Tuesday

February 21, 2017
Total # Posts: 554

**chemistry**

A small “coffee cup” calorimeter contains 110. g of H2O at 22.0°C. A 100. g sample of lead is heated to 90.0°C and then placed in the water. The contents of the calorimeter come to a temperature of 23.9°C What is the specific heat of lead?

*August 3, 2010*

**Chemistry**

A gaseous mixture of O2, H2, and N2 has a total pressure of 1.50 atm and contains 8.20 g of each gas. Find the partial pressure of each gas in the mixture They don't give you Volume and Temperature. Please explain it to me, thank you!

*August 2, 2010*

**chemistry**

Sterling silver, an alloy of silver and copper, contains 7.5 percent copper by mass and has a density of 10.3 g/cm3. How many copper atoms are in a sterling silver sphere whose radius is 2.0 in?

*August 2, 2010*

**chemistry**

Calculate the molarity of the solution produced by mixing (a) 50.0 ml of 0.200 M NaCl and 100.0 ml of 0.100 M NaCl;

*July 27, 2010*

**Chemistry**

how many hours are in a day? 12! So... just take the 6 as the numerator and the 12 as the denominator (6/12) and if you simplify so it will be (1/2) and if you turn that into s percentage it will be %50. THE ANSWER IS AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAaa

*July 19, 2010*

**Math**

cool

*May 10, 2010*

**math**

what is 15% of 35?

*April 28, 2010*

**english**

write a pargraph of about 50 words on the topic job seeking is a task that needs courage as well as patience

*April 22, 2010*

**chemistry**

find the mass of solute needed. 3.0 liters of 2.0 M NaOH. or 500ml of 1.5 M NaCl?

*April 20, 2010*

**Grade 12 English - College Assignment**

job seeking and courage

*April 8, 2010*

**12th grade**

cos x sin x

*March 31, 2010*

**stats**

A statistics practitioner formulated the following hypothesis: H0 : ì = 200 against H1 : ì < 200 and learned that x = 190 n = 9 and ó = 50. The p– value of the test is (1) 0.6 (2) 0.2743 (3) 0.7743 (4) −0.2743 (5) Cannot be found with ...

*March 31, 2010*

**stats**

A bakery stated that the average number of breads sold daily is 3000. An employee thinks that the actual value might differ from this and wants to test this statement. The correct hypotheses are: (I think it is 1) (1) H0 : ¦Ì = 3000 H1 : ¦Ì not= ...

*March 31, 2010*

**stats**

A statistics practitioner wishes to test the following hypothesis: H0 : ì = 600 against H1 : ì < 600 A sample of 50 observations yielded the statistics: mean x = 585 and standard deviation sx = 45. The test statistic of a test to determine whether there is ...

*March 31, 2010*

**3rd grade**

ciopanam

*March 23, 2010*

**calculus**

D) would actually be approximately 9.23 seconds. 1362/16=85.125

*March 21, 2010*

**Math209**

Selling shirts. If a vendor charges p dollars each forrugby shirts, then he expects to sell 2000 - 100p shirts ata tournament. a) Find a polynomial R(p) that represents the total revenuewhen the shirts are p dollars each. b) Find R(5), R(10), and R(20). c) Use a bar graph to ...

*March 13, 2010*

**maths**

The plane is flying at an altitude of 8 miles and is 175 miles from the runway, as measured from the ground. What angle will the plane's path make with the runway? Round your answer to the nearest hundredth.

*March 12, 2010*

**Physics**

Hi, I have the following question: 1. The index of refraction for a prism is given by the equation: n = 1.58 − (6.41 x 10^4)λ where λ is the wavelength in meters. Light is incident at 28°. Find the exit angle ß for light of a) 800 nm b) 633 nm c) 540 ...

*March 7, 2010*

**accounting**

What is the Journal Entry for: Sold goods to Smithsons for $700 that costs $300. Terms of n/30 were offered. As a courtesy to Smithsons, $125 of frieght was added to the invoice for which cash was paid directly to the UPS by Opals, INC? Need This answer ASAP!

*February 27, 2010*

**Physics**

The typical resistance of the tungsten filament of a 60 watt incandescent light bulb when it is turned off is 24 ohms and its resistance when operating from a 120 volt power source is 240 ohms. Generally, an incandescent light bulb filament is most likely to “burn out&#...

*February 23, 2010*

**Math 116 algebra**

plug in the x values in the equation to find the y values.

*February 23, 2010*

**Physics**

No, this is all of the information that is provided.

*February 23, 2010*

**Physics**

The nominal resistance R of the resistor used in this experiment was printed on the resistor by the manufacturer. According to the manufacturer, the actual resistance of the resistor should not differ from its nominal value by more than 1%. Does your most accurate measured ...

*February 23, 2010*

**Physics**

This is the question that was provided, no more information.

*February 23, 2010*

**math**

use a calculator!

*February 23, 2010*

**chem**

Benzaldehyde, C6H5CHO}, has a normal boiling point of 179.0 C and a critical point at 422 C and 45.9 atm. Using a phase diagram, estimate its vapor pressure at 125 Degrees (I'm putting this back up again. Since I still didn't understand it but the answer to it was 171 ...

*February 15, 2010*

**chem**

Heat of vap. is 38.9 KJ/mol

*February 15, 2010*

**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 don't 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 don't really get out to solve for it actually. ln (P2/760 torr)= -38560/8.3145 * (1/291.15 - 1/351...

*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 didn't 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 grammar.

*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 the dimensions if the length is 3 inches greater than its width

*November 11, 2008*

**social 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*