Saturday

March 28, 2015

March 28, 2015

Total # Posts: 404

**Chemistry **

What is the Ka of the amino acid serine if it is 34.5% dissociated at pH- 9.46?
*May 4, 2013*

**Chemistry**

ok thank you!
*April 30, 2013*

**Chemistry**

dG=? . how do I start this problem? Do I use dG= -RT*ln*K? dG=-(0.008314 kj/k*mol) (61+ 273.15) ln (29.24)?? I tried this and it is wrong.
*April 30, 2013*

**Chemistry**

DrBob222, I don't know how to solve this problem either. And yes, this is the question for this problem. I even double check it. Please help. Chloroform (CHCL3) has a normal boiling point of 61 'C and an enthalpy of vaporization of 29.24 kJ/mol. What is the value of ...
*April 30, 2013*

**Chemistry**

Chloroform (CHCL3) has a normal boiling point of 61 'C and an enthalpy of vaporization of 29.24 kJ/mol. What is the value of delta Gvap (in kJ) at 61'C for chloroform?
*April 30, 2013*

**Chemistry**

I realized where I made a mistake for this problem. This time, I got this one right. Thank you so much!
*April 30, 2013*

**Chemistry**

The following thermodynamic data was obtained for an unknown compound. Delta Hvap = 31.3 kj/mol and Delta S Vap= 79.7 kj/mol .Calculate the normal boiling point of this compound in Celcius.. Thank you! Chemistry - DrBob222, Tuesday, April 30, 2013 at 12:31am dG = dHvap - ...
*April 30, 2013*

**Chemistry**

At 20 degree celsius, Ka for an unknown monoprotic weak acid is 0.00088. Calculate the Delta G (in kJ/mol) for the reaction of this unknown acid with water. HA(aq) + H2O(l) <--> H3O+(aq) + A-(aq)
*April 30, 2013*

**chemistry**

Calculate the enthalpy of fusion of naphthalene (C10H8) given that its melting point is 128 Celsius and its entropy of fusion is 47.7 J (k*mol) .
*April 29, 2013*

**chemistry**

Given that for the vaporization of benzene Hvap= 30.7 kj/mol and Svap= 87.0 J(K * mol) , calculate Delta G (in kJ/mol) for the vaporization of benzene at 13 Celcius.
*April 29, 2013*

**Chemistry**

The following thermodynamic data was obtained for an unknown compound. Delta Hvap = 31.3 kj/mol and Delta S Vap= 79.7 kj/mol .Calculate the normal boiling point of this compound in Celcius.. Thank you!
*April 29, 2013*

**Chemistry**

Calculate the molar solubility of MgCO3 in a solution that already contains 1.7×10−3 M sodium carbonate. MgCO3 Ksp = 6.82 x 10-6 IMPORTANT NOTE: You must use the quadratic equation to solve this problem. (DrBob222- thank you so much for all your help!)
*April 26, 2013*

**Chemistry**

how did you get (that's 0.17M x 1/2 = 0.085M)
*April 24, 2013*

**Chemistry**

What is the ph at the equivalence point for a titration of 250 mL of 0.17M piperidine with 0.17 M nitric acid. (piperidine: Kb = 1.3 x 10-3)
*April 23, 2013*

**Chemistry**

Consider the titration of 41.2ml of 0.230 M HF with 0.220 M NaOH . Calculate the ph after the addition of 11.9ml of sodium hydroxide.(HF: Ka = 3.50 x 10-4) Please, I need step by step on on how to solve this type of problem. Thank you very much!
*April 23, 2013*

**Chemistry**

A 17.6ml sample of a monoprotic acid is titrated with 0.212M NaOH. If 69.2ml of base is required to reach the equivalence point, what is the concentration of the acid?
*April 19, 2013*

**social studies**

what wiped out most of the indigenous population of australia
*April 8, 2013*

**Physics**

Sammy Sosa
*March 19, 2013*

**Math**

There are 16 cubic boxes of erasers in a case. What are all the possible dimensions for a case of erasers ? please help need in 30 minutes or less so confused help please thanks
*March 10, 2013*

**Chemistry**

what is the freezing point of 16.7g of LiCl in 136g of water, assuming complete dissociation for water kf= -1.86/mol
*February 26, 2013*

**Chemistry**

what is the freezing point of 16.7g of LiCl in 136g of water, assuming complete dissociation for water kf= -1.86/mol
*February 26, 2013*

**Chemistry**

what is the freezing point of 16.7g of LiCl in 136g of water, assuming complete dissociation for water kf= -1.86/mol
*February 26, 2013*

**Chemistry**

what is the freezing point of 16.7g of LiCl in 136g of water, assuming complete dissociation for water kf= -1.86/mol
*February 26, 2013*

**CSU**

what is the freezing point of 16.7g of LiCl in 136g of water, assuming complete dissociation for water kf= -1.86/mol
*February 26, 2013*

**Math-grade 4**

thank you ms. sue.my mom said the same thing.
*February 4, 2013*

**Math-grade 4**

I have 12 with a remainder of 3. my teacher wants us to round and estimate. please help! do I round it to 7 divided by 70?
*February 4, 2013*

**Math-grade 4**

what is the estimated quotient of 6 divided into 75?
*February 4, 2013*

**math**

I don't know
*January 28, 2013*

**math **

katie is 4 years younger than sylvia. let k represent katie's age and let s represent slyvia's age.
*January 22, 2013*

**algebra**

It's m-3
*January 9, 2013*

**MATHS**

Is there any reason why f(g)=g^2+3 why do we replace the x with g? Sorry steve im trying my hardest to understand this
*December 19, 2012*

**MATHS**

Thank you steve It says i need to find f(g), i got a different result for some reason help please! And also in the second part, how did you get g^-1 = (x-1)/2 Thank you steve x
*December 19, 2012*

**MATHS**

Critical help please. Level 3 maths algebraic methods is really hard. Q) Two functions f and g are defined by f:x (arrow) x^2 + 3 g:x (arrow) 2x+1 Find a) the function fg b) solve the equation f(x)=12g^-1(x) I need to show my working out, please help someone
*December 19, 2012*

**Algebra 1**

Which one is it? A or D?
*December 18, 2012*

**Maths**

If tom got 200 euro for his birthday. He spent 1.0 how much did he spend?
*December 6, 2012*

**English**

What type of poem is this ? We found his flag one bitter morning And knew our hopes had come to woe. We had come pursuing glory But ended freezing in the snow. 1. The stanza of the poem offers an example of (1 point) slant rhyme. end rhyme. perfect rhyme. * internal rhyme. I ...
*December 5, 2012*

**Math**

Mrs. Yale wrote a number between 35 and 48 on her board. The sum of the digits is 7. What number did Mrs. Yale write on her board?
*October 23, 2012*

**health**

is it A??
*October 5, 2012*

**English**

Yes, I know what similes and metaphors are. My question is where are their examples of similes and metaphors in the story?
*September 18, 2012*

**English**

In the story The Necklace written by Guy de Maupassant what are the examples of similes and metaphors?
*September 18, 2012*

**ashworth**

i go to the same school for homeschooling and i need help with the same question
*July 8, 2012*

**Business law**

The state of Confusion enacted a statute requiring all trucks and towing trailers that use its highways to use a B-type truck hitch that is presently being manufactured by only one manufacturer, which is located in Confusion. The result of this statute is that any trucker who...
*June 27, 2012*

**chemistry **

a 3.00g sample of baking soda is heated and decomposes according to the reaction below. Calculate the theoretical yield in grams for each of the three products Na2Co3. H2O, CO2
*June 17, 2012*

**chemistry**

From the following Information, calculate the standard change of enthalpy for the combustion of coal. SHOW WORK AND BALANCED REACTION!!! Compound DeltaHf (kj/mol) Coal 0.0 Carbon dioxide -393.5 Water (l) -285.9 Oxygen 0.0
*June 12, 2012*

**chemistry**

From the following Information, calculate the standard change of enthalpy for the combustion of coal. SHOW WORK AND BALANCED REACTION!!! Compound DeltaHf (kj/mol) Coal 0.0 Carbon dioxide -393.5 Water (l) -285.9 Oxygen 0.0
*June 12, 2012*

**chemistry**

What is the molar solubility of Sr3(AsO4)2 and the concentration of Sr^+2 and AsO4^-3 in a saturated solution at 25C? the Ksp is 1.3 E -18. Show the balanced reaction.
*June 10, 2012*

**Math**

How would I prove: 2^n + 2^n = 2^(n+1) The question asks for correct formatting in giving proof however I don't recall learning this before. Any help would be appreciated!
*May 28, 2012*

**Math**

12. A particular power boat travelling at V0 km/h when its power is turned off it will have its speed V given by V(t) = V0 x 10^-0.18t where t is the time in seconds since the engine was turned off. If this boat was travelling at 50k/h before powering down, construct a table ...
*May 28, 2012*

**math**

THANK YOU MY GOD YOU SAVED MY LIFE
*March 21, 2012*

**Chemistry**

If 150.0 grams of iron at 95.0 degrees Celcius, is placed in an insulated container containing 500.0 grams of water at 25.0 degrees Celcius, and both are allowed to come to the same temperature, what will that temperature be? The specific heat of water is 4.18 J/g degrees ...
*February 22, 2012*

**Geometry**

i have the same question in my class too so thank you
*February 14, 2012*

**Physics **

A ball is tossed from an upper-story window of a building. The ball is given an initial velocity of 8.15 m/s at an angle of 18.5o below the horizontal. It strikes the ground 3.30 s later. How far horizontally from the base of the building does the ball strike the ground? What ...
*February 7, 2012*

**physics**

Describe in detail an experiment to find out the half life of a radioactive material
*January 31, 2012*

**physics science**

Please can you help as I am stuck, Describe ib detail, how you would carry out an investigation to measure the density of a block of aluminium? Thankyou
*January 31, 2012*

**physics science**

Sorry can someone please so me how to do this thanks
*January 31, 2012*

**physics science**

Sorry I don't understand this I have do decribe in detail the investigation could you please give me some pointers on how to start Thanks again
*January 31, 2012*

**physics science**

Please can you help as I am stuck, Describe ib detail, how you would carry out an investigation to measure the density of a block of aluminium? Thankyou
*January 31, 2012*

**Math**

When you do a free throw, you get 2 tries 42/60=.7=7/10=70% probability(make) 10/10-7/10=3/10=30% probability (miss) 0 points= 3/10=30% 1 point= 7/10•3/10=21/100=21% 2 points= 7/10•7/10=49/100=49% To make sure it's in the range of 100 as the whole number add 3/10...
*December 14, 2011*

**Calc**

We are working on finding the intervals of convergence of power series in class. Why do we not have to test for the convergence of the endpoints for geometric series? They always seem to diverge. Is this a set rule when working with the geometric series for this type of problem?
*December 1, 2011*

**irish**

thank you they were very helpful and thank's again
*November 30, 2011*

**irish**

im sorry for being cheeky i just find this hard
*November 30, 2011*

**irish**

its not an assignment and i was only asking if anyone understood this im sorry ok
*November 30, 2011*

**irish**

25 sentences on how you WILL SPEND! a day either at the weekend or tomorrow, a school day, or any piece of writing in the future tense. in irish can you help with a couple of them please!
*November 30, 2011*

**health and social care**

can you tell me about the nature vs nurture debate please thankyou
*November 16, 2011*

**Maths**

In the spring, 80% of the sheep in a flock of sheep had lambs. of those sheep with lambs, 30% had one lamb, 40% had two lambs and the rest had 3 lambs. a total of 240 lambs were born. how many sheep are in the flock? you must show your working.
*November 7, 2011*

**science**

please help
*November 6, 2011*

**science**

preparation of copper sulphate crystals excess copper oxide is needed above a)how do you know the solid is in excess? b)how do you remove the excess? c)what colour is the solution? d)give the next to steps to make crystals?
*November 6, 2011*

**MATHS**

the 50p is a 50p piece it says in the book it is less than 50p (money)
*November 5, 2011*

**MATHS**

please help
*November 5, 2011*

**MATHS**

matt and ruba each have one coin. The total amount of money is less than 50p. work out the probability that exactly one of the coins is a 10p piece. assume that all possible coins are equally likely.
*November 5, 2011*

**maths**

please help as soon as possible
*November 4, 2011*

**maths**

matt and ruba each have one coin. The total amount of money is less than 50p. work out the probability that exactly one of the coins is a 10p piece. assume that all possible coins are equally likely. please can you explain i have to know how to do this
*November 4, 2011*

**CHEMISTRY**

Thank you
*November 2, 2011*

**CHEMISTRY**

thank you so is AL2O3 3 elements Ca(HCO3)2 4 elements
*November 2, 2011*

**CHEMISTRY**

please help
*November 2, 2011*

**CHEMISTRY**

how many elements in (NH4)2SO4
*November 2, 2011*

**chemistry ASAP**

name the following: H2SeO3 H2TeO2 PO3^3- HCLO4 Please explain how to find the names !!!!!
*October 31, 2011*

**Physics**

The conducting rod ab shown below makes frictionless contact with metal rails ca and db. The apparatus is in a uniform magnetic field of 0.855 T, perpendicular to the plane of the figure. The length L of the rod is 25 cm. (a) Find the magnitude of the emf induced in the rod ...
*October 19, 2011*

**math**

what is the total price of a sweatshirt that is priced at $48 and taxed at 6.5%?
*October 11, 2011*

**6th**

what is the sum of 3142,6328, and 4743 to the nearest thousand?
*October 6, 2011*

**maths**

a car travels at a speed of 35mph how long would it take a car to travel 7miles
*October 3, 2011*

**physcis!**

A car accelerates from rest at 4.9 m/s2. How much time does it need to attain a speed of 6 m/s?
*September 18, 2011*

**physics! please help!**

A car accelerates from rest at 4.9 m/s2. How much time does it need to attain a speed of 6 m/s?
*September 18, 2011*

**Physics**

Two ants race across a table 65 cm long. One travels at 5.76 cm/s and the other at 3.99999 cm/s. When the first one crosses the finish line, how far behind is the second one?
*September 18, 2011*

**Calculus**

The graph A(x) has points (-3,0), (0,-2), (1,0) and (2,3). If C(x) is defined by C(x)=A(2x+3), then what is the domain and range of C and how would the graph of C(x) look like? Also, is there any way to find what the actual equation of A(x) is with the points listed above? ...
*September 6, 2011*

**Physics**

An object, that is 3.25 mm high is placed 16 cm in front of a lens. The image produced by this lens appears 6.0 cm behind the object, as the figure shows. (a) What is the focal length of this lens and what type of lens is it? (b) What is the height of the image? Is it real or ...
*July 27, 2011*

**Physics**

An object 0.600 cm tall is placed 16.5 cm to the left of the vertex of a concave mirror having a radius of curvature of 22.0 cm. (a) Draw a principle-ray diagram showing the formation of the image. (b) Calculate the position, size, orientation (erect or inverted), and nature (...
*July 27, 2011*

**Physics**

A speedboat, starting from rest, moves along a straight line away from the dock. The boat has a constant acceleration of +3.00 m/s2. A siren on the dock is producing a 755 Hz tone. Assuming that the air temperature is 20.0oC, what is the frequency of the sound heard by a ...
*July 27, 2011*

**sciencs**

what is denser, 1 grams of gold or 1 kilograms of copper? why?
*July 25, 2011*

**physics**

additional information:the distance between wire 1 and wire is 25 cm and the distance between the wire 2 and point A is 12 cm.
*July 25, 2011*

**physics**

Consider two current carrying wires shown below. The current in the wire 1 is 4.5 A in the positive x direction. Find the magnitude and direction of the current in wire 2 if the net magnetic field at point A is to be 7.5 μT in the positive z direction (coming out of the ...
*July 25, 2011*

**Physics**

The conducting rod ab shown below makes frictionless contact with metal rails ca and db. The apparatus is in a uniform magnetic field of 0.855 T, perpendicular to the plane of the figure. The length L of the rod is 25 cm. (a) Find the magnitude of the emf induced in the rod ...
*July 24, 2011*

**Physics**

The conducting rod ab shown below makes frictionless contact with metal rails ca and db. The apparatus is in a uniform magnetic field of 0.855 T, perpendicular to the plane of the figure. The length L of the rod is 25 cm. (a) Find the magnitude of the emf induced in the rod ...
*July 24, 2011*

**Physics**

But that only gives me the force. I need the charge to help me find electric field
*July 17, 2011*

**Physics**

A proton is released from rest in a uniform electric field. After the proton has traveled a distance of 10.0 cm, its speed is 1.4 x 106 m/s in the positive x direction. Find the magnitude and direction of the electric field.
*July 17, 2011*

**physics**

Find the magnitude and direction of the net electrostatic force exerted on the point charge q3 in the figure below, where q = +2.5 μC and d = 28 cm. The picture is of a square. q1=+q, q2=-2q, q3=-3q, q4=-4
*July 17, 2011*

**physics**

Find the magnitude and direction of the net electrostatic force exerted on the point charge q3 in the figure below, where q = +2.5 μC and d = 28 cm. The picture is of a square. q1=+q, q2=-2q, q3=-3q, q4=-4
*July 17, 2011*

**Physics**

Ok that makes much more sense. Thank you for your help!
*July 15, 2011*

**Physics**

I dont understand what you're trying to say when you're saying to add. Can you elaborate more?
*July 15, 2011*

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