Tuesday

September 1, 2015
Total # Posts: 2,130

**chemistry**

10.5 g sample of copper metal at 25.0°C is heated by the addition of 150.0 J of energy. The final temperature of the copper is _____°C. The specific heat capacity of copper is 0.38 J/ goC.
*June 29, 2015*

**chemistry**

A lactic acid/lactate ion buffer solution contains 0.43M HC3H5O3 and 0.90M C3H5O3-. The value of lactic acid is 1.4*10-4 calculate the pH of this buffer
*June 16, 2015*

**chemistr**

What mass of HNO3 is needed to prepare 400mL of 0.25N solution?
*June 16, 2015*

**chemistry**

How many equivalents of an acid or base are in the following? 0.43mol Mg(OH)2 and 2.8g Mg(OH)2?
*June 16, 2015*

**chemistry**

What volume of 0.076M HNO3 is required to titrate 20.0ML of 0.25M Ba(OH)2 solution? use 2 sig figures
*June 16, 2015*

**chemistry**

If 32.9mL of 0.170M BaCl2 are needed to react completely with 35.0mL of 0.160M Na2SO4 . How many grams of BaSO4 will be formed?
*June 15, 2015*

**chemistry**

how many grams of methanol must be added to 5.00kg of water to lower its freezing point to -12.0 degrees C? for each mole of solute the freezing point of 1kg of water is lowered 1.86 degrees C?
*June 14, 2015*

**chemistry**

what is the freezing point of a solution that contains 20.2g of urea CO(NH2)2 in 295mL water? Assume a density of water of 1.00g/mL
*June 14, 2015*

**trigonometry**

Thank you Is the answer complete?
*June 13, 2015*

**trigonometry**

Prove that 2sin150*cos315*cos(90-x)/sin(360-x)cos(-240)sin135=2
*June 13, 2015*

**chemistry**

Chemical reaction between solid ammonium chloride and solid barium hydroxide octahydrate 2NH4Cl(s)+Ba(OH)*8H2O(s)->2NH3(aq)+BaCl2(aq)+10H2O(l) the change in heat for this reaction is 54.8kJ how much energy would be absorbed if 24.9g of NH4Cl reacts
*June 7, 2015*

**chemistry**

for N2O4(g)-><-2NO2(g) the value of K at 25 degrees C is 7.19*10-3. calculate N2O4 at equilibrium when NO2 =2.80*10-2 mol/L. Calculate NO2 at equilibrium when N2O4=7.00*10-2 mol/L
*June 7, 2015*

**chemistry**

4HCl(g)+O2(g)-><-2Cl2(g)+2H2O(g) with Hcl=0.80M, Cl2=3.0M, O2=0.20M H2O=3.0M what is the equilibrium constant
*June 7, 2015*

**chemistry**

I2(g)+Cl2(g)-><-2ICl(g) molar concentrations are I2=1.5M, Cl2=0.60M and ICl=5.0M calculate the ratio of products to reactants assume that the reaction has not yet regained equilibrium
*June 7, 2015*

**chemistry**

Fe3O4 can be reduced by treatment with hydrogen to yield iron metal and water vapor write the balanced equation. this process required 36kcal for every 1.00 mol of Fe3O4 reduced. how much energy in kcal is required to produce 64g of iron. how many grams of hydrogen are needed ...
*June 7, 2015*

**chemistry**

methanol CH3OH is used as race car fuel write the balanced equation for the combustion of methanol. change in heat= -174kcal/mol methanol for the process How man kilocal are released u burning 33.0g of methanol
*June 7, 2015*

**chemistry**

That is how my question is worded. How much heat (in kilocalories) is evolved or absorbed in the reaction of 1.94g of Na with H2O? change in heat= -88.0 kcal/mol
*June 7, 2015*

**chemistry**

How much heat in kilocalories is absorbed in the reaction of 1.94g of Na with H2O? 2Na(s)+2H2O(l)->2NaOH(aq)+H2(g) change in heat= -88.0kcal/mol
*June 7, 2015*

**chemistry**

During the combustion of 5.00g of octane C8H18, 239.5 kcal is released. Write a balanced equation for the combustion reaction. Are reactants or products favored? What is the sign of change of heat for this reaction? how much energy is released by the combustion of 1.53mol of ...
*June 7, 2015*

**History**

Who wrote the constitution?
*June 5, 2015*

**Dennis **

How many ways can the letters of the word HAPPINESS be arranged. If H must start the word, N must end the word and the P's must be separated? [question from the topic FACTORIAL,PERMUTATION AND COMBINATION ]
*May 29, 2015*

**chemistry**

Thank you
*May 28, 2015*

**chemistry**

24,8% of potassium ,34,77% of Mn,40,5% of oxygen how do i find the emperical formular thanks in advance
*May 28, 2015*

**Physics**

a ray of light is incident on an air-glass boundary at 30 degrees. The index of refraction of air is 1,and the index of refraction for the glass is 1.4. What is the angle of the reflected ray, and what is the angle of the refracted ray? Thanks in advance. Been stuck for three ...
*May 18, 2015*

**Algebra**

A rectangle has a width which is 2/3 of its length. Find its length if its perimeter is 80 cm. Find its dimensions. P = 2L + 2W 80cm = 2L + 2 (2/3)L 80cm =6/3 L + 4/3L 80cm = 10/3 L 80. 3/10 = L 24cm =L or L= 24 cm W = 2/3 .24 W = 16 cm
*May 16, 2015*

**Social Studies**

What did Isaac Singer do to improve American society? and what did he do that may not have been so good? Isaac Singer invented a way to make improvements to the sewing machine in an effort to boost up the sewingn industry and to create a better reliable way of sewing clothes. ...
*April 27, 2015*

**The villages**

(x+3)/(x^2-2x-8)- (x-5)/(x^2-12x+32)
*April 27, 2015*

**Physics**

A 20 C charge experiences a 2 N force in an electric field. What is the strength of the electric field?
*April 27, 2015*

**Technical Physics**

Consider a hypothetical situation, where your friend suggests leaving the refrigerator door open to help cool the house on a hot summer day. Discuss what will happen to the temperature of the room. Will it decrease, increase, or stay the same and why?
*April 24, 2015*

**Physics**

A 3.40 kg block of copper at a temperature of 74 °C is dropped into a bucket containing a mixture of ice and water whose total mass is 1.20 kg. When thermal equilibrium is reached the temperature of the water is 14 °C. How much ice was in the bucket before the copper ...
*April 23, 2015*

**Physics**

You will use the formula p*V = kB*N*T to find the depth of the box (front to back measurement). The volume of the box is given by the formula V = W * H * D. (You will need to convert the pressure from atm to Pa, or pascals, by multiplying atms by 1 * 105.) The height of the ...
*April 19, 2015*

**phyiscs**

Water flows through a 4 cm diameter garden hose at a velocity of 2 m/s. What is the velocity of the water if a nozzle is used with a diameter of 0.5 cm? please help..thanks in advanced
*April 16, 2015*

**Physics 2**

Calculate the maximum height using the initial speed, half-time, and angle. The initial speeed is 9.8m/s, half time is 1.8, and the angle is 75.
*April 13, 2015*

**Physics**

Calculate the maximum height using the initial speed, half-time, and angle. The initial speeed is 18m/s, half time is 1.8, and the angle is 75
*April 13, 2015*

**Science**

A Herculean bomber jet accepts 40kg of air per second at a velocity of 200m/s, burns 2kg of fuel at the same time,and releases exhaust gases at 600m/s relative to the bomber. find the thrust due to its engine.
*April 12, 2015*

**music**

seems to justify a departure from traditional presentations of music and culture of the Caribbean?
*April 11, 2015*

**math**

Water is falling on a surface, wetting a circular area that is expanding at a rate of 9 mm2 /s. How fast is the radius of the wetted area expanding when the radius is 120 mm? (Round your answer to two decimal places.)
*April 10, 2015*

**math**

A rectangular field is to be enclosed on four sides with a fence. Fencing costs $8 per foot for two opposite sides, and $2 per foot for the other sides. Find the dimensions of the field of area 900 ft2 that would be the cheapest to enclose.
*April 10, 2015*

**music**

What is denoted by "Caribbean music in a new mode."
*April 10, 2015*

**math help**

how do prove that this equation has rational roots for all rational values of K 3x^2+kx-k=3x
*March 31, 2015*

**IT**

Build a PowerPoint ® presentation that will address each of the Project Management Areas of Knowledge, the process groups that use these areas of knowledge, and how the process groups interact with the knowledge area processes. Use table 3-1, Project Management Process ...
*March 30, 2015*

**literature**

I hear the locomotives rushing and roaring, and the shrill steamwhistle. What do the s and sh sounds suggest? What do the r sounds suggest?
*March 30, 2015*

**literature**

why is the poem "Fable for when there's no way out" a good example of "seeing common things in an uncommon way?"
*March 30, 2015*

**literature**

what lines show alliterations in the poem "Fable for when there's no way out"
*March 30, 2015*

**Please help me with Psychology**

What type of study would be appropriate for this situation: Determine whether regular meditation will help depression.
*March 24, 2015*

**Physics**

A 4.5-kg brick is suspended by a light string from a 2.0-kg pulley. The brick is released from rest and falls to the floor below. The pulley may be considered a solid disk of radius 1.5 m. What is the linear acceleration of the brick and the tension in the string?
*March 23, 2015*

**Physics**

A 180-kg uniform horizontal beam is attached to a vertical wall at one end and is supported by a vertical cable at the other end making an angle of 30 degree above the x axis. What is the magnitude of the tension in the cable?
*March 23, 2015*

**Physics**

A uniform plank of length 4.1 m and weight 240 N rests horizontally on two supports, with 1.1 m of the plank hanging over the right support. To what distance x can a person who weighs 445 N walk on the overhanging part of the plank before it just begins to tip?
*March 23, 2015*

**trig**

If cos A= -6/7, in quadrant 2, determine the exact value of tan 2A I don't understand how to do this?
*March 22, 2015*

**Advanced functions**

If cos A= -6/7, in quadrant 2, determine the exact value of tan 2A I don't understand how to do this?
*March 22, 2015*

**math**

My car gets 26 miles per gallon, I have to drive 36 miles, gas price is $3.10 per gallon. How much money will I need?
*March 20, 2015*

**Life orientation**

List two ways in which sport can support nation building
*March 20, 2015*

**Algebra**

Please check my answer and let me know if it is right or not. 25+.32m(800)=281 28+.30(400)=148 70+40+2(30+.29)=830 +.29m
*March 15, 2015*

**physics**

The drive propeller of a ship starts from rest and accelerates at 2.90×10-3 rad/s2 for 2.10×103 s. For the next 1.40×103 s the propeller rotates at a constant angular speed. Then it decelerates at 2.30×10-3 rad/s2 until it slows (without reversing ...
*March 9, 2015*

**physics**

The sun has a mass of 1.99 × 1030 kg and is moving in a circular orbit about the center of our galaxy, the Milky Way. The radius of the orbit is 2.3 × 104 light-years (1 light-year = 9.5 × 1015 m), and the angular speed of the sun is 1.1 × 10-15 rad/s. ...
*March 9, 2015*

**physics**

A motorcycle, which has an initial linear speed of 6.6 m/s, decelerates to a speed of 2.1 m/s in 5.0 s. Each wheel has a radius of 0.65 m and is rotating in a counterclockwise (positive) direction. What are a) the constant angular acceleration (in rad/s^2) and b) the angular ...
*March 9, 2015*

**Physics**

An explosion breaks an object initially at rest into two pieces, one of which has 2.0 times the mass of the other. If 7300 J of kinetic energy were released in the explosion, how much kinetic energy did the lighter piece acquire?
*March 5, 2015*

**Physics**

A cue ball traveling at 0.70 m/s hits a stationary 8-ball, which moves off with a speed of 0.23 m/s at an angle of 39° relative to the cue ball's initial direction. Assuming that the balls have equal masses and the collision is inelastic, at what angle will the cue ...
*March 5, 2015*

**Physics **

Object A is moving due east, while object B is moving due north. They collide and stick together in a completely inelastic collision. Momentum is conserved. Object A has a mass of mA = 17.0 kg and an initial velocity of VoA = 8.15 m/s, due east. Object B, however, has a mass ...
*March 5, 2015*

**Physics**

During a workout, the football players at Rutgers State University ran up the stadium stairs at a steady pace in 48 s. The stairs are 135 m long and inclined at an angle of 35 degree. If a typical player has a mass of 120 kg, estimate the average power output on the way up. ...
*March 5, 2015*

**Physics**

A car of mass 1490 kg traveling at 22 m/s is at the foot of a hill that rises 115 m in 3.2 km. At the top of the hill, the speed of the car is 12 m/s. Find the average power delivered by the car's engine, neglecting any frictional losses.
*March 5, 2015*

**Impulse and Momentum**

A bullet of mass m is fired at speed v0 into a wooden block of mass M. The bullet instantaneously comes to rest in the block. The block with the embedded bullet slides along a horizontal surface with a coefficient of kinetic friction . What is the algebraic expression ...
*March 1, 2015*

**Impulse and Momentum**

In the game of billiards, all the balls have approximately the same mass, about 0.20 kg. The cue ball moving west with a speed of 4.5m/s strikes another ball at rest. After the collision the cue ball moves at an angle of 55degree north of west and the other ball at an angle of...
*March 1, 2015*

**Impulse and Momentum**

A 1400-kg car traveling east at 25m/s collides with a 1800-kg car traveling at a speed of 20m/s in a direction that makes angle of 40degree south of west. The cars stick together after the collision. What is the magnitude and direction of the velocity of the cars after the ...
*March 1, 2015*

**accounting**

Describe how the separation of (1) authorization of production transactions, (2) recording of these transactions, and (3) physical custody of inventories can be specified among the production, inventory, and cost accounting departments. How does the production order document ...
*February 27, 2015*

**Algebra II**

what is an equation of a parabola with the given vertex and focus? Vertex: (-2,5); focus: (-2,6)
*February 26, 2015*

**math**

Given the equation y equals one third x + 7 what would it be easy y value for the corresponding x value of 18
*February 26, 2015*

**Physics**

How to determine the work done on the object with a FCosTheta(Y axis)-Displacement(X axis) graph.
*February 23, 2015*

**Physics**

At an accident scene on a level road, investigators measure a car's skid mark to be 68 m long. It was a rainy day and the coefficient of friction was estimated to be 0.40. Using the work-energy theorem determine the speed of the car when the driver slammed on (and locked) ...
*February 22, 2015*

**Physics**

A rescue helicopter lifts a 70 kg person straight up by means of a cable. The person has an upward acceleration of 0.70 m/s2 and is lifted from rest through a distance of 9 m. What is the tension in the cable? How much work is done by the tension in the cable...
*February 22, 2015*

**algebra**

sarah is twice as old as katie. 10 years ago, the sum of their ages was 23. How old are they now
*January 14, 2015*

**science**

What is Eugenics and what were the goals and policies of the American Eugenics movement?
*January 13, 2015*

**Math- algebra**

If a ball is thrown directly upward with a velocity of 26 ft/s, its height (in feet) after t seconds is given by y = 26t − 16t^2. What is the maximum height attained by the ball? -Please just post answer if possible, my calculations are off. Just want to make sure I am ...
*December 17, 2014*

**Science **

Why are there variations in atmospheric pressure how was this proven? Why do your ear pop when trebling to different altitudes?
*December 15, 2014*

**Math**

When Curtis was born, his parents began depositing $1000 at the end of every year into an annuity to save for his college education. If the account paid 7% compounded annually for the first 10 years and then dropped to 5% for the next eight years, how much is the account worth...
*December 11, 2014*

**Math**

Thank you by the way! I appreciate it.
*December 11, 2014*

**Math**

Yes, that was right. I must have put in the wrong numbers at first when I was doing it so I thought I was using the wrong formula.
*December 11, 2014*

**Math**

Young and Company owes bond holders $5,500 interest at the end of each quarter for the next five years. How much must they deposit now at 8% interest compounded quarterly to yield an annuity payment of $5,500? -- I am pretty sure I know how to do the problem but I am just ...
*December 11, 2014*

**Chemistry**

You read a reversible reaction from left to right in the forward direction. This direction shows which of these occurring? a) the reactants forming a product b) the product decomposing to form reactants c) both a and b occurring d) b occurring, followed by a e) none of the ...
*December 8, 2014*

**Help with Statistics (T-value and decision rule)**

For a random sample of 12 observations, the sample mean was 407 and the standard deviation was 6. Using the .05 significant level, answer the following questions. What would the t value be? What is the decision rule? **** I think the t-value would be t = -3.0845 Any help would...
*December 5, 2014*

**Math please check**

I know the answer to the first one is "e" and the answer to the second one is "a "but I have no idea why please explain how to do these two problems. I am very confused with this new method. Thank you! The “Cobb-Douglas” productivity function for ...
*December 5, 2014*

**Physics**

The brakes of a bike (with a person) having a mass of 63 kg, reduces it's velocity from 8.5 m/s to 0 m/s in 3.0 seconds. What is the magnitude of braking force?
*December 5, 2014*

**Physics**

super mouse steals a large piece of cheese by rolling it across the floor with a force of 5.0 N. If the cheese has a mass of 50 kg with what acceleration does the cheese move? If super mouse's force remains constant, what will be the speed of the rolling cheese
*December 5, 2014*

**Calculus question please explain**

I know the answer to the first one is "e" and the answer to the second one is "a "but I have no idea why please explain how to do these two problems. I am very confused with this method. Thank you! The “Cobb-Douglas” productivity function for a ...
*December 5, 2014*

**Physics**

A 31.5 N object is in free fall. What is the magnitude of the net force which acts on the object? Answer in units of N
*December 4, 2014*

**Chemistry**

so if I multiply the mL to the solution how does that give me the moles of propanioc acid? and what about the glycerol?
*December 3, 2014*

**Chemistry**

If 325mL of a 0.58 M solution of a propanoic acid (a fatty acid) was mixed with excess glycerol what is, the maximum number of molecules of fat or oil that could result?(you will need Avogadros number = 6.022 X 10 to the 23rd power)....I need to show all work and im completely...
*December 3, 2014*

**Physics**

A 4.26 kg block starts up a 33.0 degree incline at 7.81 m/s. How far will it slide if the coefficient of kinetic friction is 0.23?
*November 30, 2014*

**What is the best estimate of the population mean?**

The Jolliebee hamburger chain specializes in half-pound hamburgers. The sales follow a normal distribution. The standard deviation of the distribution for daily sakes is $3000. A sample of 40 showed the mean daily sale to be $20,000. What is the best estimate of the population...
*November 30, 2014*

**science**

how many moles of oxygen gas are necessary to form 0.737 moles of carbon dioxide
*November 24, 2014*

**Calculus Please check**

Please check my answers and let me know if I did something wrong. Thank you! Find the partial derivative of x, and the partial derivative of y, then the partial derivative of x (1,-1), and the partal derivative of y (1,-1). f(x,y) = x^4 y^2 -x here is what I got @f/@x = 3x^3 y...
*November 20, 2014*

**Please help me with statistics**

I was asked to: Calculate the d value or effect size for A but use this data instead. A. Group one 12 and group two 11 standard deviation 3 Can anyone please help me figure out how to find the d value. Any help would be great.
*November 20, 2014*

**Honors Science**

Why would vinegar be expressed in liters and milliliters?
*November 16, 2014*

**Calculus Please Help**

I think I have the right answer, but I am not 100% sure how to do the values at (1,-1) and the one below at (0,-1, 1). Please explain how I need to approach how to do these. Thank You! Calculate the partial derivative @f/@x, @f/@y and @f/@x | (1,-1), and @f/@y | (1,-1) f(x,y...
*November 13, 2014*

**Math please check**

I think I have the right answer, but I am not 100% sure how to do the values at (1,-1) and the one below at (0,-1, 1). Please explain how I need to approach how to do these. Thank You! Calculate the partial derivative @f/@x, @f/@y and @f/@x | (1,-1), and @f/@y | (1,-1) f(x,y...
*November 13, 2014*

**calculus**

A large container has the shape of a frustum of a cone with top radius 5 m, bottom radius 3m, and height 12m. The container is being filled with water at the constant rate 4.9 m^3/min. At what rate is the level of water rising at the instant the water is 2 deep? the finial ...
*November 8, 2014*

**Calculus**

Sorry Mr Steve I submitted your answer and It was wrong answer the right answer = 14.0 cm/min Could You please tell me how to do this question because I have to do it again with different values.
*November 7, 2014*

**Calculus**

A large container has the shape of a frustum of a cone with top radius 5 m, bottom radius 3m, and height 12m. The container is being filled with water at the constant rate 4.9 m^3/min. At what rate is the level of water rising at the instant the water is 2 deep?
*November 7, 2014*