Friday

May 6, 2016
Total # Posts: 1,108

**chemistry **

What is the percent yield for the reaction PCl3(g) + Cl2(g) --> PCl5(g) if 119.3 g of PCl5 are formed when 61.3 g of Cl2 react with excess PCl3? I don't understand how to set this up?
*July 13, 2011*

**chemistry**

iron(III) oxide reacts with carbon monoxide gas to form solid iron metal and carbon dioxide gas: Fe2O3 + 3 CO --> 2 Fe + 3 CO2 If you begin the reaction with 84.34 g of iron(III) oxide and 68.87 g of CO, which reactant will be in excess at the end of the reaction and how ...
*July 12, 2011*

**Public health**

monitoring of reports of communicable diseases in the community types: descriptive and analytic epidemiology is used to determine such
*June 28, 2011*

**chemistry**

How many grams of O2 are required to burn 46.0 grams of C5H12?
*June 22, 2011*

**history**

Describe how influential the Cold War has been on the world of today.
*June 11, 2011*

**math**

Block method: 8 teachers for 5 courses [#]*[#]*[#].... [8]*[7]*[6]*[5]*[4]= ?
*June 7, 2011*

**Statistics**

A bag of marbles has 5 Green, 4 Red, and 3 yellow marbles. Three marbles are randomly drawn from the bag, without replacement: What is the probability that at least one of the three marbles drawn are red? What is the probability that only one of the three marbles drawn is red...
*June 7, 2011*

**MATH please help**

thanks
*June 6, 2011*

**MATH please help**

Out of 42 kids in a class twice as many failed Ela as math,4 failed both. If 7 failed neither, find how many failed each subject. Please help and show work it would be great thanks i really need help thanks
*June 6, 2011*

**Statistics**

Under what circumstances does the sampling distribution of the proportion approximately follow the normal distribution?
*June 3, 2011*

**Geometry**

V of cube = side*side*side = 6*6*6 = 216 V of hemisphere = 1/2 of V of sphere = 4/3*pi*radius cubed = 1/2(4/3(pi 3cubed))= 1/2(4/3(pi 27)= 1/2(36pi)= [18pi meters] or [56.52 meters]
*June 1, 2011*

**Science**

Using the balanced equation for this reaction, calculate the volume of CO2 that should be produced by the decomposition of 2.21g of CuCO3•Cu(OH)2 at STP.
*June 1, 2011*

**math**

20+d+10 where d=30, 20+30+10=60minutes or 1 hour
*June 1, 2011*

**Physical Science 2nd Semester**

I hope this answers your question!!
*May 24, 2011*

**world issuse**

I'm a 7 letter word u read daily,my 5th 6th and 7th letter increase each year,my 3rd n 4th letter are the same,my 3rd 2nd n 5th letter cover 75% of the world.
*May 24, 2011*

**english**

Thanx
*May 23, 2011*

**english**

Pls Re-arrange this word aidgact
*May 23, 2011*

**english**

Is incense a social problem and why ?
*May 14, 2011*

**Algebra**

what does the sigma notation look like for the sequence 1/4,-1/9,1/16,-1/25
*May 12, 2011*

**math**

If a a sheet of cardboard measures 9 feet by 6 feet and is made into a perfect cube, what would the length of each edge be?
*May 9, 2011*

**math**

If a a sheet of cardboard measures 9 feet by 6 feet and is made into a perfect cube, what would the length of each edge be?
*May 9, 2011*

**Chemistry**

Calculate the pH of a solution that is made by mixing 10.00 mL of 0.2500 M HCl with 35.00 mL of .1500 M HNO3 and diluting the mixture to a total volume of 100.00 mL
*May 5, 2011*

**Science**

I would recommend to check out a website called physmatixsolve They helped me with a tough question i got in my Physics homework, classical mechanics. The amazing thing is that they really sent me the solution in less than 24 hours, which is pretty neat.
*April 25, 2011*

**Physics**

A 395cm oscillator has a speed of 104.5cm/s when its displacement is 2.80cm and 74.5cm/s when its displacement is 6.60cm. What is the oscillator's maximum speed?
*April 24, 2011*

**Physics**

A 20 cm long, 180g rod is pivoted at one end. A 17g ball of clay is stuck on the other end. What is the period if the rod and clay swing as a pendulum?
*April 24, 2011*

**spelling **

future
*April 20, 2011*

**Math**

Kelly takes 6 laps and Angela takes 5 laps so they both meet at the starting point at 90 minuets...1 hour and 30 minuets.
*April 20, 2011*

**Math**

If angle x lies in quadrant 3 and cos(x)= -0.6 Find cos(3pi/2-x)
*April 20, 2011*

**trig**

angle x lies in quadrant 3 and cos(x)=-.6. Find cos(3pi/2-x)
*April 19, 2011*

**A level english literature**

I need to write an essay comparing estrangement and alienation in cat on a hot tin roof and awakening, I sort of know what to write but I'm struggling to get a good opening to my essay. Help!
*April 19, 2011*

**Physics**

Fresh snow is about one-tenth as dense as liquid water. How much latent heat is released in storm clouds per square kilometer of surface area by the freezing of water droplets if the storm deposits a 30-cm-deep layer of fresh snow? Q = LfM where the mass is the density of ...
*April 14, 2011*

**Physics**

PROJECTILE LAUNCHED FROM EARTH'S SURFACE? A projectile is shot straight up from the earth's surface at a speed of 1.20×10^4km/hr. How high does it go? (answer in km) Supposed to solve this using F=G(mm/2r)...?
*April 12, 2011*

**Physics**

Speed of Asteroids With the same Radius? Two spherical asteroids have the same radius R . Asteroid 1 has mass M and asteroid 2 has mass 2M. The two asteroids are released from rest with distance 10R between their centers. What is the speed of each asteroid just before they ...
*April 12, 2011*

**Physics**

Finding a Lunar lander's Thrust? A 6000kg lunar lander is in orbit 50km above the surface of the moon. It needs to move out to a 200km -high orbit in order to link up with the mother ship that will take the astronauts home. How much work must the thrusters do in joules?
*April 12, 2011*

**Physics**

An 9.00-cm-diameter, 400 sphere is released from rest at the top of a 1.90-m-long, 20.0 incline. It rolls, without slipping, to the bottom. A) What is the sphere's angular velocity at the bottom of the incline? B) WWhat fraction of its kinetic energy is rotational?
*April 10, 2011*

**physics please help!**

Suppose that 90 g of hot water at a temperature of 75 degrees C is poured into a cavity in a very large block of ice at 0 degrees C. (a) What will be the final temperature of the water in the cavity? (b) What mass of ice must melt in order for the water to cool down to the ...
*April 8, 2011*

**math**

the density of a diamond is 3.52 grams per cubic centimeter. Sally has a diamond that has a volume of 20 mm^3. What is the weight of the diamond?.
*April 6, 2011*

**math**

Thank you!!
*April 6, 2011*

**math**

The density of a crystal is 2.65 grams per cubic centimeter. Ryan has a rectangular prism made of quartz. It measures 10 cm by 10 cm by 6 cm. Find the weight of this crystal in kilograms.
*April 6, 2011*

**math**

i am greater than 15 and less than 40.if you double me, i become a number that ends in 0.1/5 of me is equal to 5.
*April 5, 2011*

**Chemistry**

Thanks a lot man!
*April 3, 2011*

**Chemistry**

The Ksp for a certain metal hydroxide, M(OH)2 (molar mass = 127) is 3.5 × 10-19. What is the pH for a saturated solution of this hydroxide? Confused on how to set up this problem...
*April 3, 2011*

**Maths**

What is 5y=9+2y
*March 30, 2011*

**Physics**

An object initially at a temperature of 80 C cools by 1 C in a time of 15 s when placed in a 20 C room When the object's temperature reaches 50 C, what is the average rate at which the object cools?
*March 28, 2011*

**math**

Consider the polynomial x^3 + 6x^2 + 3x - 10. Without dividing, or graphing, which two of (x+2), (x-2), (x+1), and (x-1) must be factors of the polynomial? Why/how do you know?
*March 27, 2011*

**math**

Find an equation of a polynomial function of degree 5 with integer coefficients with zeros 0, -2, and 1/2.
*March 27, 2011*

**algebra**

Find an equation of a polynomial function of degree 5 with integer coefficients with zeros 0, -2, and 1/2.
*March 27, 2011*

**math**

What percentage of 13,000.00 is 8,000.00
*March 23, 2011*

**Physics**

A 1900 car starts from rest and drives around a flat 50--diameter circular track. The forward force provided by the car's drive wheels is a constant 1300 . A) What is the magnitude of the car's acceleration at ? B) What is the direction of the car's acceleration at...
*March 15, 2011*

**Physics**

A 30.0 ball rolls around a 50.0 -diameter L-shaped track, shown in the figure, at 60.0 . What is the magnitude of the net force that the track exerts on the ball? Rolling friction can be neglected.
*March 15, 2011*

**Physics**

A rocket-powered hockey puck has a thrust of 2.40 and a total mass of 1.40 . It is released from rest on a frictionless table, 2.90 from the edge of a 1.80 drop. The front of the rocket is pointed directly toward the edge. How far from the table does the puck land?
*March 15, 2011*

**chemistry**

What reagent converts sodiumethanoate to methane?
*March 15, 2011*

**math**

The larger circle has a radius that is 18 inches longer than the smaller circle. The larger circle has a circumference that is A pi feet larger then the smaller circle. find the value of a.
*March 15, 2011*

**BIOCHEM**

what are the problems created by using molecular oxygen as a recipient of the electrons from the oxidation of carbon compounds.
*March 14, 2011*

**math**

How do you find the circumference of a circle?
*March 14, 2011*

**Physics**

The puck accelerated 6m/s in 2s, which (assuming constant acceleration) is 3m/s^2 f = m*a f = 0.200kg * 3m/s^2 = 0.6N From Newton's Third Law, there was 0.6N exerted both on the puck by the stick, and 0.6N on the stick by the puck
*March 14, 2011*

**yes**

Using your current work organization (or an organization of interest) as the subject matter, research the elements of business and prepare an APA formatted paper that:
*March 13, 2011*

**science**

Start early - plant germination takes time regardless of the plant. Also you must be sure to replicate each plants environment as much as possible. Same potting soil, same sunlight, same amounts of liquid at the same time. Also you should have a control group. Since you are ...
*March 7, 2011*

**Chemistry**

Calculate the mass of sodium bicarbonate needed to neutralize 3.0 mL of 3.0 M HCl. Show your work.
*March 2, 2011*

**Chemistry**

Calculate the mass of sodium bicarbonate needed to neutralize 3.0 mL of 3.0 M HCl. Show your work.
*March 2, 2011*

**Physics**

conical pendulum is formed by attaching a 0.200 ball to a 1.00 -long. It has a radius of 40.0cm . What is the angular velocity of the ball if the tension in the string is 2.14N?
*March 1, 2011*

**Physics**

conical pendulum is formed by attaching a 0.200 ball to a 1.00 -long. It has a radius of 40.0cm . What is the tension in the string?
*March 1, 2011*

**Physics**

conical pendulum is formed by attaching a 0.200 ball to a 1.00 -long. It has a radius of 40.0cm . What is the tension in the string?
*March 1, 2011*

**Physics**

conical pendulum is formed by attaching a 0.200 ball to a 1.00 -long. It has a radius of 40.0cm . What is the tension in the string?
*March 1, 2011*

**math**

Not enough information. However, if the problem gave Harry's total amount of money, or a percentage based on the 12 dollars spent, it would be solvable. Think about how you would solve it if this information was given.
*February 28, 2011*

**math**

Make an estimation of how many weeks are in a month. Calculate how many total weeks there are in 8 months. Multiply the weekly gas expense by the total number of weeks.
*February 28, 2011*

**8th grade science**

velocity is speed with direction For example.... An airplane is flying East at 300 miles per hour Its speed is 300 miles per hour Its velocity is 300 miles per hour East
*February 28, 2011*

**physics**

Frequency is the number of waves that pass by in one second. You know that 8 waves pass by in 30 seconds. How many pass by in 1 second? Period is the time it takes for one wave to pass by. Period is the inverse of frequency (T = 1/f). Wavelength is the distance measured from ...
*February 28, 2011*

**Physics**

This problem can be solved with the conservation of energy. The total amount of energy in the car is the same before and after the collision with the spring. The car's kinetic energy before the collision is completely converted to spring potential energy after the ...
*February 28, 2011*

**English**

Is "after the hurricane" a pharase or clause?
*February 27, 2011*

**science**

The best thing I have done for conversions throughout all of my education was learn this saying: Kings over Humans over Dragons over Dogs over Cats over Mice (or if you prefer: "King Henry Died Drinking Chocolate Milk) broken down that gives: K H D * D C M this is short ...
*February 27, 2011*

**Math**

u x 6 2/3=20
*February 26, 2011*

**PHYSICS**

The weight of fully saturated soil in a prism having a 4.00 sq. ft. base (or a base of 4.00 ft*ft) is 4,000 lbs. Pore pressure at the base is 499 lbs/(ft*ft). True or False: The effective stress at the base is 501 lbs/(ft*ft).
*February 26, 2011*

**Math-Statistics**

D. Within 239 to 507 minutes.
*February 21, 2011*

**Physics (Force and Motion)**

392 N
*February 19, 2011*

**groundwater science**

Assume that a losing stream exists in physical connection with groundwater in an isotropic unconfined aquifer. Assume that several contour lines of equal head cross the stream and intercept it. These contour lines of equal head are "V-shaped", with the point of the &...
*February 19, 2011*

**Math/Radioactive Dating**

No Calculator Necessary. Age 0: 0 Ar40 Age 1.25 billion years: half of the K40 is now Ar40, so 1 part of K40 and 1 part of Ar40 Age of 2.5 billion years: one quarter K40 and three quarters Ar40; so 1 part K40 to 3 parts of Ar 40
*February 19, 2011*

**Physics-Resonance**

A 3.00 m long pipe is in a room where the temperature is 20 C. What is the fundamental frequency if the pipe is closed at one end? Would this count as an open pipe still, or a closed pipe? This is what I did. Wavelength = 2L/n Wavelength = 2(3)/1 Wavelength = 6 (331 + (.6*20...
*February 14, 2011*

**chemistry**

19. Convert 15 ppm of benzene to mg/m3 at 20 oC and 720 torr Density of a gas is g/L = P(MW)/RT (740 torr x 1 atm/760torr)(78.114g/mole)/ (.0821L atm/mole K)(293K) = 3.16g/L 1ppm =1 L Benzene/106 L of air = 1L ben/1000 m of air = 0.001 L ben/m3 = 0.00316 g/m3 x/3.16=15 = 47....
*February 14, 2011*

**CHEMISTRY**

19. Convert 15 ppm of benzene to mg/m3 at 20 oC and 720 torr Density of a gas is g/L = P(MW)/RT (740 torr x 1 atm/760torr)(78.114g/mole)/ (.0821L atm/mole K)(293K) = 3.16g/L 1ppm =1 L Benzene/106 L of air = 1L ben/1000 m of air = 0.001 L ben/m3 = 0.00316 g/m3 x/3.16=15 = 47....
*February 14, 2011*

**CHEMISTRY**

19. Convert 15 ppm of benzene to mg/m3 at 20 oC and 720 torr Density of a gas is g/L = P(MW)/RT (740 torr x 1 atm/760torr)(78.114g/mole)/ (.0821L atm/mole K)(293K) = 3.16g/L 1ppm =1 L Benzene/106 L of air = 1L ben/1000 m of air = 0.001 L ben/m3 = 0.00316 g/m3 x/3.16=15 = 47....
*February 14, 2011*

**CHEMISTRY**

Benzene equals 78.11 grams/mole
*February 14, 2011*

**CHEMISTRY**

Grams/mole benzene
*February 14, 2011*

**science**

12. Aluminum in blood plasma was shown to undergo a first order elimination reaction with a half-life of 160 days. If the initial concentration was 8.2 µg/L, how long will it take for the concentration to drop to 2.5 µg/L?
*February 13, 2011*

**groundwater science**

For one dimensional flow, what is the flow rate in a 2.0-m long sample of clean saturated sand having a cross-sectional area of 0.05 m2, and a hydraulic conductivity value of 10-3 m/s, if the drop in head over the length of the sand sample is 0.03 m?
*February 11, 2011*

**Physics**

Two waves are combined to form this standing wave equation of y(x,t) = (3 mm)sin[x/(2 m]cos[(100 rad/s)t] a. What's the amplitude of the right moving wave and left moving wave? b. What's the wavelength of the right moving wave and left moving wave? c. What's the ...
*February 11, 2011*

**Physics**

For the second part, since this is a sine function, there's a particular angle that would have the same value as 0.8333. Like sin(0 deg) and sin(180 deg) equals to 0. So I did 180 - 56.4 to get that particular angle. Once I got that, I converted it to radians and repeated ...
*February 6, 2011*

**Physics**

Thanks, I wasn't able to get the second part of the answer (got a spring constant of 24.21 N/m) correct though.
*February 6, 2011*

**Physics**

A particle of mass m = 0.40 kg oscillates on the end of a spring with an amplitude of 0.30 m. At t = 0, it's at it's equilibrium position (x=0) and is moving in the positive x-direction. At 0.20 s later it is at x = 0.25 m. a. What is the lowest possible value for the ...
*February 6, 2011*

**soil science**

True or False: for a particular soil, pressure just under the water table is negative
*February 5, 2011*

**groundwater science**

what is weight density (lbs/ft3)of a fluid filling a cylinder 1.4 ft high and cross section area of 0.2ft2 if the fluid weighs 15.1 lbs?
*February 4, 2011*

**MGT 460 Leadership Priorities & Practice**

does not suggest that Catherine goes to see every romantic comedy that plays at her local movie theater
*February 4, 2011*

**Math**

Moira paid $4.50 for a movie and 2 bags of popcorn. All together she spent 6 dollars. What's the cost for a bag of popcorn?
*February 3, 2011*

**marketing**

What are the three essential lessons from Theodore Levitt's Marketing Myopia?
*January 30, 2011*

**Pre Calc**

√(x+2) -7 =√(x+9)
*January 23, 2011*

**Calculus **

√(x+2) -7 =√(x+9) If you could show your work on how to get the answer that would be awesome. I really need to learn how to do this
*January 23, 2011*

**physics**

A space vehicle is coasting at a constant velocity of 20.5 m/s in the +y direction relative to a space station. The pilot of the vehicle fires a RCS (reaction control system) thruster, which causes it to accelerate at 0.390 m/s2 in the +x direction. After 49.0 s, the pilot ...
*January 21, 2011*

**literature ... i really need corrections**

thank you...
*January 21, 2011*

**english.. can u tell me if my answers are right**

1)c 2)c 3)c 4)c .. k this looks ridiculous but i think the answers are all C !!! please check!!! 1) At the end of the poem(song of myself number 52), the speaker a.proclaims his love to democracy b. encourages us to read more of his poems c. reaffirms his link to the reader d...
*January 21, 2011*

**english**

i've read most of these sites but couldn't really make sure of my answers i mean for example number 1 i was and still is confused between a and d ... i am not really able to comprehend the question. do you think my answers are right? it would really help
*January 20, 2011*