# Posts by S

Total # Posts: 506

Physical Chemistry
15.The Rydberg constant for the Be3+ ion is 109731 cm–1. Calculate the ionization energy of a ground-state Be3+ ion. 22.How many electrons can occupy the following subshells: (a) 2s, (b) 4d, (c) 6f, (d) 6g, (e) 6h?

Math
on a map 1/2 inch represents 50 miles. How long would a line need to be to represent 750 miles. so I thought I should divide 750 by 50 than multiply 15 { the answer I got } by 1/2 but I have a feeling its wrong

English Writing
Thank you so much

English Writing
I'm not a native speaker. Can you please teach me? Is this sounds weird? I was worrying to stay in English class. However, she made me feel comfortable and fun to stay her class through every class.

MATH
During halftime of a football?game, a sling shot launches? T-shirts at the crowd. A? T-shirt is launched from a height of 33 feet with an initial upward velocity of 64 feet per second. The? T-shirt is caught 48 feet above the field. How long will it take the? T-shirt to reach ...

Nait
pythagorean theorem!! x^2 (leg 1) + y^2 (leg 2) = z^2 (hypotenuse = the ladder) x^2 = (12)^2 - (8)^2 x^2 = 80 x = sq root (80) ~ 8.944

Math
If u scored 85,89,89,91 on a test but u need an average mean of 90 what will u have to score on ur last test to get 90?

Physics
A horizontal forces of magnitude 500N pulls two blocks of masses m1=10 kg and m2=20 kg which are connected by the light inextensible string and lying on the horizontal frictionless surface. Find the tension in the strings and acceleration of each mass when forces is applied on...

US HISTORY
Who attacked first on the Battle of Little Bighorn??? The natives or the army?

Geology
ss

Culture
As an ABC (Australian Born Chinese), Who is an avid watcher of korean entertainment ( dramas, variety, movies etc), listener of k-pop, watch anime from japan, listen to j-pop, watch chinese tv shows and movies. Having studied German , French . It perplexes me that to this day...

stats
working on the same two questions tonight!

Math
A room is 8 meter long and 6 meter wide.if floor is paved of square tiles then what should be the maximum size of the tile?sole it

Algebra
Hugh earns \$33.33. I am assuming 'they' refers to Leslie and JOhn together.... Set it up like this: 3+H=J 2H-2=L J+L=100 Substitute the first two equations into the third one, and solve for H, and you got it!

Physics
So average acceleration is just the 'slope' of the velocity vs time graph.. The equation would be (Vf - V0)/t = average acceleration... (12.2-3.7)/7.99 = 1.06 m/s^2 because the units are (m/s)/s

AP physics
Since there is air resistance that affects the experimental value for g, it is hard to find that out. If there is an inclined plane that has very little friction, then all that is needed is the angle of the plane with respect to the ground, and the value would be accurate..

Social Studies
The only ones that make any sense are A and C, but I believe the answer is A..

math
A sum of money Lent at simple interest amount to

Calc
find the equation of the line that is tangent to the curve 𝙛(𝑥)= 5 +3x² -x⁵ at the point (1,7)

Chemistry
Static charge can interfere with the production of plastic products by attracting dust and dirt. to reduce it, manufacturers expose the area to polonium-210, which has a half-life of 138 days. How much of a 25.0-g sample will remain after one year (365 days)? N = N0(1/2)t/T...

chemistry
Write the oxidation and reduction half-reactions for a silver-chromium voltaic cell. Identify the anode, cathode, and the direction of electron flow. Ag+ + e-  Ag Cr  Cr2+ + 2e- or Cr  Cr3+ + 3e- ????? Which is the correct equation for the chromium side...

Physics
tf

Spanish
nu

Stat
I typed the question correctly maybe my homework has a typo...

Stat
Mean of 10 observations is 100. One of the observations is dropped from the data. The mean of the remaining observations is 9. What is the value of the dropped observation?

chemistry
the solubility of CaF in water is 7*10^-2 gm/l. find its solubility in 0.5m CaCl2 soln

Pre calc
Give an example of an exponential function that has a range (3,infinity)

Physics
a box of mass 7 kg is pulled up a frictionless 30 degree incline by a force of 381 N which acts parallel to the incline surface. the box has an initial speed of 5m/s and is pulled 9m. what is the speed of the box at the end of the 9m.

Physics
a mass, m = 2.1 kg, is ejected horizontally from a compressed coil with a force constant, k = 5.2 N/m and compression, x = 25 cm, onto a rough ramp that is 1.5 cm long with one end raised to a height, h= 120 cm. the speed at the bottom of the rough ramp is v=+3.037 m/s. the ...

Physics
998114 N

Physics
old faithful geyser in yellowstone park shoots water hourly to a height of 44.8m. with what velocity does the water move when it is at 24.4m above the ground (on its way up)?

Physics
so is it 196 or 191J?

Physics
a block of mass 2kg moves on a frictionless inline (none of the forces on the block are shown). its initial velocity is v initial=3m/s, and it slides a vertical distance h=10m up the slope and its final velocity is v final=2m/s. find the external work done on the block.

Physics
so 14m/s?

Physics
a skier, mass 61 kg is at the top of a hill and starts down with an initial speed of 5m/s. he does no work on the way down, assume that the hill surface is frictionless. find his speed at the bottom of the hill which is 10m below the top.

Physics
determine the point of zero gravitation force, as measured from the centre of earth (mass 5.97 x 10^24 kg) to the sun ( mass 1.99 x 10^30 kg) if the earth-sun distance is 150 x 10^6 km.

Physics
a 1.2 kg magnet is capable of holding up a 0.5 kg mass. the magnet is placed on a vertical refrigerator door and given an initial push so that it slides up the door with an initial velocity of 0.11 m/s. if the coefficient of kinetic friction between the magnet and the door is ...

Physics
a 35 kg child slides down a 26 degree incline. the coefficient of kinetic friction is 0.33. what is her speed after sliding for 2.5 seconds starting from rest?

Physics
help pls

Physics
answers can be: 27.4, 13.2, 14.2, 11.42, 0.5 (all are N)

Physics
A 2kg mass, m1 and a 10 kg mass, m2 are in contact on a horizontal frictionless surface. a constant horizontal force 13.7 N in the positive X direction is applied to m1 and a constant horizontal force 10.7 N in the negative X direction is applied to m2. the masses stay in ...

Physics
a 61.6 kg person on a diet stand on a bathroom scale in an elevator. to their great pleasure the scale reads 46.8 kg. what is the acceleration of the elevator? (up is positive)

Physics
A 2 635-kg sailboat experiences an eastward force of 2 710 N by the ocean tide and a wind force against its sails with magnitude of 5 748 N directed toward the northwest (45° N of W). What is the direction of the resultant acceleration?

Physics
a stone is thrown at an angle of 30 degrees above the horizontal from the top edge of a cliff with an initial speed of 12m/s. a stop watch measures the stone's trajectory time from top of cliff to bottom to be 8s. how far out from the cliff's edge does the stone travel...

Physics
an airplane has a velocity of 499 km/h relative to the moving air. at the same time, a wind blows northward with a speed of 87 km/h relative to the earth. the airplane is moving in an easterly direction relative to the earth. find speed of airplane to relative to earth.

Physics
A tennis player strikes a ball when it is 2.20m above the ground, with a velocity 18.7 m/s at 20 degrees above the horizontal. The net is 5m away horizontally and it is 0.90m high. after 0.37 seconds, what is the direction of the ball with respect to the horizontal?

Physics
the distance of a planet from its sun is 19000000 miles. if there are 29400000 seconds in one orbit, find the speed of the planet in its orbit about the sun. (assume a circular orbit)

Biology
Which of the following is true for the nucleus? A) It has no definite structure B) It is surrounded by membrane C) It is the eukaryotic cell's energy-producing organelle D) It is closely associated with the Golgi apparatus. E) It is always bluish purple in colour

statistics help
Nevermind, thanks for the help!

statistics help
What is SEm??

statistics help
Tests on a Chevy Cobalt incdicate a population mean of 32 mpg and a population standard deviation of 3.5 mpg. You take an SRS (sample random sample) of 10 cars to get a sample mean. What is the probability that your sample mean is greater than 34 mpg? I am not sure how to go ...

Chemistry
3. Choose the hybridization schemes for the following species. (a) AsBr6− sp sp2 sp3 sp3d sp3d2 (b) CSe2 sp sp2 sp3 sp3d sp3d2 (c) PbCl4 sp sp2 sp3 sp3d sp3d2 (d) SeO32− sp sp3 sp2 sp3d sp3d2 (e) BiF5 sp sp2 sp3 sp3d sp3d2

Chemistry
2. Which of the following molecules is/are trigonal pyramidal? N2O NH3 C2H2 SiF4 HN3 HCN SO3 H2S CF4 PF3 H2O BF3 COS O3 SO2 CS2 AsH3

Chemistry
1. [ PF4 ]+ (a) What is the electron-group geometry, according to VSEPR theory? (b) What is the molecular geometry? (c) Is this species polar or nonpolar?

statistics help
The National Association of Realtors estimates that 23% of all homes purchased in 2004 were considered investment properties. If a sample of 800 homes sold in 2004 is obtained what is the probability that AT LEAST 175 home are going to be used as investment property?

statistics help??
Someone flips a coin 50 times and gets 50 heads in a row. You suspect it is a 2 headed coin. Write the null and alternative hypotheses. Use the binomial theorem to get a p-value of getting exactly 50 hears in 50 trials.

statistics
A manufacturer claims that the mean lifetime of its lithium batteries is 1400 hours. A homeowner selects 25 of these batteries and finds the mean lifetime to be 1380 hours with a standard deviation of 80 hours. Test the manufacturers claim. Use alpha = 0.05. Round the test ...

stat
Construct a 90% confidence interval for the population mean. Assume the population has a normal distribution. A same of 15 randomly selected math majors has a grade point average of 2.86 with a standard deviation of 0.78. Round to the nearest hundredth. Answers: a) (2.41,3.42...

statistics
A university dean is interested in determining the proportion of students who receive some sort of financial aid. Rather than examine the records for all students, the dean randomly selects 200 students and finds that 118 of them are receiving financial aid. Use a 95% ...

physics
A 189.4 kg uniform, horizontal beam is hinged at one end and at the other is supported by a cable that is at 37 degrees to the vertical. The beam is 3.85 m long. Calculate the magnitude of the force at the hinge.

math
verify sin0/sin0+cos0=tan0/1+tan0

Chemistry
For a Sc atom in ground electronic state: 1. how many electrons are there in 4s orbitals? 2. how many electrons are there in 3d orbitals? 3. how many electrons are there in 4p orbitals? 4. how many unpaired electrons are there? 5. to what block does Sc belong to in the ...

Chemistry
Consider the 5p orbital of a hydrogen atom. 1. how many different 5p orbitals are there? 2. how many radial nodes are there? 3. how many angular nodes are there? (i.e. how many nodal planes or surfaces, not including radial nodes)

Chemistry
For each of the following experimental conditions determine whether molar mass would be: 1) too high, B) too low or C) unaffected. In each case, /explain/ how this result occurs a) after removing the flask from the water bath, the experimenter cools the flask to room ...

Science
For each of the following experimental conditions determine whether molar mass would be: 1) too high, B) too low or C) unaffected. In each case, explain how this result occurs a) after removing the flask from the water bath, the experimenter cools the flask to room temperature...

Chemistry
For each of the following experimental conditions determine whether molar mass would be: 1) too high, B) too low or C) unaffected. In each case, /explain/ how this result occurs a) after removing the flask from the water bath, the experimenter cools the flask to room ...

Chemistry
For each of the following experimental conditions determine whether molar mass would be: 1) too high, B) too low or C) unaffected. In each case, /explain/ how this result occurs a) after removing the flask from the water bath, the experimenter cools the flask to room ...

Chemistry
This is just a question on my chem lab which is determining the molar mass of a volatile liquid. i don't understand how to answer this question, esp with the reasoning that has to be provided. help for this would greatly be appreciated!

Chemistry
For each of the following experimental conditions determine whether molar mass would be: 1) too high, B) too low or C) unaffected. In each case, /explain/ how this result occurs a) after removing the flask from the water bath, the experimenter cools the flask to room ...

History
What was Harriet Tubman rebelling against?

Physics
Consider a road over a hill where the top is shaped like a circular bump. This circular arc has its center in the hill below. As a 1200 kg car rounds the top of a hill at a speed of 20.0 m/s, it very breifly loses contact with the pavement. What is the radius of this circular ...

Quantitive Analysis
HOw is it .1725b +b

english
Which of the following options best demonstrates sentence fluency? a. The city looked beautiful in that it was lit by the sun while I was walking down the street. b. Walking down the street in the sunshine, the city looked beautiful. c. The city looked beautiful as I was ...

Pre-Calculus
how to make a xy table for the following greatest integer equation when using -1,-2,0,1,2 to plug into x f(x)=2[x], g(x)=[2x], f(x)=-[[x]], and g(x)=[[-x]]

Math

Physical Chemistry
Calculate the difference between H and U when 1 mole of water is boiled at 373 K and 1 atm. The volume of 1 mole of perfect gas at 373 K is 0.03 m3 and the volume of liquid water may be neglected. (1 atm = 105 N m-2) what equations should be used ?

science
(Ans. (a) ∆U = ∆H = 0; q = 1.57KJ, w = −1.57KJ, (b) ∆U = ∆H = 0; q = 1.13KJ, w = −1.13KJ, (c) ∆U = ∆H = 0; q = 0, w = 0.)

MathematicalModels
Please, could you help me with this update? At time zero you enter a short position in a forward contract on 1 share of the stock XYZ at the forward price of 10.00. Moreover, you buy one exotic derivative, with the same maturity as the forward contract, which pays to the ...

probability
2. mean 50, variance 25

PHYSICS
In a power plant the high pressure turbine trips due to an unauthorised valve shutdown. What are a) what is the angular acceleration of the turbine blade? b) what is the distance travelled by a point on the rim of the turbine blade during the acceleration? c) what is the ...

Math
The inverse of a 2x2 matrix is given by: A=[a b A^1=1/ad-bc[d -b c d]. -c a]. If these two multiplied by each other gives the "identity matrix": [1 0 0 1]. then the inverse exists.

math
x=number of mystery books. 3x=total number of books on the shelf. x/5<10<x/4 is given. Get rid of the fifths and quarters by multiplying by 20. 4x<200<5x --> 40<x<50. The number of mystery books is anything between 40 and 50, multiply by 3 and you have ...

PHYSICS
A dock worker is loading a 25 kg solid cylindrical barrel to a ship by rolling it up a 9 meter long and 1.5 meter high ramp. At the top of the ramp the dock worker stop to go around the barrel but he loses the grip and the barrel starts to roll down the ramp without slipping ...

Algebra
x=4 gives inclination=k=1 in y=kx+m. It also states that m=4. y=x+4

PHYSICS
273.15°K is 0°C. Go from there to 232°C and its where tin melts. Conversion from °C to °K °K = °C + 273.15

Art
Ms.sue really

chemisty
The initial concentration of NO2 in a closed container is 0.750M. At equilibrium the concentration of O2 is 0.125M. What are the concentrations of NO2 and NO at equilibrium? 2NO2 (aq) ==== 2NO (aq) + O2 (aq)

chemistry
The equilibrium concentration of NOCl = {0.0610}, NO = [0.0151, and Cl= [0.0142, what is the value of the equilibrium constant? Don't really get how to figure this out..anyone know? Thanks!!

Physics
you are wrong

chemistry
The density of acetonitrile, CH3CN, is 0.786 g/mL, and the density of methanol, CH3OH, is 0.791 g/mL. A solution is made by dissolving 15.0 g of methanol in 250.0 mL of acetonitrile. Assuming that the volumes of the solute and solvent are additive, what is the molarity of ...

chemistry
The Henry's law constant for CO2 is 3.1 x 10-2 mol/L-atm at 25°C. What pressure would be necessary in order to have a .25 M solution?

chemistry
The Henry’s Law constant for N2 in water at 30 oC is 6.0 x 10-4 M/atm, calculate the solubility of nitrogen gas in water at a partial pressure of 2.5 atm

physics
One particle has a mass of 2.86 x 10-3 kg and a charge of +7.32 μC. A second particle has a mass of 6.41 x 10-3 kg and the same charge. The two particles are initially held in place and then released. The particles fly apart, and when the separation between them is 0.127 ...

physics
A particle of charge +18.1C and mass 7.06 × 10-5 kg is released from rest in a region where there is a constant electric field of +414 N/C. What is the displacement of the particle after a time of 3.06 × 10-2 s? Please explain the steps, thank you.

physics
Two geological field teams are working in a remote area. A global positioning system (GPS) tracker at their base camp shows the location of the first team as 43 km away, 23° north of west, and the second team as 29 km away, 33° east of north. When the first team uses ...

lauric acid
what happens to the calculated molar has if the lauric acid is spilled before determining the freezing point?

caculus
47

Algebra 2
3.4e^2-2n - 9 = -4

physics
Due to a tune-up, the efficiency of an automobile engine increases by 4.00%. For an input heat of 1530 J, how much more work does the engine produce after the tune-up than before?

physics
The internal energy of a system changes because the system gains 180 J of heat and performs 338 J of work. In returning to its initial state, the system loses 111 J of heat. During this return process, what work is involved? If the work is done by the system, then give the ...

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