Friday

February 27, 2015

February 27, 2015

Total # Posts: 626

**Chemistry**

What is the name of the substance with formula Cu(H2O)6SO4?
*February 17, 2015*

**Chemistry, HELP!!**

Write two hydrolysis reactions for Cu^2+ reacting with water in each step to form CuOH^+ and Cu(OH)2. The hydrolysis constants for the two reactions are: log kh1 = -7.7 and log Kh2 = -6.1
*February 8, 2015*

**physics**

An object falls a distance h from rest. If it travels 0.45h in the last 1.00 s, find the time and the height of its fall.
*February 6, 2015*

**physics**

A stone is dropped into a river from a bridge 43.8 m above the water. Another stone is thrown vertically down 1.65 s after the first is dropped. Both stones strike the water at the same time. What is the initial speed of the second stone?
*February 6, 2015*

**physics**

The figure gives the acceleration a versus time t for a particle moving along an x axis. The a-axis scale is set by as = 15.0 m/s^2. At t = -2.0 s, the particle's velocity is 7.00 m/s. What is its velocity at t = 6.0 s?
*February 6, 2015*

**Chemistry Please help !**

the unit is in amu unit
*February 4, 2015*

**Chemistry Please help !**

Carbon tetrachloride contains one carbon and four chlorine atoms. For this compound 11.818 g of chlorine combine with 1.000 g of C-12. Using this information, calculate the atomic mass of chlorine.
*February 4, 2015*

**Physics **

7. An early objection to the idea that the earth is spinning on its axis was that the earth would turn so fast at the equator that people would be thrown into space. Show the error in this logic by calculating the centripetal force needed to hold a 100. kg person in place at ...
*February 2, 2015*

**math**

Given only an 11 liter jug and an 8 liter jug, each with no markings, find the method of using the two jugs to measure out eactly 1 liter of water while using the smallest amount of water. Argue clearly why you think that your procedure uses the smallest amount!
*January 9, 2015*

**geometry**

how do you find the speed of the plane 130 miles per hour, cross wind 20 miles hour
*December 27, 2014*

**marh**

Daryl reaned 426 points out of 500 points in English class. Which represent approximately represents Darl's points?
*December 16, 2014*

**Calc I**

Find an equation of the tangent to the curve at the given point. y=4(sinx)^2 point: pi/6,1) So I took the derivative of the original function to get: y' = 8cosx*sinx I then chose a point to plug in to find a point for the slope. i picked pi/6 because i thought it would be ...
*December 7, 2014*

**Calc I**

if f(t)=sqrt(4t+1) find f''(2) I got the first derivative to be: 1/2(4t-1)^-1/2 * 4t^3 and i'm trying to figure out if i need the product rule again to find the second derivative -1t^3(4t-1)^-3/2 * 4t^3 The answer if -4/27 and I'm not sure how to get that if I...
*December 7, 2014*

**Calc I**

Find the derivative of y=(x^2 + x^3)^4 What I got: 4(x^2+x^3)^3 * (2x+3x^2) The correct answer: 4x^7(x+1)(3x+2) How did they get that?
*December 7, 2014*

**Chemistry (Electrochemistry)**

The standard potential for the following galvanic cell is 1.72V : Be(s)|Be2+(aq)||Pb2+(aq)|Pb(s) The standard reduction potential for the Pb2+/Pb half-cell: E = -.13V Calculate the standard reduction potential for the Be2+/Be half-cell. What I know: Be is the anode Pb is the ...
*December 5, 2014*

**college algebra**

I'm going to assume that the only thing under the square root symbol is the 2. Write your equation with a "y" on the left side: y = √2x+9 And then to find the inverse, you first just switch the x's and the y's, and get, x = √2y+9 And then you ...
*December 1, 2014*

**statistics**

A simple random sample of students is selected, and the students are asked how much time they spent preparing for a test. The times (in hours) are as follows: 1.3 7.2 4.2 12.5 6.6 2.5 5.5 Based on these results, a confidence interval for the population mean is found to be &...
*November 30, 2014*

**CALC 1**

Suppose that h is a function with h'(x) = xe^x. Find all intervals where the function h is concave up. Now, I understand that concavity is determined by the second derivative, so what my question here is, is it just taking the first derivative and then taking it again? Is ...
*November 30, 2014*

**Calculus I**

Hmm, even so though, it doesn't make too much sense. V=x^2h = 100 h= 100/x^2 C = x^2 + 4xh C= 10x^2+4(1)xh C= 10x^2+4x(100/x^2) 10x^2+400x/4x^2 C= 10x^2 + 100/x C'(x) = 20x-100/x^2 20x^3=100 x^3 = 5 5^(1/3) = 1.7099 y = 100/5^(1/3) y = 58.5 That seems like a lot for a ...
*November 28, 2014*

**Calculus I**

An open box with square base is to be constructed. The material for the base costs $10 per square foot. The material for the sides costs $1 per square foot. the box must have an area of 100 square feet. Find the dimensions of the box that minimize cost. What I have so far: A...
*November 28, 2014*

**Math**

A ball rebounds the ground to a height of 72 cm, and each time it rebounds to two thirds of the height. Estimate the total distance the ball travels before it comes to rest
*November 22, 2014*

**physics**

In the figure, a 4.3 kg block is accelerated from rest by a compressed spring of spring constant 660 N/m. The block leaves the spring at the spring's relaxed length and then travels over a horizontal floor with a coefficient of kinetic friction μk = 0.260. The ...
*November 15, 2014*

**riga technical university**

At what concentration of silver electrolyte the potential of the silver elevtrode will be greater than 0.1V of the silver electrode standard potential?
*November 4, 2014*

**programming**

create the logic for a program that calculates and displays the amount of money you would have if you invested $5000 at 2 percent simple interest for one year. create a separate method to do the calculation and return the result to be displayed.
*October 28, 2014*

**Math**

Tina is trying to choose finger food for her party. She is choosing between 5 types of nuts, 5 types of crackers, and 4 types of cheese. If Tina chooses one of each,how many combinations does she have to choose from?
*October 18, 2014*

**physics**

A railroad flatcar is loaded with crates having a coefficient of static friction of 0.394 with the floor. If the train is moving at 57.1 km/h, in how short a distance can the train be stopped at constant acceleration without causing the crates to slide?
*October 16, 2014*

**English**

Which pronoun fits. Another boy and him/he won blue ribbons for their work.
*October 14, 2014*

**physics**

An 80 kg skateboarder going 10 m / s is launched nearly vertically off a ramp as shown. Approximately how high does he go?
*October 11, 2014*

**english**

what three jobs besides author did david keys have.
*October 10, 2014*

**Chemistry**

v is1/2 mv squared 2
*October 10, 2014*

**Chemistry, HELP!!**

a) If the volume of a flask is 165 mL and the mass of the vapor in the flask is 0.2136 grams, what is the density of vapor in the flask? b)If the temperature of the vapor is 25 degrees Celsius, what is the molecular weight of the vapor? (Assume the gas pressure to be 1.00 atm.)
*September 23, 2014*

**Chemistry, empirical formula**

Determine the empirical formula for the following compounds with these compositions (by mass): a) Cr 47.7% F 52.3% b) Na 42.1% P 18.9% O 39.0%
*September 23, 2014*

**Math**

I understand that part, but what about the subintervals
*September 11, 2014*

**Math**

consider the polynomial (x-a)(x-b)and the real number line Identify the points on the line where the polynomial is zero. In each of the three subintervals of the line, write the sign of each factor and the sign of the product.For which values does the polynomial possibly ...
*September 11, 2014*

**physics**

a large aircraft accelerates sown the runway for a distance of 3000m before leaving the ground. It then climbs at a steady 3 degree angle. After the plan has travelled 4000m along this new trajectory, how high is it and how far horizontally is it from its initial position?
*September 9, 2014*

**Math**

297x^2 - 167x - 100 Can someone help me find the roots of this
*September 8, 2014*

**statistics**

Use the given sorted values below which are the numbers of points scored in the Super Bowl for a recent period of 24 years. 36 37 37 39 39 41 43 44 44 47 50 53 54 55 56 56 57 59 61 61 65 69 69 75
*August 10, 2014*

**Math**

One model of Earth's population growth is , where t is measured in years since 1990, and P is measured in billions of people. Which of the following statements are true?
*August 6, 2014*

**math**

121
*July 17, 2014*

**Algebra**

Thank you for helping Ms. Sue.
*June 12, 2014*

**Algebra**

A rectangular Persian carpet has a perimeter of 212 inches. The length of the carpet is 24 inches more than the width. What are the dimensions of the carpet?
*June 12, 2014*

**Math**

At a carnival, Linda bought packs of tickets each. She has used of the tickets so far. How many tickets does she have left?
*June 9, 2014*

**math Question**

Find an equation that models a hyperbolic lens with a=12 inches and foci that are 30 inches apart. assume that the center of the hyperbola is the origin and the transverse axis is vertical.
*May 19, 2014*

** algebra**

The first angle of a triangle is 23° more than the 2nd angle. The 3rd angle of a triangle is 6 times the 2nd angle. Use X to represent the unknown value
*May 11, 2014*

**Math**

6 because you have to change mixed numbers into improper fractions do 1 1/2 becomes 3/2 and 4x(3/2) = 6.
*April 29, 2014*

**Chemistry**

The part of an electrochemical cell that carries electrons to a reacting ion is a(n) (1) cathode (2) anode (3) electrode (4) electrolyte
*April 22, 2014*

**Global History**

Vietnam was not originally what France primarily wanted. Explain the value of Vietnam at the time. The time period is around the Vietnam war!
*March 23, 2014*

**MATH**

A photograph has been enlarged to three times its previous size. By what percentage has the size of the photograph increased?
*March 8, 2014*

**Chemistry**

Compare the physical and chemical properties of acids and bases.
*March 4, 2014*

**Chemistry**

Element P electron configuration is 2-8-8-1 Element Q electron configuration is 2-8-18-7
*February 25, 2014*

**Health**

Explain how homelessness is a health-related social issue.
*February 24, 2014*

**Chemistry**

Explain how a person bailing out a row boat with a leak could represent a state of physical equilibrium.
*February 12, 2014*

**math**

Input output table like this 0 in no output 2/3 in 17/6 out 11/4 in ? Out 3 in 13/3 out - in 13/2 out ?
*January 14, 2014*

**Science**

Thanks you very very much !
*January 6, 2014*

**Science**

How are are the viruses, bacteria, fungi, and protists similar? are the all living things or only visisble to through a microscope or infectious diseases??
*January 6, 2014*

**social studies**

Which of the following statements about the natural resources of the United States is most accurate? A. The many agricultural resources of the United States have made up for its lack of other resources. B. U.S. industry and agriculture have prospered because America has many ...
*December 23, 2013*

**LANGUAGE ARTS**

what is number 2 and 3
*December 18, 2013*

**5th Grade Math**

Complete the knput output table write the rule. 0 in - out 3/2 in 17/6 out 11/4 in - out 3 in 13/3 out - in 13/2 out i don t understand
*November 26, 2013*

**Physics**

A baton twirler tosses a baton into the air with an initial angular velocity of 2 rev/s (revolutions per second). The baton undergoes a constant angular acceleration of -.015 rev/s^2 while in the air, and its angular velocity when she catches it is .8 rev/s. Determine the ...
*November 7, 2013*

**Calculus II**

Wow this problem is easier than I thought it was. Thanks.
*November 3, 2013*

**Calculus II**

A cable that weighs 1.5 lb/ft is used to lift 700 lb of coal up a mineshaft that is 400 ft deep. Find the work done.
*November 3, 2013*

**Thomas Nelson **

What is chromatin?
*October 31, 2013*

**Chemistry Hess's Law **

(1) 2 Ni(s) + O2 (g) --> 2NiO(s) delta H= -479.4 kJ (2) Ni(s) + Cl2(g) --> NiCl2(s) delta H= -305.3 kJ Using equations 1 and 2 and Hess's Law, determine the amount of moles Nickel (ii) Chloride that was combusted given the following: volume = 15.45 L pressure = 2.29 ...
*October 23, 2013*

**math**

Verify the given linear approximation at a = 0. Then determine the values of x for which the linear approximation is accurate to within 0.1. (Enter your answer using interval notation. Round your answers to three decimal places.)
*October 20, 2013*

**Math**

Solve for a and b. 2a-ai-5b=0, a-2b-bi=0. Where i is complex number.
*September 28, 2013*

**Math**

Solve x^2+1=0.
*September 28, 2013*

**Math**

Solve x^2+1=0.
*September 28, 2013*

**social studies**

According to the majoritarian model of democracy, what role should public opinion play?
*September 25, 2013*

**physics**

A bullet was fired horizontally from the top of a 1.5x10^2 m tall tower at 2.8x10^2 m/s. Determine its speed on impact with the ground below.
*September 23, 2013*

**math**

Use the formula t = (0.25) s1/2 to find the time t in seconds it will take a stone to drop a distance s of 200 feet. Round your answer to the nearest tenth of a second.
*August 20, 2013*

**ap chemistry**

How would you find the remaining mass of the excess reagent?
*August 1, 2013*

**physics**

A rocket is used to place a satellite in orbit about a planet. The velocity of the satellite is 534 m/s and the radius of orbit is 1.21×108 m. What is the mass of planet?
*July 29, 2013*

**macroeconomics**

b. Now suppose that the gross national debt initially is equal to $2.5 trillion and the federal government then runs a deficit of $100 billion: i. What is the new level of gross national debt? ii. If 100 percent of the deficit is financed by the sale of securities to the ...
*July 28, 2013*

**Finite math**

The manager of a money market fund has invested $4.2 million in certificates of deposit that pay interest at the rate of 5.4%/year compounded quarterly over a period of 5 years. How much will the investment be worth at the end of 5 years?
*July 28, 2013*

**fnite math**

Juan invested $24,000 in a mutual fund 5 years ago. Today his investment is worth $34,616. Find the effective annual rate of return on his investment over the 5-year period.
*July 28, 2013*

**physics**

I solved and got 0.399m and that was wrong, so I don't know...
*July 20, 2013*

**physics **

I'm really confused on this problem too. Does anyone understand how to do it?????????
*July 20, 2013*

**Accounting**

85,000
*July 14, 2013*

**social question**

how much gas do you use to travel 172 miles at 4.00 a gallon.
*July 2, 2013*

**social question**

how much gas do you use to travel 172 miles at 4.00 a gallon.
*July 2, 2013*

**Physics**

Two charges +q and −q are separated by a distance d=50 cm. The electric field lines for this system form the the well-known pattern showed in the figure below. Consider two lines L1 and L2 lying on the same plane and leaving the positive charge at α=±45∘...
*July 1, 2013*

**Math**

Six people are playing Secret Santa for Christmas. They will each give one gift to someone, and each receive one gift from someone. They are not allowed to receive their own gift. How many different ways are there to exchange gifts?
*July 1, 2013*

**Math**

Find an equation for the line that contains the points (2, -3) and (6, 9).
*June 2, 2013*

**Calculus**

ç1 0 x^2dx=1/3. Use this and the properties of integrals to evaluate ç1 0 10−2x^2dx
*May 12, 2013*

**Calculus**

A piece of wire 40 m long is cut into two pieces. One piece is bent into a square and the other is bent into an equilateral triangle. How should the wire be cut so that the total area enclosed is a maximum= minimum= Find the length of the wire used
*May 7, 2013*

**Chemistry**

For a solution of 3.3 M H2CO3 (Ka = 4.4 × 10-7), calculate: (a) [H+] ____?______M (b) pH _____??______ (c) percent ionization ______?______%
*April 30, 2013*

**Math**

What is 1 5 of 20
*April 25, 2013*

**Urgent math**

If f(x, y, z)=sin(3x-yz), where x=e^(t-1), y=t^3, z=t-2, what's df/dt(1)? x(1)=1 y(1)=1 z(1)=-1 df/dt=(3cos(3x-yz))(e^(t-1))+(cos(3x-z))(3t^2)+(cos(3x-y))(1) I seriously need help on this and tell me the answer and show your work through steps. Thanks.
*April 20, 2013*

**Algebra**

A chain store manager hs been told by the main office that daily profit, P, as related to the number of clerks working that day, x, according to the functions P=-25x^2 + 300x. What number of clerks will maximize teh profit, and what is the maximum possible profit?
*April 18, 2013*

**Calculus**

Estimate ç 6 0 6−x^2 dx using 3 right rectangles
*April 18, 2013*

**Calculus**

Estimate ç 6 0 6−x^2 dx using 3 left rectangles.
*April 18, 2013*

**physics**

An aluminum wing on a passenger jet is 38 mlong when its temperature is 23°C.At what temperature would the wing be 2 cm (0.02 m) shorter?
*March 18, 2013*

**Chemistry**

A compound containing only carbon, hydrogen and oxygen is subjected to elemental analysis. Upon complete combustion, a .1804g sample of the compound produced .3051g of CO2 and .1249g of H2O. What is the empirical formula of the compound?
*March 14, 2013*

**Chemistry**

What is the wavelength of an electron traveling at 7.59% of the speed of light?
*March 14, 2013*

**Chemistry**

How many valance electrons are there in [(C2H5)4N]+ ?
*March 14, 2013*

**Chemistry**

What is the C-C-H bond angle in the molecule H2CCO?
*March 14, 2013*

**Chemistry**

What type of reaction will occur when an aqueous solution of lithium chloride is mixed with an aqueous solution of ammonium sulfate?
*March 14, 2013*

**Analytical Chemistry**

Serum taken from a patient being treated with lithium for manic-depressive illness was analyzed for lithium concentration. A reading of 291 units was obtained for the intensity of the 671 nm red emission line. Then 1.00 mL of a 11.7 mM Lithium standard was added to 9.00 mL of ...
*March 5, 2013*

**Physics**

Dry air will break down if the electric field exceeds about 3.0 × 106 V/m. What amount of charge can be placed on a capacitor if the area of each plate is 6.7 cm2?
*February 28, 2013*

**physics**

The two plates of a capacitor hold +3200 µC and -3200 µC of charge, respectively, when the potential difference is 700 V. What is the capacitance?
*February 28, 2013*

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