Wednesday
November 26, 2014

Posts by sierra


Total # Posts: 218

chemistry
That's very helpful! Thank you!
November 24, 2014

chemistry
I just need a definitive answer because I've searched everywhere and it's made me second guess my original answer. How many valence electrons does copper have? I thought it was one but now I'm unsure. I know it's electron configuration is [Ar]4s1 3d10, so that...
November 24, 2014

chemistry
Because I had to convert kJ to J So I did: 1312200/2(6.022x10^23) 6.626x10^-34(3x10^8)/ans and then that answerx 10^9 to convert to nm Where did I go wrong because that answer wasn't correct =(
November 18, 2014

chemistry
Ok that's what I thought! So my answer should be 182.45 nm, yes?
November 18, 2014

chemistry
Wait, what's planck's equation??
November 18, 2014

chemistry
Experimentally the ionization energy of hydrogen is 1312.2 kJ / mol. What would be the wavelength (nm) of a photon with enough energy to ionize one atom of hydrogen? They give the equation E=hcR but those are all known constant values and none include mols so I'm very ...
November 18, 2014

History
What are some aspects of the modern American political party system that began during the Jackson era? A.beginnings of political action committees and fundraising B.widespread campaigns for the popular vote, including fliers, slogans, and songs C.of campaign tours and town ...
November 10, 2014

chemistry
Hemoglobin is the oxygen carrying molecule of red bloods and contains 4 atoms of iron per molecule of hemoglobin. A sample of hemoglobin weighing 13.4 g contains 45.6 mg iron. What is the molecular mass of hemoglobin? I'm unsure of where to begin with this problem. I know ...
October 24, 2014

COLLEGE PHYSICS
7500J=1/2(M2V^2) +1/2(1.5M2)(V^2) 7500J=1/2 (M2V^2+1.5M2V^2) 15000=M2V^2+1.5M2V^2 15000= X+1.5X 15000=X(2.5) 6000=X 6000 = X = M2V^2 1/2(6000) = KE 3000 = KE TOTAL PE (7500J) - KElargerobject(3000) = 4500J (KE smaller object)
October 22, 2014

COLLEGE PHYSICS
7500J = KE1 + KE2
October 22, 2014

physics
A circular curve of highway is designed for traffic moving at 93 km/h. Assume the traffic consists of cars without negative lift. (a) If the radius of the curve is 110 m, what is the correct angle of banking of the road? (b) If the curve were not banked, what would be the ...
October 7, 2014

religion
who do members of the Jesuit Volunteer Corps work for?I need help,been stuck on this question for,like,15 minutes,I've been searching the internet for 20 minutes.
September 28, 2014

chemistry
In 26. The reaction is Br- + H3O+ = HBr + H2O. Not Br- + H3O+ = HBr = H2O! Im sorry!
September 16, 2014

chemistry
25. Which of the two reactions, A or B is a neutralization reaction? Explain why. A. HBr + H2O = Br- = H3O+ B. HClO + NaOH = NaClO + H2O 26. A. Look at the reaction again. when this reaction is reversed. Br- + H3O+ = HBr = H2O what substance is the acid, what is the base. B. ...
September 16, 2014

chemistry
Please identify the acid and the base in this equation. HClO + NaOH = NaClO + H2O Thank you!
September 15, 2014

History
The third one would be Serbia.
September 15, 2014

Chem
41. How much heat energy must you use to raise the temperature of 100 grams of water from 60C to 70C. Show your calculations. 42. You have a pot of 100C liquid water. If you add heat to the water, will the temperature start to raise at once? why or why not. Thank you for your ...
September 15, 2014

Social Studies
The answer is B because, she is creating and selling something herself.
September 15, 2014

Chemistry: Please Help!!
39. Explain why sweating cools you down in terms of molecular kinetic energy. 40. You take a pizza out of the oven and let it cool briefly. When you bite into it, the crust is not too hot but the cheese burns your mouth. Explain why this happens in terms of specific heat ...
September 15, 2014

Chemistry: Please Help!!
37. Lake Michigan is a very large, very deep body of water, located in a region of the United States that gets quite cold in winter. On the coldest day of last year, what was the temperature at the bottom of the lake. Explain your answer in terms of density of water. 38. ...
September 15, 2014

Chemistry
B. Could non-polar nitrogen molecules and polar water molecules form bonds with one another? if so, what kind? C. Given your answer to B above, do you think that there is a great deal of N2 dissolved in the oceans, a small amount, or none at all?
September 15, 2014

Earth Science
D. Epicenter.
September 15, 2014

math
3/4 of a gallon is 6/7 of the amount originally in the container. how much was in container originally
April 20, 2014

social studies
where did major general William Rufus Shafter stay while he controlled the war? PLEASE HELP!!!!!!
April 7, 2014

Math
In triangle ABC, m<A=71, m<C=41, and BC=96. To the nearest tenth, what is AB?
March 27, 2014

Math
Write a rule in function notation to describe transformation that is a reflection across the x-axis. A. Ry-x(X,Y) B. Rx-0(X,Y) C. Rx-y(X,Y) D. Ry-0(X,Y)
March 27, 2014

Geometry
The vertices of a triangle are P(-3,8), Q(-6, -4), and R (1, 1). Name the vertices of R (smaller letters)y-0 (triangle PQR). A. P'(-3, 8), Q'(-6,-4), R'(1,1) B. P'(-3,-8), Q'(-6,4), R'(1,-1) C. P'(3,-8), Q'(6,4), R'(-1,-1) D. P' (3,8), Q...
March 26, 2014

Algebra
6/z-3=8/5 help please.
March 21, 2014

Math
Line LM is the mid-segment of rectangle ABCD. AB=x+8, LM = 4x+3, and DC=243. What is the value of x?
March 11, 2014

Math
Line LM is the mid-segment of rectangle ABCD. AB=72 and DC=104. What is LM? A.176 b. 88 c.98 d.32
March 11, 2014

Math
In the rhombus, angle 1=15x, angle 2=x+y, and angle 3=30z. Find the value of each variable.
March 10, 2014

Math
Line DF bisects angle EDG. Find the value of x. Line EF has 9x+114. Line FO has 15x. angle FDG has 32 degrees.
March 10, 2014

Geometry
What is an equation in point-slope form for the line perpendicular to y=2x+13 that contains (8,-4)?
March 9, 2014

Social Studies 10
"Was the conflict over the Red River Settlement inevitable? Provide reasons for your answer." <- exact
March 6, 2014

Math
Can you please check my answers? Thank you! 18 out of 25 people love chocolate what percentage of people do not love chocolate? I got 28% 15% of the Chemistry class did not pass their chapter 7 test if the class has 38 students how many students did not pass their chapter 7 ...
November 4, 2013

math
How do I simplify -(5x+5)-4+8x
October 22, 2013

math
How do I simplify -9-(12-3x)
October 22, 2013

us history
Which of the following is true of the Spanish-American War? A. Racial tensions were suspended for the duration of the war. B. About one in ten American soldiers were black. C. Black soldiers referred to black Cubans as "Smoked Spaniards." D. The black soldiers who ...
October 1, 2013

English 11A
i need to write a story for English and i have to use seven comma rules along with my 20 vocabulary words. abomination blanched conjure contentious contiguous corroborate dally defamation enthrall evasive imperceptible inaudible inquisition licentious prodigious quavering ...
September 16, 2013

Physics
thank you for your help
August 22, 2013

Physics
Electrons on a radio broadcasting tower are forced to oscillate up and down an antenna 535,000 times each second. Show that the wavelength of the radio waves that are produced is 561 m.
August 22, 2013

math
I say tues at 1am
April 30, 2013

Physics, help!
A heat engine absorbs 126 kcal of heat and exhausts 77 kcal of heat in each cycle. Calculate the efficiency (as a percentage) An ideal gas heat engine operates in a Carnot Cycle between temperatures of 266 and 115°C. It absorbs 4250 cal per cycle at 266°C. What is its...
January 18, 2013

Help me! Physics
A block of aluminum with a mass of 2.6 kg is at 13C and comes in contact with a hot block of copper with a mass of 10.2 kg at 93C. What is the equilibrium temperature in Celsius degrees? caluminum = 0.22 kcal/kgC ccopper = 0.093 kcal/kgC
January 17, 2013

Math
The Commplement of angle v 52 more than angle v. find the measure of angle v.
January 9, 2013

Pre-Algebra
2x = 3(1/3x + 6) 2x = x + 18 x = 18
January 7, 2013

Physics-Momentum
Baseball 0.14 kg moving at 35 m/s. Momentum of the ball? this should be easy b/c i know p=m*v but i get 4.9 kgm/s and it's wrong.....
January 7, 2013

Please I'm begging someone help me with biology
Thank you so much for your help I really need to know that
December 13, 2012

Please I'm begging someone help me with biology
I need help with listing two ways that single - celled fungi are different from bac-terial cells??? I'm so clueless I'm begging anyone to help me thanks
December 13, 2012

Please I'm begging someone help me with biology
I need help with listing two ways that single - celled fungi are different from bac-terial cells??? I'm so clueless I'm begging anyone to help me thanks
December 13, 2012

math 6th grade proportions
Sorry if I may be bugging you,but this homework is veryy hard for me!Karen gets 6 out of every 8 questions on a test correct.If she gets 27 questions correct,how many questions are on the test?
December 10, 2012

math 6th grade proportions
Thank-you!! :)
December 10, 2012

math 6th grade proportions
Hello,Umm I need Alot of help on this problem:Emma runs for 18 minutes out of the 45 minutes she spends exercising each morning.One morning she spends 70 minutes exercising.If her rates stay the same how many minutes will she spent running>PLEASE HELP A.S.A.P!!!!!!!!
December 10, 2012

math
Laura has 4 CDS in her room. They are 1/5 of her whole collection. How many CDs are in Laura's whole collection?
December 10, 2012

Physics ASAP
A block of weight 20 N is pushed with a force of 30 N through a horizontal distance of 5 m using a stick which is at an angle of 37° from the horizontal as shown. The coefficient of kinetic friction µk between the table and the block is 0.25. For your own reference, ...
December 10, 2012

math
write a number and a fraction greater than 1 that name the part filled
December 5, 2012

history
8. The Puritan _______ became the governor of the Massachusetts Bay Colony.
December 3, 2012

Geology
Which of the three rock families occurs most in new York state?
November 27, 2012

Geology
What observable characteristic is present with banding of metamorphic rocks that is not present in the layering of clastic sedimentary rocks?
November 27, 2012

Physics
A cylindrical carnival ride is spinning with a frequency of 0.5 Hz in a circle of radius 3 m which allows a 60 kg person to “stick” to the side of the ride as it spins. T = 2s v = 9.42 m/s A) Find the normal force exerted on the person. B) What minimum µs is ...
November 27, 2012

Physics Please Help ASAP
thank you so much! super helpful i didn't realize i was overlooking the radius of earth!
November 26, 2012

Physics Please Help ASAP
Suppose the space shuttle is in orbit 390 km from the Earth's surface, and circles the Earth about once every 92.4 minutes. Find the centripetal acceleration of the space shuttle in its orbit. Express your answer in terms of g, the gravitational acceleration at the Earth&#...
November 26, 2012

physics
there's no question, just a bunch of information about the situation
November 26, 2012

Physics ASAP
Suppose the space shuttle is in orbit 390 km from the Earth's surface, and circles the Earth about once every 92.4 minutes. Find the centripetal acceleration of the space shuttle in its orbit. Express your answer in terms of g, the gravitational acceleration at the Earth&#...
November 26, 2012

Physics ASAP
Use the following numbers for this question. MEarth 5.98e+24 kg MJupiter 1.9e+27 kg MSun 2e+30 kg Earth-Sun distance 150000000000 m Jupiter-Sun distance 778000000000 m rE 6380000 m rJ 69000000 m G = 6.67e-11 Nm2kg-2 the acceleration due to gravity at the surface of Jupiter has...
November 18, 2012

Trig
Give: a=alpha B=beta csc a= 2 pi/2<a<pi secB=-3 pi/2<B<pi 1)find sin(a+B) 2)find tan(a-B) 3)cos B/2 4)sin a/2
November 7, 2012

trig
How do you find the exact value of sin 5pi/8?
November 7, 2012

Physics
a quaterback throws a ball to a stationary reciver wo is 15.2m down the feild. the football is thrown at an initial angle of 42 dagrees. acceleration is 9.81m/s^2. what is the initial speed that quaterback must throw the ball to hit the reciver?
October 23, 2012

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 ...
October 1, 2012

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.
October 1, 2012

physical science
what is the density of a peice of wood that has a mass of 25.0 grams and a volume of 29.4cm cubes?
September 13, 2012

math
would you use perimeter or area to find the quanity of track needed for a tabletop railroad
August 22, 2012

Physics
A snake is sunning itself on a rock. (a) If the snake is 0.5 m long, what is the approximate amount of radiation it absorbs from the Sun in 11 min? (Assume the snake has a cylindrical shape and ignore both ends, a radius of 0.03 m, and a mass of 2.1 kg. Assume also that the ...
July 31, 2012

Physics
The intensity of sunlight at the the top of the Earth's atmosphere is about 1350 W/m2. (The intensity at the surface of the Earth is somewhat smaller due to absorption and reflection by the atmosphere.) What is the total power emitted by the Sun?
July 31, 2012

Physics
Use the exact values you enter in previous answer(s) to make later calculation(s). Energy-efficient windows are constructed with two panes of glass separated by an air gap (see figure below). In a typical window of this type, the air gap makes a huge difference in the rate of ...
July 31, 2012

Physics
A rectangular aluminum plate has an area of 0.41 m2 at 23°C. If it is heated until its area has increased by 4.4 10-6 m2, what is the final temperature of the plate? °C
July 31, 2012

Physics
Your swimming pool is square and 4.9 m on a side. It is 3.9 m deep in the morning. If the temperature changes by 44°C during the afternoon, how much does the depth of the water increase?
July 31, 2012

Physics
If you combine 34 kg of ice at 0°C with 80 kg of steam at 100°C, what is the final temperature of the system? °C
July 31, 2012

Physics
You drop 378 g of solid ice at −35°C into a bucket of water (1,200 g) at 45°C. Eventually, the ice all melts, and the entire system comes into thermal equilibrium. Find the final temperature of the system.
July 31, 2012

Physics
An ice cube of volume 17.7 cm3 is initially at a temperature of -19.3°C. How much heat is required to convert this ice cube into steam?
July 31, 2012

Physics
How much heat is required to raise the temperature of a 4.3-kg block of steel by 48 K? (The specific heat of this steel is 450 J/kg · K.)
July 31, 2012

Physics
A tank of water sits at the edge of a table of height 1.4 m. The tank springs a very small leak at its base, and water sprays out a distance of 1.2 m from the edge of the table. What is the water level h in the tank? (Assume the tank is open to the air at the top.)
July 25, 2012

Physics
Water is flowing through a pipe (area 4.0 cm2) that connects to a faucet adjusted to have an opening of 0.57 cm2. If the water is flowing at a speed of 5.3 m/s in the pipe, how long does it take for water from the faucet to fill a bucket of volume 0.11 m3?
July 25, 2012

Physics
Two metal blocks are attached by a cable as shown in the figure below and are submerged at rest near the surface of a lake. If the volumes are V1 = 2.1 m3 and V2 = 1.1 m3, what is the total buoyant force on the two blocks?
July 25, 2012

Physics
You want to design a helium-filled balloon that will lift a total payload of 1225 kg. What volume of helium is needed to just barely lift this payload?
July 25, 2012

Physics
A block of mass 20 g sits at rest on a plate that is at the top of the fluid on one side of a U-tube as shown below. The U-tube contains two different fluids with densities ρ1 = 965 kg/m3 and ρ2 = 550 kg/m3 and has a cross sectional area A = 5.5 10-4 m2. The surfaces...
July 25, 2012

Physics
A syringe has an area of 1.4 cm2 at its barrel and then narrows down to an area of 0.08 mm2 at the needle end. If a force of 5.5 N is applied to the syringe, what is the force produced at the tip of the needle?
July 25, 2012

Physics
A bucket is filled with a combination of water (density 1,000 kg/m3) and oil (density 700 kg/m3). These fluids do not mix. (The oil will float on top of the water.) If the layer of oil is 63 cm tall, what is the pressure at the interface between the oil and the water?
July 25, 2012

Physics
A U-tube contains two fluids with densities ρ1 = 1070 kg/m3 and ρ2 = 595 kg/m3 as sketched below. What is the difference d in the heights of the top surfaces of the two fluids?
July 25, 2012

Microbiology
What responsibilities do patents have for their children's health?
July 15, 2012

trig
Solve the equation on the interval [0,360) cos^2t+2cos(t)+1=0
July 12, 2012

trig
Find all solutions in the interval [0,360) sin(4t)=ã3/2
July 12, 2012

Physics
Nothing
July 11, 2012

physics
You are pushing a refrigerator across the floor of your kitchen. You exert a horizontal force of 273 N for 7.2 s, during which time the refrigerator moves a distance of 3.4 m at constant velocity.
July 11, 2012

Physics
A rock of mass 0.086 kg is thrown upward with an initial speed of 13 m/s. Find the work done by gravity on the rock from the time it leaves the thrower's hand until it reaches the highest point on its trajectory. Hint: You do not have to calculate the rock's maximum ...
July 11, 2012

Physics
A car of mass 1,700 kg is initially traveling at a speed of 25 m/s. The driver then accelerates to a speed of 35 m/s over a distance of 500 m. Calculate the change in the kinetic energy of the car.
July 11, 2012

Physics
A car of mass 1,700 kg is initially traveling at a speed of 25 m/s. The driver then accelerates to a speed of 35 m/s over a distance of 500 m. Calculate the change in the kinetic energy of the car.
July 11, 2012

Physics
A block of mass is pulled along a rough horizontal surface by a rope as sketched in the figure below. The tension in the rope is 45 N, and the coefficient of kinetic friction between the block and the surface is
July 11, 2012

Physics
A crate of mass 29 kg is pushed up a ramp by a person as shown in the figure below. The person pushes the crate a distance of 25 m as measured along the ramp. Assume the crate moves at constant velocity. Assume the coefficient of kinetic friction between the crate and the ramp...
July 11, 2012

Physics
A crate of mass 59 kg is pushed across a level floor by a person. If the person exerts a force of 30 N in the horizontal direction and moves the crate a distance of 12 m, what is the work done by the person?
July 11, 2012

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