Sunday

July 5, 2015

July 5, 2015

Total # Posts: 832

**chemistry f/u**

Thank you Mr. bobpursley. I am still unclear on a few things. massethanol*Ceth(Tf-7.7)+masswater*Cwater*(Tf-27.1)=0 solve for Tf 17.75g ethanol x(Tf-7.7)+31.6g water x (Tf-27.1)=0 This is the algebra that I do not know how to derive to move to the next step. Do I add it all to...
*September 4, 2011*

**Chemistry**

New problem. Any assistance is greatly appreciated. 22.5 ml of ethanol (density=0.789 g/ml) initially at 7.7 deg. C is mixed with 31.6 ml of water (density=1.0 g/ml) initially at 27.1 deg. C in an insulated beaker. Assuming that no heat is lost, what is the final temperature ...
*September 4, 2011*

**Chemistry**

New problem. Any assistance is greatly appreciated. 22.5 ml of ethanol (density=0.789 g/ml) initially at 7.7 deg. C is mixed with 31.6 ml of water (density=1.0 g/ml) initially at 27.1 deg. C in an insulated beaker. Assuming that no heat is lost, what is the final temperature ...
*September 4, 2011*

**Dr. Bob**

Thank you kind sir for guiding my work on the last question. You gave me the means to answer the question correctly without giving me the answer. Your expertise is greatly appreciated. If you tutor online, I would gladly pay for your guidance if you are interested
*September 4, 2011*

**Chemistry**

Thank you very much for your assistance preemptively. My question has to do with law of conservation of mass. A 50g sample of iron reacts with 21g of oxygen to from how many grams of iron oxide? Is the answer maybe 71g or 29g. This is stumping me.
*September 3, 2011*

**chemistry**

This has to do with law of conservation of mass I believe but it stumps me. 50g or iron reacts with 21g of oxygen to form how many gram of iron oxide? Is the answer 71g or 29g
*September 3, 2011*

**Pre-Calc**

Find [4(cos115+isin115)]^6
*July 25, 2011*

**calculus**

Why did the 2ðx^2+108/x^2 become 2ðx-108/x^2
*July 18, 2011*

**calculus**

A large soup can is to be designed so that the can will hold 54pi cubic inches of soup. The radius of the can is "x" inches and the height of the can is "h" inches. Find the values for the radius and the height such that the amount of metal needed is as ...
*July 18, 2011*

**MATH**

1) During the two months of the summer holiday, you find a summer job that pays $160 per week with a $10 a week raise. How much money will be made by the end of the summer? 2 Your grandmother offers you $1 on the first day of March break and offers to double it each day of the...
*July 8, 2011*

**derivative **

Find the derivative. 11) f(t)=(1)/(sqrt(8t-3)) 12) g(t)= ((4t-3)^2)/ ((5t+1)^4) Thanks.
*June 15, 2011*

**calculus**

18) The demand equation is x + 1/6p - 10+0. Compute the elasticity of demand and determine whether the demand is elastic, unitary, or inelastic at p=50. a) 5; elastic b) 1/9; inelastic c) 7/6; elastic d) 6; elastic I choose answer A. Is that correct?
*June 15, 2011*

**maths**

The mean weight (1.0042kg) of the contents of samples of 30 bags of sugar has standard error 0.008kg. Choose the option that is closest to the probability, to three decimal places, that the mean weight of the contents of samples of 30 bags of sugar will be 1kg or more. Options...
*June 13, 2011*

**maths**

The mean weight (1.0042kg) of the contents of samples of 30 bags of sugar has standard error 0.008kg. Choose the option that is closest to the probability, to three decimal places, that the mean weight of the contents of samples of 30 bags of sugar will be 1kg or more. Options...
*June 12, 2011*

**maths**

The mean weight (1.0042kg) of the contents of samples of 30 bags of sugar has standard error 0.008kg. Choose the option that is closest to the probability, to three decimal places, that the mean weight of the contents of samples of 30 bags of sugar will be 1kg or more. Options...
*June 11, 2011*

**physics**

i need a mathematical relationship between density and height
*June 9, 2011*

**Algebra 2 **

Find the distance between the points (12, 8) and (4, 2). 100 units 14 units 10 units –10 units Find the midpoint of the points (3, 1) and (7, –5). (1, 6) (2, 1) (2, –3) (5, –2) Find the vertex and focus of the parabola whose equation is 4y = x2 + 4. V(0, 4...
*June 4, 2011*

**Algebra 2 **

1. Find the midpoint and the distance between the points (8,–6) and (13, 4). 1. (4, –3), 10 units 2. 3. 4. (10, –1), 9 units 2. Find the vertex and the focus of the parabola with the equation 4y = x2 – 12x + 52. 1. V(6, 4), F(6, 5) 2. V(6, 4), F(7, 4) 3. V(...
*June 4, 2011*

**MathHelp**

The fare for riding in a taxi is a $3 fixed charge and $0.80 per mile. The fare for a ride of d miles is $6.75. Write an equation that could be used to find d.
*May 26, 2011*

**Algebra**

Par Manufacturing manufactures steel rods. Suppose the rods ordered by a customer are manufactured to a specification of 0.5 in. and are acceptable only if they are within the tolerance limits of 0.49 in. and 0.51 in. Letting x denote the diameter of a rod, write an inequality...
*May 26, 2011*

**math**

well for the first one i'm pretty sure it is a parabola, and i'm confused on how you would find the vertex focus and directrix
*May 19, 2011*

**math**

how would you solve these equations? y^2+2y-2x+5=0 and (x^2/16)-(y+1)^2/(25)=1 thank you!
*May 19, 2011*

**science**

Whats a good reason for dissecting a heart and what would be the purpose?
*May 12, 2011*

**chemistry**

given 14g silver oxide, how much silver can be made?
*May 9, 2011*

**stats**

use technology to find the P-value for a two tailed test with n=28 and a test statistic t=2.032 P-value =???? Help please! i dont understand this
*May 8, 2011*

**math**

Thanks. So no matter what the times I have to subtract the starting time from the ending time - right?
*May 5, 2011*

**math**

if a game is started at 7:48am and finishes at 10:58am ... how do I figure how many hours and minutes it took to finish the game?
*May 5, 2011*

**Statistics**

A certian company enjoyed 3.5% profits in year 1 over its revenue in Year 0. In Year 2, it enjoyed 5.75% profits over Year 1. In Year 3, it posted 1.25% profits over Year 2. What single, constant profit over this period of years would have produced the same profit? The teacher...
*May 3, 2011*

**physics**

A particular guitar string is supposed to vibrate at 192 Hz, but it is measured to actually vibrate at 212 Hz. By what percent should the tension in the string be changed to get the frequency to the correct value?
*May 1, 2011*

**Chemistry HELP!!**

A sample of nicotine weighing 0.3204 g was vaporized in a flask with a volume of 487 mL. This sample exrted pressure of 74.3 mm Hg at 20 degrees C. What is the molar mass of nicotine? I know this has to do with N=P*V/R*T. and 1 atm=760 mm Hg. Please help and show work. ...
*April 28, 2011*

**Chemistry**

so then would i take: .284 L/44 g/mol =.006 then .006*100 g/mol =.645 then take .645/1.506 = .429 ---->.429 * 100 = 42.9% is this how i would get the answer?
*April 28, 2011*

**Chemistry**

a sample of limestone and other solid materials is heated and the limestone decomposes to give calcium oxide and carbon dioxide: CaCO3 ----> CaO + CO2 a 1.506 g sample of limestone containing material produces 284 mL of CO2 at STP. what is the mass percent os CaCO3 in the ...
*April 28, 2011*

**Chemistry**

A sample of nicotine weighing 0.3204 g was vaporized in a flask with a volume of 487 mL. This sample exrted pressure of 74.3 mm Hg at 20 degrees C. What is the molar mass of nicotine? I know this has to do with N=P*V/R*T. and 1 atm=760 mm Hg. Please help and show work. ...
*April 28, 2011*

**Chemistry DrBob**

I don't understand how you get the answer. I really don't understand any of this, how do I set it up with the numbers? once i get how to do this, then i feel i will understand how to set these up from here on out. so if you could, show all your work, thanks (A). A ...
*April 27, 2011*

**Chemistry**

(A). A reaction with a known q is performed in a bomb calorimeter and is found that 10.0 kj of heat is required to raise the temperature of the calorimeter by 2.15 degrees C. calculate the heat capacity of the calorimeter. (B). When 1.00 g of C2H6(g) is burned in the bomb ...
*April 27, 2011*

**chemistry**

a reaction witha known q is performed in a bomb calorimeter and is found that 10.0 kj of heat is required to raise the temperature of the calorimeter by 2.15 degrees C. calculate the heat capacity of the calorimeter.
*April 27, 2011*

**chemistry**

a reaction witha known q is performed in a bomb calorimeter and is found that 10.0 kj of heat is required to raise the temperature of the calorimeter by 2.15 degrees C. calculate the heat capacity of the calorimeter.
*April 27, 2011*

**math**

what would be the length of a shadow cast by a 50 foot high building?
*April 26, 2011*

**Physics**

Looks like your screwed
*April 14, 2011*

**Algebra 1**

How do you graph the function: y = 6x(squared) - 12x + 1 Then, how would you find the Axis of Symmetry and the Vertex? Any help is greatly appreciated
*April 14, 2011*

**calculus**

Please help. I need ( with details) how to differentiate with the chain rule f(x)=(x^2-6x+23)^3/2. I need to
*April 10, 2011*

**Com155**

So sorry. I am not good at english class thats why I am asking for help.
*April 4, 2011*

**Com155**

Sorry I wrote it wrong. The list is adjectives. I am having trouble finding the other adverb.
*April 4, 2011*

**Com155**

I think the adverbs are live, teenage, family, becoming, providing and world's. I cant figure out the other adjective.
*April 4, 2011*

**Com155**

Are they family and accidentally
*April 4, 2011*

**Com155**

Could you please help me locate the adjectives and adverbs in the below paragraph? ”Blending state of the art animation with live action, Hop is a comedy about E.B., the teenage son of the Easter Bunny. On the eve of taking over the family business, E.B. leaves for ...
*April 4, 2011*

**Chemistry**

508 cm fly
*March 28, 2011*

**MATH**

A yard stick/ruler would probably be a good choice. Measuring tape perhaps.
*March 27, 2011*

**Physics**

A particle with a mass of 2.0×10−5 kg and a charge of +2.0 microC is released in a (parallel plate) uniform horizontal electric field of 13 N/C. If the plates are 5.6 cm on each side, how much charge is on each? (in pC) From what I have so far, the formula E=(4piKQ...
*March 27, 2011*

**physics**

I think you forgot to include the actual question part...
*March 27, 2011*

**Physics**

I whole-heartedly agree!
*March 26, 2011*

**Physics**

Two charges, -2.0 micro C and -6.0 micro C, are located at (-0.65 m, 0) and (0.65 m, 0), respectively. There is a point on the x-axis between the two charges where the electric field is zero. Find the location of the point where the electric field is zero.
*March 26, 2011*

**chemistry**

Name the following compounds (with absolute configurations) and are they enantiomers, diastereomers or structure isomers or no relation at all? img34.imageshack.us/i/namethese.jpg/ i think they are disteromers and their names are 1] 1S, 2S - (2-bromo - 3,4 - dimethyl pentane) ...
*March 17, 2011*

**chemistry**

Write down the reaction between 1-pentyne and 2 molar HBr should it be 2 br or 4 br? img718.imageshack.us/i/triple2.jpg/
*March 14, 2011*

**chemistry**

i posted this already but i got the answer for someone elses question. the pka of acetone is CH3COCH3 is 19.3 which of these bases is strong enough to deprotonate acetone? a)KOH (pka of H20 = 15.7) b)Na+ -C(triplebond)CH (pka of C2H2 = 25) c)NaHCO3 (pka of H2CO3 = 6.4) d)...
*March 14, 2011*

**chemistry**

i posted this already but i got the answer for someone elses question. the pka of acetone is CH3COCH3 is 19.3 which of these bases is strong enough to deprotonate acetone? a)KOH (pka of H20 = 15.7) b)Na+ -C(triplebond)CH (pka of C2H2 = 25) c)NaHCO3 (pka of H2CO3 = 6.4) d)...
*March 12, 2011*

**Chemistry**

the pka of acetone is CH3COCH3 is 19.3 which of these bases is strong enough to deprotonate acetone? a)KOH (pka of H20 = 15.7) b)Na+ -C(triplebond)CH (pka of C2H2 = 25) c)NaHCO3 (pka of H2CO3 = 6.4) d)NaOCH3 pka of CH3OH = 15.6) i know the answer is b but why is it b? is it ...
*March 12, 2011*

**AP Chemistry**

There is an unknown amount of unlabelled monoprotic acid in an unknown amount of water titrated with a sample with a solution of NaOH of unknown molarity. After adding 10.0 mL of NaOH, the pH=5.0. The equivalence point is 32.22 mL of NaOH. What is the Ka? I have been looking ...
*March 8, 2011*

**calculus**

Determine the values of a and b for the function f (x) = ax^3 + bx^2 + 3x - 2 given that f (2) = 10 and f ′(-1) = 14. Please help, Thanks!
*March 1, 2011*

**SQL**

Explain why the following command would create an error, and what changes could be made to fix the error. SELECT V_CODE, SUM(P_QOH) FROM PRODUCT;
*March 1, 2011*

**chemistry**

you're right! sorry i guess im just tired from over studying that i saw the wrong letter!
*February 28, 2011*

**chemistry**

Degree of unsaturation why is it 5? C20H32CIN do i ignore the second C? because i did 21(2)+2=44 44-32+1-1 / 2 = 6 but i get it right with 20(2)+2=42 42-32-1+1 / 2 = 5 do i always ignore extra C's?
*February 28, 2011*

**french**

please unscramble this word.. the word is eeienhtocasr
*February 24, 2011*

**french**

thanks
*February 24, 2011*

**french**

can you unscamble eeienhtocasr
*February 24, 2011*

**math**

two thirds of 9 is 6 and one third of 18 is 6 if you draw a gragh of 9 divide it into three sections.each section is a third,two of those sections equal two thirds which is 6.now a graph of 18 divided into 3 sections each section is 6.each section represents one third. 6 is ...
*February 24, 2011*

**chemistry**

Write the major products with the correct regiochemistry and stereochemistry for 1- ethylcyclohexene and the following reagents: a) NBS, H2O, DMSO if someone could atleast direct me to a site or anything that would be great.
*February 22, 2011*

**Physics**

In the figure below, two blocks are connected over a pulley. The mass of block A is 12 kg, and the coefficient of kinetic friction between A and the incline is 0.22. Angle θ is 30°. Block A slides down the incline at constant speed. What is the mass of block B?
*February 21, 2011*

**calculus**

Consider the graph of y2 = x(4 − x)2 (see figure). Find the volumes of the solids that are generated when the loop of this graph is revolved about each of the following
*February 21, 2011*

**chemistry**

Mechanism for the reaction between 3-methyl-2-pentene and HCl. is this right? %img836.imageshack.us/i/questionk%.jpg/% * delete the percentages for the link to work, its the only way i could post a link
*February 19, 2011*

**chemistry**

Write down the correct mechanism for the reaction between 3-methyl-2-pentene and HCL?
*February 18, 2011*

**Econ**

Consider the following consumption function. C = 200 + .75(DPI), Where C is consumption, autonomous spending is 200, the MPC is .75, and DPI is disposable personal income. Using the Graph below, graph the Consumption Function. C 100 0 = Income On the Graph, label the point ...
*February 18, 2011*

**physics**

jkjkjkjkjkjkjkjkjkjkjk
*February 18, 2011*

**chemistry**

thanks, but didnt really find the answer to my question...
*February 17, 2011*

**chemistry**

Im doing my lab report about steam distillation? and its asking me how i can tell if the two compounds i steam distilled are pure. but im not sure how to tell? i mean is the volatile or the nonvolatile compound the pure compound? or maybe the boiling point is what tells me if ...
*February 17, 2011*

**chemistry**

How can you tell if two compounds that you steam distilled are pure?
*February 17, 2011*

**Business**

what are the atributes of tomorrow's leaders according to linda hill?
*February 17, 2011*

**Random Question**

thanks alot!
*February 12, 2011*

**Random Question**

ok Thanks.
*February 12, 2011*

**Random Question**

Does anyone know of any jobs hiring now???
*February 12, 2011*

**Algebra 1**

How do you solve this algebraic equation using graphing? y = 3x - 1 y = -x + 1
*February 12, 2011*

**Magnetism**

Great, thanks a lot!
*February 10, 2011*

**Magnetism**

This is a circular coil and indeed the open area is 227 cm No not perpendicular but parallel from the coil (measured 30 cm away from above the coil). My Gauss meter is not sensitive enough to pick up the signal at this distance. Can you somewhat elaborate more on the various ...
*February 10, 2011*

**Magnetism**

I need to calculate the magnetic field strength at 30 cm distance of a coil with a diameter of 17 cm. Directly at the coil surface I measure 100 Gauss. Please advise.
*February 10, 2011*

**math**

Find the area of an equilateral triangle (regular 3-gon) with the given measurement. 6-inch side. A = sq. in.
*February 1, 2011*

**Chemistry**

How to know overall charge of molecule? see question # 12 here, why is it -1? how do you know? itech.pjc.edu/tgrow/2210/chm2210ps4sol.pdf
*January 29, 2011*

**chemistry**

Any easy way to remember the names and structures of functional groups? lol a lot to ask i know.?
*January 28, 2011*

**math**

Find the area of an equilateral triangle (regular 3-gon) with the given measurement. 9-inch perimeter A = sq. in.
*January 28, 2011*

**Physics**

A toy car coasts uphill at 2.34 m/s. It accelerates at -.34 m/s squared. How long will it take the car to stop.What equation would I use.
*January 28, 2011*

**CHEM**

Ok, thank you.
*January 25, 2011*

**CHEM**

Are these cations, how do i know? BF3, BH3, AlCl3, FeCl3 how do i recognize a cation?
*January 25, 2011*

**chemistry**

can fractional distillation be used to determine purity of a compound?
*January 25, 2011*

**chemistry**

Calculate the formal charge on each non-hydrogen atom in eachof the following molecules (show your work) i know the answer but can someone tell me how to get to the answer? 1) H2C=N=N(2 dots on top and on side) 2. H2C-N(3 bonds)C(2dots)
*January 18, 2011*

**chemistry**

Calculate the formla charge on each non-hydrogen atom in eachof the following molecules (show your work)
*January 18, 2011*

**chemistry**

hey
*January 18, 2011*

**chemistry**

okay, that helps a lot thanks!
*January 18, 2011*

**chemistry**

im not sure how to answer the questions.
*January 18, 2011*

**chemistry**

discuss if and when melting points can be used to determine the purity of organic and inorganic compounds and if and when melting points can be used to identify organic and inorganic compounds.
*January 18, 2011*

**4th grade**

8 and 3/4
*December 15, 2010*

**chem class**

Our teacher told us we had to do problems on our final on Delta G and S...? all he said is we'd have to plug in numbers from a list and solve. but im very confused. but the numbers he gave in the example are different from my book, is there soemthing we have to do to the ...
*December 13, 2010*