm required to find the mass of the magnesium ribbon in ...
September 23, 2007

Economics
economics
September 22, 2007

pigskin geography
i dentifly the panhandle state the the seattle seahaw will fly over going to their game
September 19, 2007

american history
What were republicans plans to do about Roosevelt not following through with things he said he would do? like not using the bullypullpit and stuff. PLEASE HELP!
September 15, 2007

science
how do u convert tons into kilograms?
September 13, 2007

Chemistry
Carminic acid,a naturally occuring red pigment extracted from the cochineal insect, contains only C,H,and O. It was commonly used as a dye in the first half of the nineteenth century. It is 53.66% C and 4.09% H by mass. A titration of the 0.3602 g sample pf the carminic acid ...
August 27, 2007

physics- electrodynamics
can someone walk me through this --- you'd be a lifesaver a rectangular pipe running parallel to the z axis(-‡ to +‡) has 3 grounded metal sides at y=0, y=a and x=0. the fourth side at x=b is maintained at a specified potential v0(y). a. Develop a ...
August 5, 2007

science
Are there any related structure from an asprin? To show how important an asprin is from using a carboxylic acid. You need to clarify your question. I need to produce a related structure of the molecular features of carboxyli acid, size hydrocarbon group on ester and distance ...
July 12, 2007

social
Do poor people have the same expectations in life as rich people> Expectations for what? Life goals? What's for dinner tomorrow? Their golf scores? Geeze kido, can you narrow it down a bit? It also depends on which poor people you are discussing. If poor people are ...
May 17, 2007

spanish
Did evita help the ppl of argentina..who did she help and how so? and Who did she hurt in her endeavors Thank you for using the Jiskha Homework Help Forum. Here are some sites for Eva Duarte Perón: 1. http://www.evitaperon.org/ (You can see and hear her here.) 2. http://...
May 16, 2007

physics
Can someone check these? 1. What device, developed in 1970, is able to make images of individual atoms? 1. The X-ray crystallographer 2. The laser 3. The Brownian motion detector 4. The scanning electron microscope My answer: 4 2. Which of the following is smallest? 1. Proton ...
May 8, 2007

health
This isn't a school question, this is for my own understanding. I'm thinking about majoring in it. What is the difference between a respiratory care person and a respiratory therapist? I think they are the same. And could someone tell me what goes into the job of ...
May 6, 2007

English
Could someone please help me make this feature article flow and be enticeing to the reader? With winter on the horizon, many Australians are again facing the prospect of drought. If there isn’t a better than average rain season this year many Australian farmers will be ...
May 5, 2007

math,correction
1/2(y-10)+y distributive propertys
April 19, 2007

chem
A solution contains 32 g of KNO3 per 100g of water at 25 degree C. Is the solution unsaturated, saturated, or supersaturated? I think its saturated Look at your saturation chart. I will be happy to critique your thinking. is there one online?
April 5, 2007

physics
When you hold your hand palm-up, the atmosphere exerts a force of about 800 N on the palm of your hand. Comparing this force with I. the force on the back of the hand, II. the force on the palm when you are holding your hand vertical, III. the force on the palm when it is palm...
February 27, 2007

Complex numbers
For the transformation w=(z+i)/(z-i) show that as z moves along the real axis, w moves along a circle centre O and radius 1 I do not know where to start changing it to polar form will help w=magnitude @ (arctan 1/z - arctan -1/z) where magnitude is sqrt (z^2+1)/(z^2+1) or w= 1...
February 24, 2007

Maths again
For the transformation w=z^2, show that as z moves once round the circle centre O and radius 2, w moves twice round centre O radius 4. I am okay finding the radius and centre of the locus but how do I show it moves twice roundfor w for z turning once. See my other post. ...
February 24, 2007

Maths
For the transformation w=z^2, find the locus of w when z lies on the imaginary axis. I thought the locus would be a line along the real axis as I thought w= r^2 or -r^2 but the book says it has argument pi which would mean only on the negative real axis ie w= -r^2 why both are...
February 24, 2007

maths
For the transformation w=z^2, find the locus of w when z lies on the imaginary axis. I thought the locus would be a line along the real axis as I thought w= r^2 or -r^2 but the book says it has argument pi which would mean only on the negative real axis ie w= -r^2 why both are...
February 23, 2007

maths complex numbers
Can abs(28-7w)=7abs(w) be written as abs(w-4)=abs(w) and if so why surely it should be abs(4-w)=abs(w) can any one explain why I can just chane the signs Yes, it can be written that way. I dont see that you have changed any signs, you factored a postive seven out of both sides...
February 23, 2007

physical science
How to learn to do the formulas for finding speed, distnace, and etc.?? *w*w*w*.*a*s*k*.*c*o*m* hey i cant help but heres a hint just go 2 (go on the words w/ the stares around them )and ask the question *w*w*w*.*a*s*k*.*c*o*m* hey i cant help but heres a hint just go 2 (go on...
February 21, 2007

calculus
a bacteria pop. grows exponentially. There are 1500 bacteria after 3 hours and 20,000 after 8 hours. ahving trouble finding the initial bacteria pop. thanks for the help In five hours the population get's larger by a factor 13 + 1/3-----> N(t) = N_0 * (13 + 1/3)^(t/5 ...
February 15, 2007

Maths- complex numbers
Find tan(3 theta) in terms of tan theta Use the formula tan (a + b) = (tan a + tan b)/[1 - tan a tan b) in two steps. First, let a = b = theta and get a formula for tan (2 theta). tan (2 theta) = 2 tan theta/[(1 - tan theta)^2] Then write down the equation for tan (2 theta + ...
February 13, 2007

Maths
Find tan(3 theta) in terms of tan theta
February 12, 2007

unscrambling a word
unscramble hautis hiatus
February 5, 2007

Maths
Given that arg((z-1)/(z-2i)) = pi/4 describe the locus of P and sketch this on an argand diagram. Show that the point (1,3) lies on this locus. I know it is an arc subtended from the points (0,2) and (1,0) but I do not know how to find the centre of the circle which I am ...
February 5, 2007

Maths
Given that arg((z-1)/(z-2i)) = pi/4 describe the locus of P and sketch this on an argand diagram. Show that the point (1,3) lies on this locus. I know it is an arc subtended from the points (0,2) and (1,0) but I do not know how to find the centre of the circle which I am ...
February 4, 2007

Maths
Given that arg((z-1)/(z-2i)) = pi/4 describe the locus of P and sketch this on an argand diagram. Show that the point (1,3) lies on this locus. I know it is an arc subtended from the points (0,2) and (1,0) but I do not know how to find the centre of the circle which I am ...
February 4, 2007

Social Studies Question
what is our environment?
February 2, 2007

Statistics
Check my answers please! Thanks a lot. Five students reported that the previous night they slept: 7,8,7,10,9 hours. Calculate the sample varience and standard deviation. sample varience = 1346.5 standard deviation = 36.7 Consider this. Ths standard deviation can never be ...
February 1, 2007

math
i need to integrate: (secx)^4 dx let u = sec x dv =sec^3 x dx Start with this. Then, you will have to deal with the integral of sec. You should be able to solve it after a few steps. Looks a little messy.
February 1, 2007

Math -
What would the interval be for a bar graph with the following data: 104,135,124,144,122 Highest number minus lowest number 144-104 = 40
January 25, 2007

HELPPPPP
A diver descends from a salvage ship to the ocean floor at a depth of 35 m below the surface. The density of ocean water is 1.025x10^3 kg/m^3. a) Calculate the guage pressure on the diver on the ocean floor. b) Calculate the absolute pressure on the diver on the ocean floor. ...
January 21, 2007

analogies
insurmountable: disadvantage Choices impermeable:water indomitable:defeat interminable:tedium inevitable:drawback insuperable:barrier and a sentence to prove How to solve analogies: http://www.teachervision.fen.com/vocabulary/reading-comprehension/6697.html Use with http://www...
January 15, 2007

maths 2
The original question I had was write arcsin4 in the form a+ib. I manage and understand how to get so far BUT How do I get from cosacoshb-isinasinhb=4 to 2m(pi)+/- iarccosh4 arcsin4 = a + b i ---> 4 = sin(a + bi) sin(a + bi) = sin(a)cos(bi) + cos(a) sin(bi) cos(bi) = cosh(...
January 14, 2007

Maths
How do I write arcsin4 in the form a+ib. I know the answer but do not Know how to get to it Take sinus of both sides: 4 = sin(a)cosh(b) + i cos(a)sinh(b) Equate real and imaginary parts. You then see that you can put a = pi/2. And it then follows that b = arccosh(4) Thanks for...
January 14, 2007

HELP
How United States and United Nation helping for Darfur? Please give me each exsample about Money, Aid and Military. And Is it enough? I already know US and UN gave Darfur some troopes, but I don't know Money and Aid. Essentially, the U.S. has not helped in Darfur.
January 11, 2007

Government
Why other countries (like Unites states, united nations) shold help victims in genocide of darfur? Because there are African nations. Couldn't African Nations help victims? Some African nations are helping the victims, but it doesn't look as though they are very ...
January 7, 2007

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