Sar

Most popular questions and responses by Sar
1. Mole fraction of a vapor pressure?

If 0.380 mol of a nonvolatile nonelectrolyte are dissolved in 3.00 mol of water, what is the vapor pressure P(H2O) of the resulting solution? The vapor pressure of pure water is 23.8 torr at 25 C. I got this answer correct: 21.1 torr A solution is composed

2. torque

A meterstick is found to balance at the 49.7 cm mark when placed on a fulcrum. When a 50.0g mass is attached at the 10.0cm mark, the fulcrum must be moved to the 39.2 cm mark for balance. What is the mass of the meterstick? All of the problems ive been

3. Mole fractions in a liquid mixture:

Acetone, C3H6O, and ethyl acetate, C4H8O2, are organic liquids often used as solvents. At 30 degrees C, the vapor pressure of acetone is 285 mm Hg and the vapor pressure of ethyl acetate is 118mm Hg. the solution is prepared at 30 degrees C by dissolving

4. Chemistry

How can i rearrange this Clausius-Clapeyron equation so that 1/T2 is on one side? In P2/P1=delta H vaporization/R (1/T2- 1/T1) I am trying to find at At what temperature does acetone have Pvap= 111 mm Hg. Acetone, a common laboratory solvent, has Delta H

5. Chemistry: Raoult's Law

If 0.380 mol of a nonvolatile nonelectrolyte are dissolved in 3.00 mol of water, what is the vapor pressure P(H2O) of the resulting solution? The vapor pressure of pure water is 23.8 torr at 25 C. I got this answer correct: 21.1 torr A solution is composed

6. physics

two masses are in the ratio 1:2 are thrown vertically up with the same speed . what is the effect on time by the mass?

7. Physics 1111: Orbitals and Distance

A planet has two satellite moons. Moon X has an orbital period of 2.27 days. Moon Y has an orbital period of about 3.40 days. Both moons have nearly circular orbits. Use Kepler's third law to find the distance of each satellite from the planet's center.

8. Physics 1112 Electric charge

As shown in the figure, a square has sides of 8.0 cm with a charge of +6.0 µC at one corner (a) and with charges of -2.0 µC at the remaining three corners (b, c, and d). The figure is just a square with no measurements. Corner a being the top left

9. Physics

A uniform magnetic field points north; its magnitude is 3.5 T. A proton with kinetic energy 6.0 × 10-13 J is moving vertically downward in this field. What is the magnetic force acting on it? This is what I've done. The answer is incorrect. Please help me

10. Magnetic Field Forces: Physics

A uniform magnetic field points north; its magnitude is 3.5 T. A proton with kinetic energy 6.0 × 10-13 J is moving vertically downward in this field. What is the magnetic force acting on it? This is what I've done. The answer is incorrect. Please help me

11. Physics: Angular Width. Why is my answer wrong?

A beam of yellow laser light (590 nm) passes through a circular aperture of diameter 5.0 mm. What is the angular width of the central diffraction maximum formed on a screen? I can't seem to get this answer right. I don't think I am finding the first part

12. Physics: Diameter of a nichrome wire

If 49 m of nichrome wire is to have a resistance of 13.0 ohms at 20°C, what diameter wire should be used? I've done this: (108e-8)(49)/10.0 ohms = 5.29e-6m^2 Then 5.29e-6m^2/pi then r = sqrt(1.68e-6m^2) and got .00129 = 1.29e-3 1.29mm r=2(1.29mm) = 2.58mm

13. finding boiling points of solutions

What is the boiling point (in degrees Celsius ) of each of the solutions below? For water, Kb = 0.51 (Degrees C * kg)/mol The vapor pressure of water at 45.0C is 71.93 mm Hg. 1. A solution of 15.0g of urea, CH4N2O, in 164 g of water at 45.0 degrees C. For

14. Physics: Angular Width. Why is my answer wrong?

A beam of yellow laser light (590 nm) passes through a circular aperture of diameter 5.0 mm. What is the angular width of the central diffraction maximum formed on a screen? I can't seem to get this answer right. I don't think I am finding the first part

15. Physics: Focal length why is my answer wrong?

An old refracting telescope in a museum is 44.0 cm long and the caption states that the telescope magnifies images by a factor of 29.0. Assuming these numbers are for viewing an object an infinite distance away with minimum eyestrain, what is the focal

16. Second order half life

At 100 degrees C , a certain substance undergoes second-order decomposition with a half-life of 26 minutes. If the initial concentration of the substance is 3.9×10−2M , what is the value of the rate constant at 100degrees C? So I put in (1560seconds)

17. chem

which of these substances dissolve in water? and are they elements or compounds? copper nitrate sodium hydroxide copper hydroxide copper oxide hydrochloric acid aluminum copper chloride hydrochloric acid

18. geometrey

a chord of 42 cm with the distance of 5 cm from center of the circle find the raduis of the circle?/.

19. math:solving for an exponent.

I can't get the right answer, where am I going wrong? 7.0x10^9= (6.7x10^9)(2.72^r*3) 1.04 = 2.72^r*3 When I solve for this, I get ln (1.40) = 0.03922 then 0.03922 / 3 = 0.0130 So my r equals 0.0130 BUT the teacher says the answer is 0.05 = r *3 0.02 = r

20. geometrey

whats a circle?

1. Algebra II

h=1+13t-5t²

posted on August 23, 2015
2. math:solving for an exponent.

Bob, thank you. I thought I was going insane there for a minute. I guess the professor made a mistake. We are all human (but it drives me crazy when I'm trying to study haha)

posted on October 4, 2011
3. math:solving for an exponent.

No. The math he did was handwritten. I guess he must have made a mistake because this is driving me nuts. Everything listed in my post is CORRECTLY copied from the piece of paper I got it on.

posted on October 4, 2011
4. Physics: Angular Width. Why is my answer wrong?

Well, that was a step my teacher did so I just followed it. However, .00082 degrees is not the correct answer either (or the variant of 8.2e-4). So I am just totally lost on this one. :/

posted on November 12, 2010
5. history

The causes of Sand Creek massacre were rooted in the decades-long conflict for control of the Great Plains of eastern Colorado. The Fort Laramie Treaty of 1851 guaranteed ownership of the area north of the Arkansas River to the Nebraska border to the

posted on November 12, 2010
6. Physics: Angular Width. Why is my answer wrong?

I have also tried using the positive of the angular width. But that is wrong, too. I used the same equation as i did above but with the 1.22

posted on November 9, 2010
7. Physics: Angular Width. Why is my answer wrong?

I just tried the problem with 1.22 and i got -1.21 as my final angular width. However, this is also incorrect. any ideas where I am going wrong?

posted on November 9, 2010
8. Physics: Focal length why is my answer wrong?

posted on October 28, 2010
9. Second order half life

You are most correct, I did not. Thank you so much.

posted on September 21, 2010
10. Physics: Diameter of a nichrome wire

2.27mm is the new answer I got, which is correct. Thanks for pointing that out, Bob. I was going insane trying to figure this out.

posted on September 9, 2010
11. Physics: Diameter of a nichrome wire

Ooo. Gosh, I must have just been looking at the wrong number or something. I feel silly now.

posted on September 9, 2010
12. Mole fractions in a liquid mixture:

When I did that I got this: 2.6 for acetone mole fraction 1.4 for ethyl acetate mole fraction 119 acetate vapor 30 ethyl acetate vapor None of those answers were correct. :[

posted on September 2, 2010
13. Mole fraction of a vapor pressure?

I see where i went wrong. I was trying to take the mole fraction (.405) and divide it into the 176. Thank you.

posted on September 2, 2010
14. Chemistry: Raoult's Law

i got the mole fraction of cyclohexane in the solution but that isn't what it wants and I don't know exactly what the question is asking for. Can someone please explain to me how to do this problem?

posted on September 2, 2010
15. Chemistry

Thank you very much!

posted on August 23, 2010
16. Physics 1112 Electric charge

Still couldn't get the correct answer :[

posted on August 23, 2010