# Posts by katie

Total # Posts: 2,141

Chemistry (Electrons in Atoms)
The wavelength of visible light varies from 0.40 μm to 0.70 μm as the color of the light changes from violet to red. Calculate the energy of a photon whose wavelength is 0.67 μm HINT: From the wavelength and the speed of light, we can get the frequency. Then the...

Chemistry (Electrons in Atoms)

Chemistry (Electrons in Atoms)
What is the wavelength of the emitted photon, when the electron in the hydrogen atom makes a transition from the ni = 5 state to the nf = 3 state?

Civics (The American President Movie)
In the movie the American Dream President Andrew Shepard (Michael Douglas) shows the roles of the President. What are examples of him being 1. Chief of State 2. Chief Executive 3. Chief Adminstrator 4. Chief Diplomat 5. Commander in Chief 6. Chief Legislator 7. Chief of Party ...

Physics

Physics
How long will it take a charged 80-ìF capacitor to lose 20 percent of its initial energy when it is allowed to discharge through a 45 ohm resistor?

physics
Resistance in a Series Circuit lab: Determine the coded value of your resistors. (I found 270 ohms, 560 ohms and 750 ohms) ***Enter the toleranace value as indicated by the color of the fourth band. (all were gold) How do I find TOLERANCE VALUE of the gold band??? Thank you.

physics
three resistors of 10, 15, and 20 ohms are connected in parallel to a source of current. In which resistor is the current greatest How do I set this up?

exp in math
I see where I made a mistake thanks!

exp in math
convert 110010 to base 10 2 I'm not sure about this one is it 60 or 62 I did all the steps, but it seems like I'm still missing something

exp in math
convert 1100 two to base 10 I came up with 1100 2 = 12 is this correct?

explorations in math
the question reads covert the numeral to a numeral in base 10 2068 12

explorations in math
covert 2068 twelve to base 10

explorations in math
4.5 + 1.1 20 + 1 21

explorations in math
convert the numeral to a numeral in base 10 14 5

Math
1) use the M method to solve the following linear programming problem: Minimize C+ -5x+10x+15x Subject to 2x+3x+x <(or equal to) 24 x-2x-2x >(or equal to) 1 x,,x,x>(and equal to) 0

Chemistry
A solution contains an unknown amount of dissolved calcium . Addition of 0.112 mole of K3PO4 causes complete precipitation of all the calcium. How many moles of calcium were dissolved in the solution?

Chemistry
A solution contains 0.133 g of dissolved Lead. How many moles of soduim chloride must be added to the solution to completly precipitate all of the disolved lead? What mass of sodium chloride must be added?

Calculus
Give the domain of each of the functions listed below : a) f(x)= ln (tanh^-1 (x)) b) g(x) = cos ^-1 (e^x) I just don't know how to set them up to solve for x ...I'm doing a Calc course online on my own, and would really appreciate the help :) Thanks

Math
The nominal rate of interest is 8% and the rate of inflation is 5%. A single deposit is invested for 10 years. Let: A= value of the investment at the end of 10 years measured in "constant dollars," i.e. in dollars valued at time 0. B= value of the investment at the ...

Chemistry
1% glucose = hemolysis 2% NaCl = crenation 5% NaCl = crenation .1% NaCl = hemolysis

Physics
A 180 kg object is taken to a height of 350 km above the Earth's surface. The object's mass of height is 180 kg. What is the object's weight at this height?

Art Appreciated
Discuss how the Late Gothic sense can be seen as an evident in Berlinghieri's St. Francis Altarpiece.

geometry
how do I find the measurement of the hypotenuse side of a triangle when the other side measurements are 5 and 12

physics
Electrons flow from a ___ potential to a ___ potential.

physics
Find the cross-sectional area of copper wire that is 55.4 m long and has a resistance of 0.943 ohms. The resistivity of copper is 1.79 x 10^-8 ohms m.

Chemistry
You have a reaction using the following criteria: 1.3456 g of barium chloride solution (0.786M) is mixed with 1.20089 g of sodium sulfate solution (1.3M). The ambient pressure is 754.564 mmHg and the temperature is 56.889 degrees celsius. Determine the volume of the gas produced.

Statistics
TRUE OR FALSE: For a set of data with mean 6 and variance 16, approximately 68% of the values will fall between -2 to 14.

English
I need help analyzing this poem please Seasonal Anxiety Spring never felt like a beginning— Something, perhaps, to do with school And all the school-year's slow unspinning From wound-up time as from a spool Aimed at Summer's golden rule. Beginnings are for autumn ...

PHYSICS
Sally Sue, an enthusiastic physics student enjoyed the opportunity to collect data from standing waves in a spring. She and her partner help the ends of their spring 4.00 meters apart. There are 5 nodes in the standing wave produced. Sally moved her hand from the rest position...

Math 9
2 extension ladders are leaning at the same angle against a vertical wall. The 3 meter ladder reaches 2.4 meters up the wall. How much farther up the wall does the 8 meter ladder reach?

Prime Minister
nuclear power generation is like the plants in Japan that are causing so much trouble. If it was me, i would suggest to keep the exisiting plants we have now, and upgrade their saftey levels and back up power sources. And, in the future, if we as a country, build more, they ...

science
This disease starts in infancy and usually results in death by the age of 4 years.

Biology
Try this link and see if it helps you any. the human genome project in google.

statistics
Let x be a continuous random variable that is normally distributed with a mean of 24 and a standard deviation of 7. Find the probability that x assumes a value between 27.5 and 59.0. Use Table IV in Appendix C to compute the probabilities. Round your answer to four decimal ...

statistics
Let x be a continuous random variable that is normally distributed with a mean of 65 and a standard deviation of 15. Find the probability that x assumes a value less than 45.

statistics
Find the area between x = 9.5 and x = 23 under a normal distribution curve with μ = 20 and σ = 4 .

statistics
Let x be a continuous random variable that is normally distributed with a mean of 65 and a standard deviation of 15. Find the probability that x assumes a value less than 44.

Find the sum of the angle in each regular polygon. (Pentagon)

physics
Using fn = (nv)/(2L) and plugging in values as fn = f6 = 557.14 = (6v)/(2*0.7) and solving for v, we get v = 130 m/s.

physics
Using fn = (nv)/(2L) and plugging in values as fn = f6 = 557.14 = (6v)/(2*0.7) and solving for v, we get v = 130 m/s.

physics
Prolonged exposure to sounds of intensities lower than the threshold of pain can also damage the ear. This is more dangerous since there is no pain to warn the victims about the ear damage and they can end up damaging their ears unknowingly through prolonged exposure to such ...

physics
(A) When only one end is open, it is a 'closed' pipe and so we use Where fn = frequency of nth harmonic (Hz) n = harmonic number v = speed of sound inside the pipe (m/s) L = length of pipe closed at one end (m) Plugging in the values and solving, we get f1 = 428.75 Hz ...

Did I answer these correctly? ¿Qué necesitas para jugar al tenis? Necesito una raqueta y una pelota de tenis para jugar al tenis. ¿Cuándo juegas el ajedrez? Yo juego el ajedrez por la noche.

physics help
I need help confirming my answers: 1) The work done on an electric charge equals a) IR b)q/t c)Vq d) It I think it's C.(Vq) 2) The direction of an electric field is the direction that a ___ test charge will move when placed in the field. a)negative b) positive c) neutral I...

biomechanics
If a soccor ball with a mass of 0.43 kg is kicked while it is in the air, with a force of 15 N oriented 32 degrees above the horizontal, what is the resultant acceleration?

physics
I need help confirming my answers: 1) The work done on an electric charge equals a) IR b)q/t c)Vq d) It I think it's C.(Vq) 2) The direction of an electric field is the direction that a ___ test charge will move when placed in the field. a)negative b) positive c) neutral I...

Chemistry
All of those are separate reactions that are being reacted with 50 mL of 1.50 M NH3.

Chemistry
How do you calculate the volumes of the acid solutions (1.50M HCl, 1.50M HNO3, and 1.50 M H2SO4?

Math
A circular garden has an area of 25π m2 If the . radius is increased by two meters, and fencing is sold only in one meter sections, how much fencing is needed to keep out the rabbits

Chemistry
Sorry my computer accidentally resent it!

Chemistry
Is a calibrated thermometer more precise than one that has not been calibrated? What implications does this have for measuring temperature changes as contrasted with measuring individual temperatures?

Chemistry
Is a calibrated thermometer more precise than one that has not been calibrated? What implications does this have for measuring temperature changes as contrasted with measuring individual temperatures?

MATH
Method 1 Simply list the multiples of each number (multiply by 2, 3, 4, etc.) then look for the smallest number that appears in each list. Example: Find the least common multiple for 5, 6, and 15. First we list the multiples of each number. Multiples of 5 are 10, 15, 20, 25, ...

chemistry
A scientist wants to make a solution of tribasic sodium phosphate, \rm Na_3PO_4, for a laboratory experiment. How many grams of \rm Na_3PO_4 will be needed to produce 250 mL of a solution that has a concentration of \rm Na^+ ions of 0.600 \it M?

Chemistry
Would you use q/mass*change in T= c so 1930J/(500g*10degC)=.386J/degC?

Chemistry
An unknown material absorbs 1,930 J of heat when it changes from 25 °C to 35°C. The sample weighs 500g. What is the specific heat of this material?

Math
After the first 41 games of the baseball season, the Red Sox have a winning percentage of 0.585 and the Yankees have 0.512. How many games behind the Red Sox are the Yankees?

math
so there be 25 green, 15 blue, 10 red???

math
TODAY

chemistry
write an equilibrium constant expression for the reaction of acetylene gas with hydrogen gas to produce methane gas.

algebra
A set of 2 similar triangles was drawn in a design. One of the triangles was ½ of the other. If the measures of the smaller triangle were 5, 7, and 12 cm, the measures of the larger triangle = 10,14 and 20 cm. true or false

Geometry quick i have test tomorrow
what is the length of any diagonal of a regular pentagon with a side of 20mm

geometry
what is the length of any diagonal of a regular pentagon with a side of 20mm ?

Chemistry
How do i determine the exact molarity of .2 M of HCL? The molarity of NaOH Used was .2010M used in the titration. And the volume used 10.33 mL used to reach equivalence point. What would be the Molarity of HCL?

math
if less then a half of a garden is planted with corn is it a reasonable to estimate that 2-3rds of the garden is planted with corn?

chemistry
If 74.5 grams of a hot metal was added to 56.4 grams of water and the temperature of the water rose from 20.4 to 33.4 degrees, how many KJ of energy was lost by the hot metal? i need helping setting up where the numbers go. I'm lost

chemistry
i need help setting this problem up. i don't understand which numbers go where

chemistry
If 74.5 grams of a hot metal was added to 56.4 grams of water and the temperature of the water rose from 20.4 to 33.4 degrees, how many KJ of energy was lost by the hot metal?

Differential equation- Math
Find the general solution of the following system of equation? Please help, i don't know what to do... dx/dt = 3x +2y +2z dy/dt = -5x - 4y - 2z dz/dt = 5x + 5y +3z.

amet
substituting t=12s gives a = 2(12) - 10 = 14m/s-2 Using the formula d = Vit +1/2 at^2 d = 15(12) + 0.5 (14)12^2 d = 180 + 1008 d = 1188 meters (distance traveled) add the initial position d = 1188 + 1.8 = 1189.8 (Position of particle) I hope this is correct... :(

social studies
it say to briefly describe the events that followed the Confederate defeat at Gettysburg. (civil war). first is followed meaning before or after. and what does it mean by describe the events?

science
How do you calculate the atomic mass of magnesium? 79% magnesium-24, 10% magnesium-25, 11% magnesium-26

algebra
Tammy bought 16 cookies for a party. She had 6 cookies decorated at an extra cost of 25 cents each. If the total cost of the cookies was \$9.50, how much did each plain cookie cost?

Science
What is the initial temperature? If it is just for phase change then the formula is Q = m L Q = 0.063 x 32.3

Science
Calculate the amount of heat required to completely sublime 63.0 g of solid dry ice CO2 at its sublimation temperature. The heat of sublimation for carbon dioxide is 32.3 C.

Science
Calculate the amount of heat required to completely sublime 63.0 g of solid dry ice CO2 at its sublimation temperature. The heat of sublimation for carbon dioxide is 32.3 C.

Chemistry
What is the change in internal energy of a system that releases 1275 J of heat to the surroundings and is compressed so that 235 J of work are done on the system?

english
thankyou so much that is so helpful

english
Im not sure on how to do my introduction on an essay for a school magazine giving your views on how people treat animals? can someone please help me thanks alot

Geography/History
sorry i was saying katilin

ENG
Choose the correct verb: Some people (know, Knows) more about their favorite TV characters than they do about the members of their own family. A) knows B) know

chemistry
A 6.0 L flask contains a mixture of methane, argon and helium at 45 degrees C and 1.75 am. If the mole fractions of helium and argon are 0.25 and 0.35, respectively, how many molecules of methane are present?

Math
The number of calls received by a car towing service averages 14.4 per day (per 24 hour period). After finding the mean number of calls per hour, find the probability that in a randomly selected hour the number of calls is 0

calculus
let f(x)=sqrt x+4. Calculate the difference quotient f(5+h)-f(5)/h for h=.1 h=.01 h=-.01 h=-.1

PRE-ALGEBRA
2V/5+V/4

Calculus
A retangular poster is to be made out of cardboard. The margins on the top and the bottom will be 2 inches. The margins on the sides will be 1 inch. The area of the poster devoted to the printed material must be 300 square inches. (a) to the nearest .001 inches, find the ...

algebra1
how do you slove x+3y=-30 9x-12y=3 with substitution and elimation

How many possible combinations for an 8-digit binary number are there? How did you get this an answer?

Chemistry
A square of aluminum foil measuring 3.20 inches on each side weighs 275 mg. The density of aluminum is 2.70 g/cm3. Find the thickness (in micrometers) of the foil.

algebra 2
find the average rate of change for the function f(x)=60x-3x^2 between x=6 and x=19

Science fair projets with fish

english
where did the jim crow laws take place? and why?

Calculus
The shape is a cone. The radius is 6 cm and the height is 9 cm

Calculus
If water is poured into a cup at a rate of 1 cubic centimeter per second, how fast is the dept of the water increasing when the water is 4 cm deep? r = 6 cm h = 9 cm V = 1/3(pie) r^2 x h V = (pie)r'h + 1/3 (pie)r^2 h' 6 / 9 = r / h 6h = 9r r = 3 / 4.5 h V = 1/3(pie) (3...

Calculus
Okay, I see what I did wrong. I did dy/dt = 6 instead of dy/dt = .5. Thanks a lot

Calculus
A street light is hung 18 ft. above street level. A 6-foot tall man standing directly under the light walks away at a rate of 3 ft/sec. How fast is the tip of the man's shadow moving? I know I would've to set up a proportion. 18 / 6 = x + y / y x = distance of man from...

Calculus
Two trucks start from the same point. One truck travels due east at a rate of 50 mph and the other trucks travels due north at a rate of 60 mph. At what rate is the distance between the two vehicles increasing 1 1/2 hours later? I think the answer is 55 mph because I added 60...

Calculus
The slope is actually -5. And forget I think i understand this now.

Calculus
In the diagram below, the y-coordinate of point P is increasing at a rate of 4 units per minute while point Q remains in its fixed position. Find the rate of change of angle, in radians per minute, when y = 20. y ^ | P (0, y) | | | | |---| |___|________ Q (4, 0) Then, P (0 , ...

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