Tuesday

March 3, 2015

March 3, 2015

Total # Posts: 1,815

**math**

Suppose x is a random variable with mean and standard deviation. If a large number of trials is observed, at least what percentage of these values is expected to lie beween mean-2(standard deviation) and mean + 2(standard deviation) could someone help me i'm so lost? thank...
*April 9, 2009*

**question**

does arm has the same vowel sound as jar
*April 1, 2009*

**8th Grade Science**

how does the length of the sun's path vary with the seasons?
*April 1, 2009*

**Math**

Divide by long division divide x^3+4x^2-3x-12 by x^2-3 I am a bit confused. Please explain!!
*April 1, 2009*

**college algebra**

x and y intercept of y=x^3+7x^2+10x
*April 1, 2009*

**english**

how did the cat catch the mice? isn't that a sentence?
*March 31, 2009*

**english**

thanks will do
*March 31, 2009*

**english**

does found as the same vowel sound as down?
*March 31, 2009*

**word analysis**

thanks
*March 31, 2009*

**word analysis**

spoil
*March 31, 2009*

**word analysis**

which word has the same vowel sound as join? tool joke spoil cold
*March 31, 2009*

**Physics**

On August 20, 1989, in Cologne, West Germany, Said Aouita of Morocco also established a world record when he ran the 3000 meter run in 7.00 minutes 29.45 seconds. What was his average speed (in m/s) for the race? Do I divide 3000 by 7 minutes and 29.45 seconds?
*March 29, 2009*

**Physics**

In 1989, Carl Lewis established a world record when he ran the 100 meter dash in 9.92 seconds. What was his average speed(in m/s) for the race? Remember to include your data, equation, and work when solving this problem. I am not sure how to do this problem. Please help!!
*March 29, 2009*

**Math**

Use the functions f(x)=x+4 and g(x)=2x-5 to find the specified functions. (g x f)^-1
*March 25, 2009*

**chem**

What is the conjugate acid of H2PO4-? (Type your answer using the format format [H2PO4]- for H2PO4- What is its conjugate base? i have no cluee thanks
*March 20, 2009*

**english**

thanks but i dont have to write one i have to find 1 about the religion, like i know scholarly articles are written by experts about a certain subject but how do i find one an article by experts on religion? by the way last time i used a website my teacher said it wasnt a ...
*March 16, 2009*

**english**

What is a scholarly article and how can i find one about the importance of religion in the 1600's, or around the time of Shakespeare.
*March 16, 2009*

**Chemistry**

Pre-Lab Questions Data: [mass of copper wire] 0.738 g [standard solutions] solution 1: 0.738 g of copper wire dissolved in 50.00 mL solution solution 2: 1:2 dilution of solution 1 solution 3: 1:4 dilution of solution 1 [absorbance data at lambda(max)] solution 1: 0.740 ...
*March 16, 2009*

**Chemistry**

would i get a more accurate answer using the slope instead of a point at random?
*March 11, 2009*

**Chemistry**

For example, if I pick a point at random on the graph.. say (0.200, 184.3). Then R1 = volume H2 / mass Mg R1 = 184.3 mL H2 / 0.200 g Mg R1 = 921.5 mL H2 / g Mg for the next part it says "using the value of R1" so... R2 = (184.3 mL H2 / 0.200 g Mg) * (1 mol Mg / 24.31...
*March 11, 2009*

**Chemistry**

I'm about to do the second part of a Limiting Reagent laboratory tomorrow. There are a few questions that are giving me trouble on the pre-lab assignment. In the first lab period, we measured the amount of H2 gas produced in a reaction of Mg and 10 mL of 2.0 M HCl. We ...
*March 11, 2009*

**Chemistry**

Given: Mg + 2HCl --> H2 + MgCl2 0.250 g of magnesium reacts with 10.00 mL of 1.5 M HCl. What volume (in mL) of H2 gas is produced?
*March 11, 2009*

**Chemistry**

Heat Capacity at constant volume: CV = (partial q / partial T) with V constant since volume is constant, work is zero and dq = dU, so CV = (partial U / partial T) with V constant Delta U = CV * Delta T Does this final relationship hold during a reaction where volume is NOT ...
*March 4, 2009*

**Chemistry**

typo... "The molarity of the NaOH solution is 0.160." The number in the calculations is correct.
*March 4, 2009*

**Chemistry**

Thank you very much. The molarity of the NaOH solution is 0.162. So I did the following: 25.00 mL NaOH*(1 L / 1000 mL)*(0.160 mol NaOH / 1 L NaOH)*(1 mol CH3COOH / 1 mol NaOH) = 0.004 mol CH3COOH (0.004 mol CH3COOH / 5.00 mL) * (1000 mL / 1 L) = 0.8 M CH3COOH Now I'm ...
*March 4, 2009*

**Chemistry**

Calculate the molar concentration of acetic acid (CH3COOH) in a 5.00-mL sample of vinegar (density is 1.00 g/mL) if it is titrated with 25.00 mL of NaOH.
*March 4, 2009*

**Chemistry**

Could someone please direct me to a website that explains why acid-base titration is a useful technique in chemistry. Or offer your own opinions. Thanks ahead of time for any input!
*March 4, 2009*

**Chemistry**

Acid-Base Titrations a) How will the concentration of NaOH be affected if during the titration some of the solid potassium hydrogen phthalate was spilled during the transfer? Will the concentration of the standardized NaOH increase, decrease, or have no effect? b) How will the...
*March 3, 2009*

**Chemistry**

No, this is not a duplicate. The other question refers to molarity. This one is asking for molar mass of an unknown acid. For this question would I do the following... Start with the volume of NaOH then convert it to moles with the answer from the first question. Use ...
*March 2, 2009*

**Chemistry**

Include an explanation, balanced chemical equation, units, significant figures and/or calculations where appropriate. Determination of the Molar Mass of an Unknown Acid Trial 1: 0.499 g unknown acid 24.07 mL NaOH Trial 2: 0.501 g unknown acid 23.71 mL NaOH Trial 3: 0.500 g ...
*March 2, 2009*

**Chemistry**

I'm not sure how to start it. I know I need to have a balanced chemical equation, so... KHC8H4O4 (aq) + NaOH (aq) --> H2O (l) + ???? Then once I figure this out, do I use the mass in each trial to find the moles of NaOH through stoichiometry. Then divide the number of ...
*March 2, 2009*

**Chemistry**

Include an explanation, balanced chemical equation, units, significant figures and/or calculations where appropriate. Standardization of NaOH Solution Trial 1: 0.501 g KHC8H4O4 15.22 mL NaOH Trial 2: 0.503 g KHC8H4O4 15.11 mL Trial 3: 0.500 g KHC8H4O4 15.10 mL Using the data ...
*March 2, 2009*

**math**

To write a decimal as a percent, just multiply it by 100. 0.3246 * 100 = 32.46%
*March 2, 2009*

**Gen. Chemistry**

A 0.887 g sample of a mixture of NaCl and KCl is dissolved in water and the solution is treated with an excess of AgNO3 producing 1.822 g of AgCl. What is the percent by mass of each component in the mixture?
*March 2, 2009*

**calculus**

Use integration by parts to evaluate the definite integral. Intergral: xsec^2(6x) dx I set u=sec^2(6x) and dv=x, but the problems seems to get harder as I go on.
*February 27, 2009*

**3rd grade**

5 / 10 = ? / 20 Multiply the denominator by 2 to get 20. Multiply the numerator by the same number (2) to get 10. Answer: 10 / 20
*February 19, 2009*

**Chemistry**

If 150 mL of 1.73 M aqueous NaI and 235 g of Pb(NO3)2 are reacted stoichiometrically according to the balanced equation, how many grams of Pb(NO3)2 remain? Pb(NO3)2(aq) + 2NaI(aq) → PbI2(s) + 2NaNO3(aq) Molar Mass (g/mol) NaI 149.89 Pb(NO3)2 331.21 Density (g/mL) - Molar...
*February 19, 2009*

**Chemistry**

What volume of 0.1209 M HCl is necessary to neutralize 0.5462 grams Ca(OH)2? Include a balanced chemical equation.
*February 19, 2009*

**Chemistry**

A 0.2861 gram sample of an unknown acid (HX) required 32.63 mL of 0.1045 M NaOH for neutralization to a phenolphthalein endpoint. What is the molar mass of the acid?
*February 19, 2009*

**Chemistry**

In a acid-base titration, 22.81 mL of an NaOH solution were required to neutralize 26.18 mL of a 0.1121 M HCl solution. What is the molarity of the NaOH solution?
*February 19, 2009*

**Chemistry**

I'm going over some post-laboratory questions for Conductivity of Solutions. One of the questions is... From your measurements, what can you say about a) the presence of ionic impurities in tap water? b) the presence of molecular impurities in tap water? I measured the ...
*February 18, 2009*

**URGENT MATH help**

(x^2y^6-3)^2 .....PLEASE HELP ME I HAVE NO IDEA HOW TO SOLVE THIS IVE BEEN DOING IT FOR HOURS
*February 18, 2009*

**math**

never mind what i figured that out but i cant seem to figure this out (x^2y^6-3)^2 .....thanks for your help i really need it
*February 18, 2009*

**math**

hi what is what is (x^-3)^2
*February 18, 2009*

**math**

What is (x^2y^6-3)^2
*February 18, 2009*

**math**

Is (5(x+1)/3) ....a simplified answer or is it (5x+5)/3 sorry i forgot the parenthesees so it might have looked confusing!
*February 18, 2009*

**math**

is 5(x+1)/3 ....a simplified answer or is it (5x+5)/3
*February 18, 2009*

**math-fractions**

I have to rewrite the fraction without an exponent, but I'm not for sure how to do the negative exponent. pls help! (3/2)^-2
*February 16, 2009*

**AP Chem**

A 0.23 M sodium chlorobenzoate (NaC7H4ClO2) solution has a pH of 8.68. Calculate the pH of a 0.23 M chlorobenzoic acid (HC7H4ClO2) solution
*February 15, 2009*

**chemistry**

Calculate the mass of the solid you must measure out to prepare 100 mL of 0.025 M CuSO4. Note that this salt is a hydrate, so its formula is CuSO4⋅5H2O. You must include the waters of hydration when calculating the formula weights. Would the following set-up yield the ...
*February 11, 2009*

**english**

what are some similarities between the stories Where are you going where have you been and the story Young Goodman Brown...as in similiar character or reoccuring themes? thank you so much :)
*February 9, 2009*

**chemistry**

Precipitation Reactions Write a molecular equation for the precipitation reaction that occurs (if any) when the following solutions are mixed. If no reaction occurs, write NO REACTION. Express your answer as a chemical equation. Identify all of the phases in your answer. ...
*February 9, 2009*

**math**

the diameter of a small pizza is 16 centimeters. this is 2 cm more than 2/5 of the diameter of the large pizza so how big is the large pizza
*February 5, 2009*

**Physics**

wait wouldnt you add them because they are both going south
*February 4, 2009*

**Chem Help .plz**

First, You would set up the rate law equation. r=k[OH-]1[CLO2]2 Next, plug in the numbers you have already been given and have figured out r= 230 L2/M2xs [0.175]2 [.0844] Then you should get 5.94x10e-1 as your answer
*February 3, 2009*

**Math**

Simplify the exponential expression. Assume the variables represent nonzero real numbers. (2^-1 x^-5 y^-5)^-2 (2x^-2 y^4)^-2(4x^-2 y^4)^0 ______________________________________ (2x^-5 y^-5)^2 the line by the way means to divide. i have no idea how to solve :( All i know is the...
*January 28, 2009*

**Algebra**

Foam fingers sold for $5. Spirit bracelets for $4. You sold 40 more foam fingers than bracelets and earned $965. Write a system of equations to describe this situation. Solve this system using as least 2 different methods. Explain each method.
*January 26, 2009*

**algebra**

Doesn't the line go on forever, so how could you choose 3 points above it?
*January 26, 2009*

**algebra**

Graph y=2x+1, then choose 3 points above the line. Give the coordinates of each point and tell wether it is greater than, less than or equal to 2x + 1 at each point.
*January 26, 2009*

**English**

Hi i am writing a response paper for "Cathedral" by Raymond Carver. Im not sure but is this a proper thesis statement. In the short story Cathedral, by Raymond Carver, a man refers to Robert as "this blind man." Not only is he categorizing Robert, but he&#...
*January 26, 2009*

**English**

Hi i am writing a response paper for "Cathedral" by Raymond Carver. Im not sure but is this a proper thesis statement. In the short story Cathedral, by Raymond Carver, a man refers to Robert as "this blind man." Not only is he categorizing Robert, but he&#...
*January 26, 2009*

**philosophy**

um this was are first day of philosophy, so i dont know anything you just said bobpursley , i'm just confused in general...im not sure if i talk about that humans are what make up earth, and they have different purposes in life to obtain and stuff like that not sure though...
*January 21, 2009*

**philosophy**

I have to write a 1 page paper "presenting what i believe the world is made of and explain why i believe that to be the case" and he said it doesn't deal with like water and land, so im not sure what he means, any help would be great.
*January 21, 2009*

**college Chemistry**

Ok this is the question... Complete the combustion of butane... CH3CH2CH2CH3 + O2 ====> ____________
*January 21, 2009*

**sceince**

1) which scientist's work did Copernicus contradict? 2) what made it difficult for him to prove his theory? i researched some site but still i dont get it...
*January 11, 2009*

**science**

1) which scientist was later imprisoned for openly supporting the Copernican theory? 2) what did he discover that helped prove that Copernicus was correct?
*January 11, 2009*

**science**

1) which scientist's work did Copernicus contradict? 2) what made it difficult for him to prove his theory?
*January 11, 2009*

**Math**

40 + 40 = 80 so 2 1/2
*January 8, 2009*

**social studies**

There are 32 people.
*January 8, 2009*

**Algebra I**

Stephen is walking from his house to his friend Sharon's house. When he is 12 blocks away, he looks at his watch. He looks again when he is 8 blocks away and finds that 6 minutes have passed. Write 2 ordered pairs for these data in the form (time, blocks). Write a linear ...
*January 7, 2009*

**Algebra**

Write the equation of a line in slope intercept form that contains (3/4, 1/2) and has the same slope as the line described by y + 3x = 6.
*January 7, 2009*

**mathh help pleaseee (: ! <345**

11. It is $20 to start, every hike, you are charged $2 more from the second company. If you divide 20 by 2, 10 will be even and at 11 it will be 2 $ more.
*January 7, 2009*

**chemistry**

its 2/1000
*January 5, 2009*

**Science - gr. 10 physics**

How do you find displacement when given a velocity/time graph?
*January 5, 2009*

**7th grade**

is this like a homework question or are you just wondering?? lol
*January 5, 2009*

**chemistry**

Do you mean 58g/mole?
*January 5, 2009*

**math**

How could knowing that 35/7=5 help you find 42/7? Explain
*January 5, 2009*

**Math-Gr.11 urgent**

hi, i was wondering where you got: 20/2[2a + 19d] from, im in yr 11 but want to start revising a level because i want to get a phd in maths, so i just wanted to know where you got it from, if you could answer this, then thanks
*January 4, 2009*

**biology**

Because it can
*December 17, 2008*

**History**

Ok I know now that the answer is If they left England, they would be Separatists instead of Puritans, and that bothered them. thank you
*December 10, 2008*

**History**

Ok the first one is B? The reason I was confused on it was because that all 3 of them could work. I just didn't know which one was best I guess. And with the other question, I'm still not sure but I think it was fear of Mohawk Revolt?
*December 10, 2008*

**History**

Well I didn't just copy and paste those even if it might look like it. And I only asked 2 questions. Anyway for the first one I am currently thinking that it is probably A or C? Tuxedo's aren't a necessity, yet they are a nice contribution, and the bravery that C ...
*December 10, 2008*

**History**

If someone says that Pilgrims didn't do much for us, what should we say to them? A. Tuxedos were invented because of those black and white outfits the Pilgrims wore. B.That Mayflower Compact they made was the first constitution ever written in North America, and it was ...
*December 10, 2008*

**english**

should i add more information 2 my side....or equal information about both sides thanks
*December 7, 2008*

**english**

thank you, also i have to be able to sympathsize with the other side, but last time i wrote an essay and did that for this class, it sounded like i was for both sides. how do i make it so that i can strongly agree with 1 side, but also can understand where people are coming ...
*December 7, 2008*

**english**

im writing a research essay about the legalization of drugs are there any good websites you have for this topic? Also i have to say which side i take without saying the other side is wrong, and dont know how to make this paper sound too general.
*December 7, 2008*

**accounting**

If i have $550.00 a week.how much is the state deductions in the state of california for one week?
*December 7, 2008*

**Chemistry**

Given: H3PO4(aq) + 3 NaOH(aq) yields 3 H2O(l) + Na3PO4(aq) change in H = -166.5 kJ What is the value for q (heat) if 4.00 g of NaOH reacts with an excess of H3PO4? Please can you explain to me HOW to do this, not just give me an answer? Thanks!
*November 30, 2008*

**Chemistry**

Given: H3PO4(aq) + 3 NaOH(aq) ¨ 3 H2O(l) + Na3PO4(aq) ƒ¢H = -166.5 kJ What is the value for q (heat) if 4.00 g of NaOH reacts with an excess of H3PO4? Please can you explain to me HOW to do this, not just give me an answer? Thanks!
*November 30, 2008*

**Science**

True/False - A generator that doubles the electrical energy from a wall outlet without any additional input of energy will work. - The total amount of energy in the universe is constant. thank you
*November 21, 2008*

**organic**

a peptide contains amino acids Phe,Gly Met,Ala, and Ser. N-terminal analysis yielded the PTH derivative of alanine. Partial hydrolysis of the petapeptide yielded the dipeptides Gly-Ser, Ala-Gly, and Ser-Met. The peptide sequence is what? Ala-Gly-Ser-Phe-Met Ala-Gly-Ser-Met-Phe...
*November 20, 2008*

**organic**

alpha-amino
*November 20, 2008*

**organic**

which is false about naturally occurring a-amino acids? they belong to the D family of chiral compounds related to D-glyceraldehyde all are chiral except for glycine each has a characteristic isoelectric point the ph at which there is no net migration of the amino acid toward ...
*November 20, 2008*

**organic**

what is the best synthesis of 2-heptanol CH3CH2CH2MgBr(2 moles)+formaldehyde in diethyl ether followed by H3O+ CH3CH2CH2MgBr+butanal in diethyl ether followed by H3O+ CH3CH2CH2CH2MgBr+acetone in diethyl ether followed by H3O+ CH3CH2CH2CH2CH2MgBr+ethanal in diethyl ether ...
*November 20, 2008*

**organic**

what is the best synthesis of 4-heptanol (CH3CH2CH2)2CHOH CH3CH2CH2MgBr (2 moles)+formaldehyde (CH2=O) in diethyl ether followed by H3O+ (CH3CH2CH2)2ChMgBr+formaldehyde (CH2=O) in diethyl ether followed by H3O+ CH3CH2CH2MgBr+butanal (CH3CH2CH2CH=O) in diethyl ether followed ...
*November 20, 2008*

**english**

Which of the craftsmen is in charge of the rehearsals?
*November 17, 2008*

**math**

how do you square numbers when your typing?
*November 15, 2008*

**AP Chemistry!!!!**

For our test in a few days, we heard that there was something for pi and sigma bonds overlapping...can someone explain to me the "hybridizaiton" of where they overlap?? I dont understand it.
*November 11, 2008*

**maths**

Find the roots of z^6 + 1 and hence resolve z^6 + 1into read quadratic factors; deduce that cos3x = 4[cos(x) -cos(pi/6)][(cos(x) -cos(pi/2)][(cos(x) -cos(5pi/6)]
*November 10, 2008*

**maths**

Find the roots of z^6 + 1 and hence resolve z^6 + 1into read quadratic factors; deduce that cos3x = 4[cos(x) -cos(pi/6)][(cos(x) -cos(pi/2)][(cos(x) -cos(5pi/6)]
*November 10, 2008*

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