Thursday

July 31, 2014

July 31, 2014

Total # Posts: 48

**Chemistry**

Where would I add that in to my calculation? Like would it look like this: -Lattice energy of MX2=-891-(141+88.5+605+1392-678)

**Chemistry**

Consider an ionic compound, MX2, composed of generic metal M and generic halogen X. The enthalphy of formation of MX2= -891. The enthalphy of sublimation of M= 141. The first and second ionization energies of M are 605 and 1392. The electron affinity of X= -339. The bond energ...

**Chemistry**

But what is the wavelenght? Do I use 5.40 nm?

**Chemistry**

I am having difficulty determining what would be the wavelength that I use to determine the velocity using de Broglie's equation.

**Chemistry**

To resolve an object in an electron microscope, the wavelength of the electrons must be close to the diameter of the object. What kinetic energy must the electrons have in order to resolve a protein molecule that is 5.40 nm in diameter? Take the mass of an electron to be 9.11&...

**Chemistry**

Basically what I have found is: 1) excited Lu 2) He 3) excited Ca 4) V 5) Mo

**Chemistry**

I have counted the electrons for all of the five electron configurations. I have determined that as you mentioned [Xe]6s2 4f1 is the excited state of Lu. I also managed to find that the configuration 1s2 2s2 2p6 3s2 3p6 3d2 is the excited configuration of Ca. But I am told tha...

**Chemistry**

Which of the following electron configurations of neutral atoms represent excited states? ( ) [Xe]6s24f1 ( ) 2s2 ( ) 1s22s22p63s23p63d2 ( ) [Ar]4s23d3 ( ) [Kr]5s14d5

**Chemistry**

Thanks.

**Chemistry**

For each electron in a ground-state Be atom, select the set of quantum numbers that represents it. Check all that apply. ( ) n=2, l=0, ml=0, ms=+1/2 ( ) n=1, l=0, ml=0, ms=+1/2 ( ) n=2, l=1, ml=0, ms=-1/2 ( ) n=2, l=1, ml=1, ms=+1/2 ( ) n=2, l=0, ml=0, ms=-1 ( ) n=2, l=0, ml=0...

**Chemisty**

I keep getting the answer to the volume of the atmosphere wrong. Are my calculations correct? Or what is my problem? I calculate that the total volume of Earth + thickness of atmosphere is: (4/3)*pi*(6450000 m)^3 = 1.124*10^21 I then calculate that the volume of the Earth is: ...

**Chemisty**

It is not one question. It is a series of questions. First calculate the total volume of the atmosphere. Second calculate the total number of gas molecules in the atmosphere. Third calculate the number of gas molecules in Caesar's last breat. Fourth calculate what fraction...

**Chemisty**

Enrico Fermi was a famous physicist who liked to pose what are now known as Fermi problems in which several assumptions are made in order to make a seemingly impossible estimate. One example of a Fermi problem is "Caesar's last breath" which estimates that you, r...

**Chemistry**

I calculated the molar mass to be approximately 29 g/mol. Although I am not entirely sure whether that is the correct answer or not.

**Chemistry**

Dry air (0% humidity) is approximately 78% N2, 21% O2, and 1% Ar by moles. Calculate the molar mass and density of dry air at 0 °C and 1.0 atm. Assume ideal behavior and use two significant figures in your answers.

**Chemistry**

A 7.30-L container holds a mixture of two gases at 45 °C. The partial pressures of gas A and gas B, respectively, are 0.342 atm and 0.527 atm. If 0.250 mol a third gas is added with no change in volume or temperature, what will the total pressure become?

**Chemistry**

Thanks. :)

**Chemistry**

The organic compound di-n-butyl phthalate, C16H22O4(l), is sometimes used as a low-density (1.046 g·mL–1) manometer fluid. Compute the pressure (in torr) of a gas that supports a 555-mm column of di-n-butyl phthalate. The density of mercury is 13.53 g·mL...

**Chemistry**

Makes sense now. Thank you.

**Chemistry**

So would it look like this: 2.40*752=P2*931 for gas 1 4.80*179=P2*931 for gas 2 Then add the two P2's that I get. Right?

**Chemistry**

I am having trouble trying to figure out what formula I can use to determine the partial pressure of each. Is it Boyle's Law?

**Chemistry**

Container A holds 752 mL of ideal gas at 2.40 atm. Container B holds 179 mL of ideal gas at 4.80 atm. If the gases are allowed to mix together, what is the resulting pressure? Note: Find the partial pressure of each gas in the total volume using a formula that relates volume a...

**physics college**

A military gun is mounted on a railroad car (m = 1400 kg) as shown in the figure below There is no frictional force on the car, the track is horizontal, and the car is initially at rest. The gun then fires a shell of mass 31 kg with a velocity of 285 m/s at an angle of 35°...

**Chemistry**

Liquid sodium is being considered as an engine coolant. How many grams of liquid sodium (minimum) are needed to absorb 3.60 MJ of energy (in the form of heat) if the temperature of the sodium is not to increased by more than 10.0 °C? Use CP = 30.8 J/(K·mol) for Na(l...

**physics**

What is the speed of a satellite in a geosynchronous orbit about Earth?

**physics**

An airplane flies from Boston to San Francisco (a distance of 5000 km) in the morning, then immediately returns to Boston. The speed of the plane relative to the air is 240 m/s. The wind is blowing at 41 m/s from west to east, so it is "in the face" of the plane on t...

**physics**

In recent years, a number of nearby stars have been found to possess planets. Suppose, the orbital radius of such a planet is found to be 3.0 1011 m, with a period of 980 days. Find the mass of the star.

**physics**

The region of the solar system between Mars and Jupiter contains many asteroids that orbit the Sun. Consider an asteroid in a circular orbit of radius 5.7 1011 m. Find the period of the orbit.

**physics**

Suppose that the swimmer in the figure below has a swimming speed relative to the water of 0.44 m/s, while the speed of the current is 2.0 m/s. If it takes the swimmer 180 s to cross the river, how wide is the river?

**physics**

You are an astronaut (m = 90 kg) and travel to a planet that is the same mass and size as Earth, but it has a rotational period of only 15 h. What is your apparent weight at the equator of this planet?

**physics**

Consider the swimmer in the figure below. Suppose that his swimming speed relative to the water is 5.7 m/s, current = 2.2 m/s, and that the river is 10 m wide. How long will it take for him to cross the river?

**physics**

When a spacecraft travels from Earth to the Moon, the gravitational force from Earth initially opposes this journey. Eventually, the spacecraft reaches a point where the Moon's gravitational attraction overcomes the Earth's gravity. How far from Earth must the spacecra...

**physics**

A roller coaster track is designed so that the car travels upside down on a certain portion of the track as shown in the figure below. What is the minimum speed the roller coaster can have without falling from the track? Assume the track has a radius of curvature of 20 m.

**physics**

A stone of mass 0.33 kg is tied to a string of length 0.65 m and is swung in a horizontal circle with speed v. The string has a breaking-point force of 45 N. What is the largest value v can have without the string breaking?

**Physics**

A compact disc spins at 2.7 revolutions per second. An ant is walking on the CD and finds that it just begins to slide off the CD when it reaches a point 2.8 cm from the CD's center.

**Physics**

Consider again the problem of a car traveling along a banked turn. Sometimes roads have a "reversed" banking angle. That is, the road is tilted "away" from the center of curvature of the road. If the coefficient of static friction between the tires and the ...

**social studies**

i connot understand social studies

**Psychology**

Jennifer is a 29-year-old administrative assistant married to Antonio, an Italian engineer, whom Jennifer met four years earlier while on a business trip for her marketing company. The couple now lives in Nebraska, where Antonio works for the county's transportation depart...

**Psychology**

Ok thanks, i was in betwwen congnitive and humanistic.

**Psychology**

Psychodynamic Therapies Humanistic-Existential Therapy Behavior Therapy Cognitive Therapies Group, Couples, and Family Therapy

**Psychology**

Jennifer is a 29-year-old administrative assistant married to Antonio, an Italian engineer, whom Jennifer met four years earlier while on a business trip for her marketing company. The couple now lives in Nebraska, where Antonio works for the county's transportation depart...

**math**

Well you see that answer does not match with one of the multiple choice rather it's and we know that it's not D so I'm assuming it's A then. A) 204 : 13 B) 191 : 13 C) 13 : 204 D) 13 : 191

**math**

D) 13 : 191

**Math 117**

I have gotten the answer already I have worked out the problem and I came up with 3.60 I mult. across. then added the answers all together..

**Math 117**

Can some one please help me with this one...

**Math 117**

The random variable x is the number of houses sold by a realtor in a single month at the Sendsom's Real Estate office. Its probability distribution is as follows. Find the expected number of houses sold in a month. Houses Sold (x) Probability P(x) 0 0.24 1 0.01 2 0.12 3 0....

**Math 156**

Can some one give me some hints please..

**Math 156**

bobpursley on the first one it's a mult. choice which I have A) $0.00 B) -$1.00 C) -$0.85 D) -$0.83 where did you get $17 though? I don't understand this one.

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