Monday

March 2, 2015

March 2, 2015

Total # Posts: 555

**Chem Uni. Urgent!!!**

Thanks a lot, I obtained 0.85 g as well. Concerning the 0.50g, few crystals were lost during handling.
*February 3, 2015*

**Chem Uni. Urgent!!!**

Have to find theoretical yield of recrystallization of acetanilide from water. 1 gram of crude product used (85% acetanilide, 14% Sodium chloride and 1% charcoal) I got 0.50 grams of purified product. With percent recovery of : (0.50g/1.00g)* 100% = 50%. How do I find the ...
*February 3, 2015*

**Math**

.248... is the volume of the basketball in ft^3. A cubic foot has 1 ft^3 of volume. Subtract .248 from 1 ft, you get .7515 ft^3 Multiply .7515 by 62.4 lb = 46.895 lbs
*January 30, 2015*

**Calculus**

Determine the interval(s) at which f(x) is concave up given that f′′(x)=−x2+x+6. a) (–2, 3) b) (–∞, –2), (3, ∞) c) (–∞, –3), (2, ∞) d) (–2, ∞) e) (–∞, 3)
*January 30, 2015*

**Calculus **

Determine the interval(s) at which f(x) is concave up given that f′′(x)=−x2+x+6. Critical points are: -2 & 3
*January 30, 2015*

**Ionic compounds Scinece**

3. What happens to the change on individual ions when they form ions? 11. Write the names of the two ions in each of the following compounds. (C) Na2O (E) Na3PO4 (G) NH4OH (H) Ca (NO3)2 8. Use the tables of metals, non-metals, and polyatomic ions and the Periodic table to name...
*January 22, 2015*

**Chemistry**

Perchloric acid, HClO4, is a strong acid. What are the pH values of the following solutions: a) 3 M perchloric acid b) 0.1 M perchloric acid c) 0.001234 M perchloric acid d) 10-5 M perchloric acid e) 10-9 M perchloric acid is the pH -log(conc. ?
*January 19, 2015*

**Chemistry**

a solution of HCL is approximately 0.1M and has to be standardized . 1.234g Na2CO3 are dissolved to make 100ml of solution. 20mL of this solution are titrated with the HCL solution, requiring 31.3mL for the second equivalence point. what is the exact concentration of the HCL ...
*January 14, 2015*

**Chemistry**

Draw the pH-titration curve for the following, label x and y axes accordingly. 10 mL of 0.1M H3PO4 with 0.1 M NaOH (Logk values = 2, 7, 12) I understand that the x-axis is mL of H3PO4 added and y-axis is the pH. But the logK values, is that the equiv-points for the tri-protic ...
*January 14, 2015*

**Chemistry (Chromatography)**

Comment on the order of elution of the following solutes in (a) normal phase and (b) reversed phase liquid chromatography. Give reasons why. Solute X - non-polar Solute Y- Polar, a dipole Solute Z - Polar, more polar than solute Y I understand that polarity is the reason of ...
*January 13, 2015*

**Chemistry (Chromatography)**

In elution chromatography (Ion-exchange) outline the order of elution for the following cationic species: Cu2+, Fe3+, Ag+ and Na+? I understand it has to do with polarity, but in which sense i.e does the least polar/most polar species elute first? Thanks
*January 13, 2015*

**Chemistry**

Thanks for the time and help, this was my final working out, don't know if you will receive this, so once again thank you. Step 1: moles Na2CO3 = 1.234g/105.89 g/mol = 0.0116 mol. Step 2: 20mL of Na2CO3 = 0.0116*(20/100) = 0.00232mol/L Step 3: Balanced equation = Na2CO3 + ...
*January 9, 2015*

**Chemistry**

a solution of HCL is approximately 0.1M and has to be standardized . 1.234g Na2CO3 are dissolved to make 100ml of solution. 20mL of this solution are titrated with the HCL solution, requiring 31.3mL for the second equivalence point. what is the exact concentration of the HCL ...
*January 9, 2015*

**PHYSICS**

A 209 kg block is released at height h = 3.3 m as shown. The track is frictionless except for a portion of length 7 m. The block travels down the track, hits a spring of force constant k = 1545 N/m, and compresses it 1.9 m from its equilibrium position before coming to rest ...
*December 10, 2014*

**physics**

A student, late for class, ran up some stairs between landings, which are 11.3 m apart. The student’s mass is 62 kg and it took 6.02 s to do the run. What is the average power that the student generated during the run?
*December 10, 2014*

**Math**

What are the comparisons between the mixed numbers 5.815 and 6.021
*December 10, 2014*

**Calculus**

Find the volume of the solid obtained by rotating the region bounded by the curves: 2x = -y^2 y^2 = -x + 2 y = 0 for y >= 0 about the x-axis. Not sure how to do this one, could anybody help me identify what this looks like and how to identify the outer/inner radius? Thanks
*November 23, 2014*

**Calculus**

Thank you!
*November 23, 2014*

**Calculus**

Scratch that, I received the answer of 11pi/30, I made a calculation error that first time. Is this correct?
*November 23, 2014*

**Calculus**

Find the volume of the solid obtained by rotating the region bounded by the curves: y = x^2 and x = y^2 about the line y = 1. I received the answer pi/30, using the outer radius of (1 - x^2) and the inner radius of (1 - x^(1/2)). Is this correct?
*November 23, 2014*

**Calculus**

This is the question: i[dot]imgur[dot]com/EHneTuB[dot]jpg Am i correct in simply adding 1 + (-3), and equates to (-2) being the answer.
*November 16, 2014*

**Calculus**

If I derive the following, d/dt((a)S(t^2) of (s)^(1/2)ds with S being integral notation (a) being at the bottom of the notation and being a constant (t^2) being at the top of the notation ..I first apply the fundamental theorem of calculus to get.. (t^2)^(1/2) (2t) simplified ...
*November 16, 2014*

**Calculus**

Ah Thanks!
*November 15, 2014*

**Calculus**

Thanks Steve. Does that mean the function is not odd? I thought odd functions are always integrated to = 0 because of their symmetry.
*November 15, 2014*

**Calculus**

This is a definite integral question. Evaluate the following integral: (0)S(a)((x)((a^2 - x^2)^(1/2)))dx with a being a constant and the (0) being at the bottom of the integral notation and (a) at the top. S is the integral notation. I firstly checked whether the function was ...
*November 15, 2014*

**Calculus**

Find f"(x). f(x) = x^3 - (5/x)
*November 11, 2014*

**algebra**

If 3.14*r^2=706.5? what does r=?
*November 11, 2014*

**calculus**

How did you get that Damon? I thought I could only reorder question as e^x/(1/x) and apply hopital rule from there
*November 8, 2014*

**calculus**

This is a question related to L'hopital's rule. lim x -> -infinity of ((x)(e^x)) This thing is weird because I apply l'hopital's rule yet I never receive the correct answer which is supposedly = 0. It just stays in the form [-infinity * -infinity]. Anyone ...
*November 8, 2014*

**Calculus**

This is a question related to L'hopital's rule. lim x -> -infinity of ((x)(e^x)) This thing is weird because I apply l'hopital's rule yet I never receive the correct answer which is supposedly = 0. It just stays in the form [-infinity * -infinity]. Anyone ...
*November 8, 2014*

**Algebra**

You earn $250 per month from your part-time job. You are in a kayaking club that costs $20 per month, and you save at least $100 each month. Write and solve an inequality to find the possible amounts you have left to spend each month.Can someone please help me with this
*October 22, 2014*

**Spanish Check**

I understand completely now! Thank you for your help :)
*October 12, 2014*

**Spanish Check**

Can you tell me if any of my answers are wrong, and if so which/why? Instructions: Choose por or para to fill in the following phrases; 1. Compré las flores __________ mi novia. Compré las flores para mi novia. 2. Hice la tarea __________ la tarde. Hice la tarea ...
*October 12, 2014*

**math**

eva wants to make two pieces of pottery. She needs 3/5 pound of clay for one piece and 7/10 pound of clay for the other piece. She has three bags of clay that weigh 4/5 pound a piece. How many bags of clay will eva need? How many pounds of clay will she have left over?
*October 6, 2014*

**Calculus**

why does the line have to cross (h, ln(h))?
*September 27, 2014*

**Calculus**

ah thank you steve
*September 27, 2014*

**Calculus**

My professor claims that it is solvable because it says that the point (0,0) lieS on a tangent line to the graph y=ln(x) at some point (a,b)
*September 27, 2014*

**Calculus**

Hello, my question is the following: The derivative of f(x) = ln(x) is given by f'(x) = 1/x. Find an equation of the tangent line to the graph y = ln(x) that passes through the point (0,0). So if I go through this using the typical method I use I have the point slope ...
*September 27, 2014*

**math**

A student is attempting to factor a polynomial. Sample mathematical work is shown below. Which statement best applies to the sample mathematical work? Given 3x + 6, the factors of the first term are 3 and x, and the factors of the second term are 1, 2, 3, and 6. Thus, the ...
*September 22, 2014*

**math**

Q: Suppose that for all xE(0,5), f(x) is between 1+x and 3+sin((pi)(x)). Find lim x->2 f(x). Is this question related to the intermediate value theorem? It is confusing me, can anyone help out? I am not certain of what xE(0,5) is defining, is that a set of x values or am I ...
*September 21, 2014*

**Physics**

A steel ball is dropped onto a hard floor from a height of 1.80 m and rebounds to a height of 1.64 m. (Assume that the positive direction is upward.) (a) Calculate its velocity just before it strikes the floor. m/s (b) Calculate its velocity just after it leaves the floor on ...
*September 17, 2014*

**Physics **

A swimmer bounces straight up from a diving board and falls feet first into a pool. She starts with a velocity of 3.00 m/s, and her takeoff point is 1.10 m above the pool. (a) How long are her feet in the air? s (b) What is her highest point above the board? m (c) What is her ...
*September 17, 2014*

**Science**

I think the answer is d output.
*September 16, 2014*

**Analytical CHM **

Rank the following items in order of accuracy when they are used for their intended purpose: Volumetric pipet, beaker, Erlenmeyer flask, MOHR pipet, graduated cylinder, volumetric flask, buret. Explain your asnwer below Most accurate 1. 2. 3. 4. 5. 6. Least accurate 7. ...
*September 5, 2014*

**Grammar**

What is the simple subject and predicate in the sentence: They reach up to 60 inches tall, or 5 feet!
*August 19, 2014*

**auto repair technician**

Is there anyone taking the automobile technician course in penn foster wanting to team up to study together. I'm having trouble with exam #004846
*August 19, 2014*

**life science**

Why this fossils are important discoveries? They have features similar to homo sapiens, and the provide more information about the evolution of humans.
*July 31, 2014*

**Physics**

how much does a 2 lietr bottle of soda pop weigh in pounds? assume that the pop has the density ofg water,namely 1 kg\lietr and that the weight of the bottle itself is negligible?
*July 14, 2014*

**Chem**

A mixture is prepared by adding 28.6 mL of 0.169 M Na3PO4 to 39.7 mL of 0.255 M Ca(NO3)2. What mass of Ca3(PO4)2 will be formed?
*July 1, 2014*

**Chem**

How many grams of water could have its temperature raised from 25 ºC (room temperature) to 100 ºC (the boiling point of water) by the amount of energy released in the formation of 4.0 mol of H2 from hydrogen atoms? The bond energy of H2 is 435 kJ/mol. The specific ...
*July 1, 2014*

**physics, science**

What effect does friction have upon a) ball bounce angle, and b) ‘speed’ of the court? Refer to clay and grass courts to help illustrate your answer. (4 marks) please help!
*June 30, 2014*

**physics**

If a particle has kinetic energy K = 60 MeV when its momentum magnitude p = 100 MeV/c, what is the ratio m/me of its mass to the electron mass?
*May 3, 2014*

**chemistry**

thanks it helped
*March 25, 2014*

**chemistry**

please help! how do i find the molecular mass of C3H5O2 molecular mass of 292 g.
*March 25, 2014*

**Computer science**

Take two inputs from user: N - #items B - budget. There are S items, each with some price value, out of which user needs to select N items in such a way that total bill does not exceed B. The program should print all such combination of N products.
*February 23, 2014*

**Chemistry**

What is the final Celsius temperature if 4.42 L of nitric oxide gas at 35°C is cooled until the volume reaches 1.00 L? Assume the pressure remains constant.
*February 14, 2014*

**Math**

Sierra spent 2/3 of her earnings on clothes and 1/5 on school supplies. She saved the rest. What fraction of her earnings did she save?
*February 11, 2014*

**Social Studies**

so what is the answer
*February 10, 2014*

**Math**

Can you please help with the following: x^2+2x-35=0 I can't remember how to get the different possibilities. Appreciate help, thanks
*February 7, 2014*

**Math**

A dog ate 48 bones. The other dog ate 47 bones. How much bones did both dogs eat?
*February 6, 2014*

**Physics**

Can you please help with the following: x^2+2x-35=0 I can't remember how to get the different possibilities. Appreciate help, thanks
*February 6, 2014*

**Art**

what 2 colors make purple?
*February 5, 2014*

**ecosystems**

Tundra
*January 30, 2014*

**Calculus 1**

On the graph of f(x) = 8*sin(3pi*x), points P and Q are at consecutive lowest and highest points with P occurring before Q. Find the slope of the line which passes through P and Q. Slope = ? I have tried 48/pi and it didn't work
*January 23, 2014*

**science(CHECK ANSWERS)**

how do you know they are right?
*January 10, 2014*

**Math**

Yes but I do not know how to solve your way of the equation.
*January 9, 2014*

**Math**

I also got 1 and 0 but I do not know.
*January 9, 2014*

**Math**

So would the answer be 31?
*January 9, 2014*

**Math**

How can I put that in an equation? would it be n+n+2+n+3=93?
*January 9, 2014*

**Math**

What does it mean by, "The sum of three consecutive odd integers is 93."
*January 9, 2014*

**science(please check answers)**

Hay Matt, number 2 is wrong it's d
*December 20, 2013*

**science plz help right now!!!!**

they are all right Elena. Good Job!
*December 16, 2013*

**science plz help right now!!!!**

1.B 2.D 3.C 4.D 5.C 6.B 7.D 8.B
*December 16, 2013*

**science**

I think it is B but please let me know if I am wrong.
*December 9, 2013*

**Science**

Are all of these questions from Florida Virtual School?
*November 6, 2013*

**calculus**

lim t-> -infinity for sqrt(4t^2-5t-1)/(2t-3) I get infinity or -infinity, but the real answer is -1. How does this occur?
*October 16, 2013*

**calculus**

oops double posted
*October 16, 2013*

**calculus**

The question is: tan(arcsinx)= I know that inverse of sin is 1/sqrt(1-x^2) however this question still confuses me. The outcome is x/sqrt(1-x^2), how did the tan create the additional x ?
*October 16, 2013*

**calculus**

I am still confused. hm.
*October 16, 2013*

**calculus**

f(x) = ln(ln(lnx)) has the domain of (e, infinity). I am not sure how this occurs however. I know in the case of ln x, x must be greater than 0. However where does e come from. e is the base of log in the case of ln, but something is just not clicking for me.
*October 16, 2013*

**calculus**

so basically what i said in the original question is irrelevant.
*October 16, 2013*

**calculus**

oops i think i meant to say that the derivative is 1/sqrt(1-x^2) dang I am tired.
*October 16, 2013*

**calculus**

The question is: tan(arcsinx)= I know that inverse of sin is 1/sqrt(1-x^2) however this question still confuses me. The outcome is x/sqrt(1-x^2), how did the tan create the additional x ?
*October 16, 2013*

**Calculus**

Perfect, thanks.
*October 14, 2013*

**Calculus**

I need step-by-step help for solving the lim x -> 0 for the function sin(x)/(x + tan(x)) I can do simpler ones, but this one throws me off. Thanks.
*October 14, 2013*

**chemistry**

A mixture was formed by adding 4.56g of KCL to water to make 175mL of solution. The density if the solution is 1.12g/mL. Whatis the mass percent and what is the molarity of the potassium chloride solution?
*August 8, 2013*

**math**

Translate the following statement into a numerical expression: 3 times the quantity of H less 233.
*July 30, 2013*

**College Physics**

1. In a region of two-dimensional space, there are three fixed charges: +1 mC at (0, 0), −2 mC at (18 mm, -3 mm), and +3 mC at (-8 mm, 12 mm). What is the net force on the −2-mC charge? Find the magnitude and direction (counterclockwise from the x-axis).
*July 9, 2013*

**Math**

Is 25x squared + 40x +15 a perfect square? And how do you factor it if it is?
*May 24, 2013*

**Math**

Using your answer to the question above, what is the net dollar amount of that rose order?
*May 20, 2013*

**Religion**

The days of Triduum are measured from _ _ _ _ _ _ to _ _ _ _ _ _.
*April 10, 2013*

**7th Grade Language Arts!**

All of them are write bob. Good Job!
*April 3, 2013*

**Physics**

A brick is thrown off a building at a 25 degree angle at 10m/s, it lands 40 meters away, How high is the building?
*March 26, 2013*

**chemistry**

85.0 of is initially at room temperature (22.0). A chilled steel rod at 2.0 is placed in the water. If the final temperature of the system is 21.2, what is the mass of the steel bar? Specific heat of water = 4.18 Specific heat of steel = 0.452 My answer was 32.752. I rounded ...
*March 26, 2013*

**chemistry**

85.0 of is initially at room temperature (22.0). A chilled steel rod at 2.0 is placed in the water. If the final temperature of the system is 21.2, what is the mass of the steel bar? Specific heat of water = 4.18 Specific heat of steel = 0.452 My answer was 32.752. I rounded ...
*March 26, 2013*

**math**

lol
*March 17, 2013*

**math**

Is there a way to prove this in upwards of 5 steps? Apparently there is?? Prove. 2^n + 2^n = 2^(n+1) I posted this before however apparently I need something more indepth in terms of the # of steps.
*March 17, 2013*

**math**

ok thanks
*March 17, 2013*

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