Sunday

September 25, 2016
Total # Posts: 526

**chem**

How much heat is required to raise the temperature of 200 g CH3OH from 20 to 30 degrees and then vaporize it at 30 degrees. The molar heat capacity of CH3OH is 81.1 J/Mol/K. Okay...the answer is approximately around 254. It was a homework problem. The question is how do you ...

*February 15, 2010*

**Chemistry**

thank you very much. my chemistry is very rusty so i need a refresher.

*February 15, 2010*

**Chemistry**

1.) A vapor volume of 1.17 L forms when a sample of liquid CH3CN absorbs 1.00 KJ of heat at its normal boiling point (81.1 C and 1 atm). What is the heat of vaporization in KJ per moles of CH3CN? 2.) The vapor pressure of water at 25 C is 23.76 torr. If a 1.25 g sample of H20 ...

*February 15, 2010*

**chemistry**

How much heat is required to raise the temperature of 200 g CH3OH from 20 to 30 degrees and then vaporize it at 30 degrees. The molar heat capacity of CH3OH is 81.1 J/Mol/K. Okay...the answer is approximately around 254. It was a homework problem. The question is how do you ...

*February 13, 2010*

**chemistry**

Btw what do I do about the molar heat capacity

*February 13, 2010*

**chemistry**

hm...I dont remember posting this problem but thank you again dr.bob, I can definetly always count on you

*February 13, 2010*

**chemistry**

How much heat is required to raise the temperature of 200 g CH3OH from 20 to 30 degrees and then vaporize it at 30 degrees. The molar heat capacity of CH3OH is 81.1 J/Mol/K. Okay...the answer is approximately around 254. It was a homework problem. The question is how do you ...

*February 13, 2010*

**chem**

The normal melting point of copper is 1357 K and heat of fusion of Cu is 13.05 KJ. How much heat, in kilojoules, is evolved when a 3.70 kg sample of of molten Cu freezes?

*February 11, 2010*

**Chem.**

nevermind i had it right the whole time. thank you

*February 10, 2010*

**Chem.**

Benzene has a heat of vaporization of 30.72 kj/mol and a normal boiling point of 80.1 degrees celcius. At what temperature does Benzene boil when the external pressure is 440 torr? Since...I didn't get the right answer. I'll just show my work and see if anyone can help...

*February 10, 2010*

**Chem.**

nevermind. i got it. thank you dr. bob for showing me how to do it tho

*February 10, 2010*

**Chem.**

I solved it and got 42.94 torr, so by 2 sig figs i rounded it up to 43 torr. What did you get?

*February 10, 2010*

**Chem.**

Ethanol has a heat of vaporization of 38.56 KJ/Mol. And a normal boiling point of 78.4 degrees celcius. WHAT is the vapor pressure of ethanol at 18 degrees celcius?? Okay...I dont really get out to solve for it actually. ln (P2/760 torr)= -38560/8.3145 * (1/291.15 - 1/351.15...

*February 10, 2010*

**Chem. **

Benzene has a heat of vaporization of 30.72 kj/mol and a normal boiling point of 80.1 degrees celcius. At what temperature does Benzene boil when the external pressure is 440 torr?

*February 10, 2010*

**Chem.**

Thanks. But I'm still getting it wrong, cause maybe the sig figs are off by a little. What did you get for this problem?

*February 10, 2010*

**Chem.**

Ethanol has a heat of vaporization of 38.56 KJ/Mol. And a normal boiling point of 78.4 degrees celcius. WHAT is the vapor pressure of ethanol at 18 degrees celcius??

*February 10, 2010*

**Computer Science**

Haha yeah thanks i already figured it out. thank you tho

*February 8, 2010*

**Computer Science**

I tried the / but that didnt worked either =[

*February 8, 2010*

**Computer Science**

This is the problem: The following HTML code fragment contains a reference to an image file called frog.gif and with alternate text set to froggy, but the code as written contains a number of errors. Write the HTML line correctly. <IMG SCR=frog.gif ALT=froggy> (Note: ...

*February 8, 2010*

**Literary Analysis and Composition**

Are you sure this is a solid b+

*January 21, 2010*

**math**

pentagon

*January 20, 2010*

**math**

what do you call a closed figure made up of line segments?

*January 20, 2010*

**childcare**

ANSWER 11-13

*December 16, 2009*

**math**

Sandra has eight coins witch total $0.87. what coins does she have (Hint:make a chart or a list)

*December 3, 2009*

**8th grade**

how do i find antony for words in my weglish class.

*November 2, 2009*

**math**

write each decimal as a percent and as a fraction in the lowest terms

*October 27, 2009*

**History**

Federalist

*October 27, 2009*

**gOVERNMENT**

marbury vs madison mcculloch vs Maryland dred scott decision plessy vs ferguson brown vs board of education roe vs wade bowers vs hardwick mapp vs ohio bakke decisioN What amendments are these linked to and rights related to.

*October 17, 2009*

**Science**

how to find length volume and mass

*October 11, 2009*

**sports puzzle**

I have puzzle to solve on words from the world of sports.Do you know any web or side that can help .

*September 10, 2009*

**algebra**

What is the set of numbers belonging to an absolute number

*August 27, 2009*

**Finance**

Write a 200- to 300-word description of the four time value of money concepts: present value, present value of an annuity, future value, and future value of annuity. Describe the characteristics of each concept and give an example of when each would be used

*August 13, 2009*

**biology**

What is the outer edge of a cheek cell called? please urgent homework due tommorow

*August 8, 2009*

**Literature (short story)**

11. Twain's account of Colonel Rall's speech ("full of gunpowder and glory") is contrasted most vividly to the Marion Ranger's collective remorse over A. the strange affair at "Camp Desolation." B. the shooting of an unarmed rider. C. rebuffing ...

*June 19, 2009*

**math**

1) A gardener wants to plant flowers 10 feet form the base of a flag pole. When he has completed the task, describe in detail what geometric shape the planted flowers will form? 2) Describe the locus of points 5 units from the line whose equation is y=3 on a coordinate graph. ...

*April 23, 2009*

**reading**

milkweed jerry spinelli what dop you think the fox-face furs with beady black eyes symbolize?

*March 26, 2009*

**reding**

milkweed jerry spinelli what do you think the black horse on the merry-go-round might have symbolized?

*March 26, 2009*

**reading**

jerry spinelli milkweed what is the dramatic irony in the scene when misha accompanies janina`s family on their way to the ghetto? what is the effect of this device?

*March 26, 2009*

**chemistry**

CH=78g/mol but the relative atomic mass of C=12 and H=1 therefore the molecular mass would be (12+1)n=78 g/mol 13n = 78 g/mol n=6 the molecular formula is C6H6 .

*March 24, 2009*

**algebra**

Under what situation would one or more solutions of a rational equation be unacceptable? Give an example.

*March 19, 2009*

**grammar**

fourthly,he went fishing with his pal. correct grammer.

*March 15, 2009*

**College Level Probability**

4 and5

*February 23, 2009*

**english 10**

is that he answer

*February 22, 2009*

**english 10**

create five figures of speech by comparing one word in column A with column B A B wind mountain athlete stare forest blast best ernerald paper hum

*February 22, 2009*

**Math**

Joe and Anna collect football cards.The greatest common factor of the numbers of cards in their collections is 15.Altogether Joe and Anna have 75 cards.If Joe has more cards than Anna,how many cards do they each have?

*February 19, 2009*

**3rd grade**

Thanks

*February 19, 2009*

**3rd grade**

identify fraction relationships 5/10 of 20=

*February 19, 2009*

**Math**

identify fraction relationship of 5/10 of 20=

*February 19, 2009*

**Chemistry/Science**

Can you check my answers thanks. Directions: State which statements are true and false. 1. Carbon atoms can bond together in straight chains, branched chains, or rings. Answer: True 2. Isomers are compounds with the same simple formula but different three dimensional ...

*February 3, 2009*

**Poem: A Voice by Pat Mora**

Do you want to poop or fart???

*January 26, 2009*

**American History**

Who was the man who championed the conquered province view of the South in the Reconstruction period abd wanted to give each freedman "40 acres and a mule" to them economic viability?

*December 1, 2008*

**math**

the perimeter of a rectangle is 24 inches. find teh dimensions if the length is 3 inches greater than its width

*November 11, 2008*

**soical studies**

what are pennsylvania 5 natural regions?

*November 8, 2008*

**government**

Why are they majority and minority whips important?

*October 28, 2008*

**Pre Calculus**

how do you find additional points on a line with a slope of 1/2 and a given point of (7,-2)?

*September 7, 2008*

**pre Calculus**

how do you find additional points on a line with a slope of 1/2 and a given point of (7,-2)? im sorry but i still cant get an answer for this question.

*September 7, 2008*

**Pre Calculus**

thanks now i get it

*September 7, 2008*

**Pre Calculus**

please help me with this problem? I don't know how ro do it. please show me step by step. Write the slope intercept form the equations of the lines through the given point parallel to the given line and (B) perpendicular to given line. point slope ((7,-2) m= 1/2

*September 7, 2008*

**Pre Calculus**

i still don't get how to do it

*September 7, 2008*

**Pre Calculus**

please help me with this problem? I have the answer but I need to know how to do it. Write the slope intercept form the equations of the lines through the given point parallel to the given line and (B) perpendicular to given line. point slope ((7,-2) m= 1/2

*September 7, 2008*

**PrecCalculus**

please help me with this problem? I have the answer but I need to know how to do it. Use the point on the line and the slope of the line to find three additional points through which the line passes point slope ((7,-2) m= 1/2

*September 7, 2008*

**precalc: elimating the parameter**

THANK YOU. i just really needed that bit of a start; now i can finish the rest. thanks again!

*July 9, 2008*

**precalc: elimating the parameter**

hi, i'm having trouble understanding the concept of eliminating the parameter to obtain an equation in x and y alone. can anyone please solve this problem and explain it? thank you so much. x = 3T-4 y= = 1-2T (0<t<3) those signs are actually less than or equal to.

*July 9, 2008*

**chemistry**

For the reactions that occurred spontaneously in the individual tables, balance these reactions assuming they are in an acidic solution. Reaction 1: Cu I^- Ag Br^- Reaction 2: Zn Pb Cu Ag Reaction 3: Cl2 Br2 I2 Reaction 1 I 2(aq) Cu2 + (aq) Ag + (aq) Br2 (aq) Reaction 2 Ag + (...

*April 15, 2008*

**chemistry**

"However, the Ag^+ + I^- reacted to give AgI (but that is not a redox reaction) and if they reacted why didn't Br^- and Ag^+?" Hi Dr.Bob, I am also given additional information for reaction #1 Cu(s) I-(aq) Ag(s) Br- (aq)

*April 15, 2008*

**chemistry**

Reaction 1 I 2(aq) Cu2 + (aq) Ag + (aq) Br2 (aq) Reaction 2 Ag + (aq) Pb2 + (aq) Cu2 + (aq) Zn2 +(aq) Reaction 3 Br - (aq) Cl - (aq) I - (aq)

*April 14, 2008*

**chemistry**

ONe more question DrBob :) For the reactions that occurred spontaneously in the individual tables, balance these reactions assuming they are in an acidic solution. Thanks for any further assistance we appreciate it

*April 14, 2008*

**chemistry**

Of the reactions that occurred spontaneously in the individual tables, what types of qualitative changes would you observe that would indicate the reaction is proceeding?

*April 14, 2008*

**chemistry**

Reaction 1: I2(aq)Cu^+2(aq) Ag^+(aq)Br2(aq) Column 1---Column 2---Column 3---Column 4---Column 5 I-(aq)---X---X---T---T Cu(s)---T---X---T---T Ag(s)---X---X---X---T Br-(aq)---X---X---X---X Reaction of metals and solution of ions Reaction 2: Ag+(aq)Pb2+(aq)Cu2+(aq)Zn2+(aq) ...

*April 14, 2008*

**chemistry**

I found a pattern and I was wondering if it applies to all reactions. The more times there is evidence of a redox reaction occuring for an element, the higher this element will be on the list?

*April 14, 2008*

**chemistry**

I found a pattern and I was wondering if it applies to all reactions. The more times there is evidence of a redox reaction occuring for an element, the higher this element will be on the list?

*April 14, 2008*

**chemistry**

"Ag(s) reacts with none of the 4 (solutions of Ag^+2, Pb^+2, Cu^+2, Zn^+2}. So Ag(s) goes at the bottom of the table for now although there may be some metals below silver when you finish with the entire table. Cu(s) reacts with (Ag^+ solution) so Cu goes above Ag ion. It...

*April 14, 2008*

**chemistry**

When I finish with the other two reactions, would you mind reviewing my work?

*April 13, 2008*

**chemistry**

*Forgot to add, reaciton 3 is Br-(aq) Cl-(aq) I-(aq)

*April 13, 2008*

**chemistry**

Purpose: The purpose of this lab excersise is to construct a table of relative strengths of oxidizing and reducing agents. By completing this excersise, you will see how extensive tables of relative strengths of oxidizing and reducing agents have been developed. Procedure: ...

*April 13, 2008*

**chemistry**

No problem, I will write it as you say:)

*April 13, 2008*

**chemistry**

Hi I sent this question a few days ago but did not get it answered I think it may have been mixed up in the jumble. Purpose: The purpose of this lab exercise is to construct a table of relative strengths of oxidizing and reducing agents. By completing this exercise, you will ...

*April 13, 2008*

**chemistry**

Hi I sent this question a few days ago but did not get it answered I think it may have been mixed up in the jumble. Purpose: The purpose of this lab exercise is to construct a table of relative strengths of oxidizing and reducing agents. By completing this exercise, you will ...

*April 13, 2008*

**chemistry**

Purpose: The purpose of this lab exercise is to construct a table of relative strengths of oxidizing and reducing agents. By completing this exercise, you will see how more extensive tables of relative strengths of oxidizing and reducing agents have been developed. Procedure: ...

*April 12, 2008*

**chemistry**

*Please note For table 1 I2(aq), Cu2+(aq), Ag+(aq) and Br2(aq) are supposed to be shifted to the right since they are horizontal. I-(aq), Cu(s), Ag(s) and Br-(aq) are vertical. For table 2 Ag+(aq), Pb2+(aq), Cu2+(aq) and Zn2+(aq) are supposed to be shifted to the right since ...

*April 11, 2008*

**chemistry**

Purpose: The purpose of this lab exercise is to construct a table of relative strengths of oxidizing and reducing agents. By completing this exercise, you will see how more extensive tables of relative strengths of oxidizing and reducing agents have been developed. Procedure: ...

*April 11, 2008*

**chemistry**

Sorry.... the tables not supposed to turn out liek that. Can anyone show me how the table can be improved? Table 1: 4 vertical columns, 4 horizontal columns (on top) Table 2: 4 vertical columns, 4 horizontal columns (on top) Table 3: 3 vertical columns, 3 horizontal columns (...

*April 11, 2008*

**chemistry**

Lab: Creating a Redox Table Purpose: The purpose of this lab exercise is to construct a table of relative strengths of oxidizing and reducing agents. By completing this exercise, you will see how more extensive tables of relative strengths of oxidizing and reducing agents have...

*April 11, 2008*

**chemistry**

19 mL of 0.50 mool/L NaOH which is standardized becomes titrated alongside 24 mL of 0.44 mol/L acetic acid. Determine the pH of the solution Please judge my work: Becasue NaOH and acetic acid react in a 1:1 ratio, initital moles of acetic acid =0.0019 L x 0.44M = 0.000836 mols...

*April 9, 2008*

**chemistry**

An AgNO3 solution (44 mL/0.44 M) has been mixed with an NaCl solution (83 mL/1.35x 10^-2 M) a)Determine the ion product of the precipitate(potential precipitate) b) Would a precipitate be created? The Ksp of AgCl(s) proves to be 1.8 x 10^-10

*April 9, 2008*

**chemistry**

22 mL of 0.37 mol per litre acetic acid is titrated by way of a standardized 0.29 mol/L KOH solution. Calculate the pH of the solution after roughly 18 mL of the solution of KOH is added. The Ka of acetic acid proves to be 1.8 x 10^-5

*April 9, 2008*

**chemistry**

Calculate the pH of a 1.33 mol/L solution of HCN is the Ka value of HCN is 6.2x10^-12

*April 9, 2008*

**geometry**

The simplests example of a magic square is a 3 by 3 grid. The tasks is to place the numbers 1-9 in the grid, on number per box using each number exacely once so that the sum of three in a row in and direction is the same. can you help?

*April 8, 2008*

**math riddle ALGEBRA WITH PIZZAZZ**

thank you rosa

*April 6, 2008*

**cook**

what kitchen utensil or equipment starts with the letter "A"

*March 24, 2008*

**Calculus**

I'm having trouble with this one. Problem: Find the equations for the planes parallel to x+2y-2z=1 and two units away from it.

*February 2, 2008*

**math**

this is due tomorrow

*January 15, 2008*

**math**

i have the same problem and im stuck too

*January 15, 2008*

**math**

IDK... my BFF Jill?

*January 15, 2008*

**Math**

Construct a Truth Table for the given statement: 1. p implies ~(pVq) 2. ~(p AND q)Vp

*December 16, 2007*

**Math**

Construct a Truth Table for the given statement: 1. p implies ~(pVq) 2. ~(p AND q)Vp

*December 15, 2007*

**Math**

Construct a Truth Table for the given statement: 1. p implies ~(pVq) 2. ~(p AND q)Vp I thought this is how to do it, but my teacher marked it incorrect: 1. p q ~(pVq) p implies ~(pVq) T T F T implies T= T T F F T implies F= F F T F F implies F= T F F T F implies T= T 2. p q ~(...

*December 15, 2007*

**Math- Truth Tables**

Construct a Truth Table for the given statement: 1. p implies ~(pVq) 2. ~(p AND q)Vp I thought this is how to do it, but my teacher marked it incorrect: 1. p q ~(pVq) p implies ~(pVq) T T F T implies T= T T F F T implies F= F F T F F implies F= T F F T F implies T= T 2. p q ~(...

*December 15, 2007*

**Math- Truth Tables**

This was my guess for #2: p q ~(p AND q) ~(p AND q)Vp T T F FVT= T T F T TVT= T F T T TVF= T F F T TVF= T

*December 15, 2007*

**Math- Truth Tables**

ok

*December 15, 2007*