Wednesday

August 20, 2014

August 20, 2014

Total # Posts: 126

**Chemistry**

Calculate the value of the standard enthalpy change for each of the following reactions (standard enthalpy for Na2SO4(s) is -1375.653 kj/mole): a) 4HBr(g) + O2(g) = 2H2O(I) + 2Br(I) b) 2Na(OH)(s) + SO3(g) = Na2SO4(s) + H2O(g) c) CH4(g) + 4CI2(g) = CCI4(I) + 4HCI(g) d) Fe2O3(s...
*July 3, 2014*

**Chemistry**

Using standard enthalpies information, calculate the standard enthalpy change for this reaction: a) (thermite reaction) 2Al(s) + Fe2O3(s) = Al2O3(s) + 2Fe(s) b) Mg(OH)2(s) = MgO(s) + H2O(I) c) N2O4(g) + 4H2(g) = N2(g) + 4H2O(g) d) SiCl4(I) + 2H2O(I) = SiO2(s) + 4HCI(g)
*July 3, 2014*

**Chemistry**

Given the Data: N2(g) + O2g) = 2NO(g) delta H = 180.7kj, 2NO(g) + O2(g) = 2NO2(g) delta H = 0113.1kj, 2N2O(g) = 1N2(g) + O2(g) delta H = -163.2kj. Using Hess’s Law calculate delta H for the reaction: N2O(g) + NO2(g) = 3NO(g)
*July 3, 2014*

**Chemistryq**

A cylinder of gas contains 96.0 g of oxygen gas, O2. If the volume of the cylinder is 9.00 liter and at 25.0 degrees C. What is the pressure of O2 in the cylinder?
*July 3, 2014*

**Chemistry**

A solution of hydrogen peroxide, H2O2, is titrated with potassium permanganate, KMnO4, according to the following equation: 5H2O2 + 2KMnO4 + 3H2SO4 = 5O2 + 2MnSO4 + 8H2O + K2SO4. It requires 46.0 mL of 0.145 Mol/L KMnO4 to titrate 50.0 mL of the solution of H2O2. What is the ...
*July 3, 2014*

**Chemistry**

1. Nitric acid is produced via the following equation: 3 NO2 + H2O = 2HNO3 + NO. How many grams of NO2 are required to produce 7.5 grams of HNO3?
*June 17, 2014*

**Physics **

Merry go round is push by a 100 kg man Radius is 2 m how much force is exerted. Maximum force in newtons
*June 12, 2014*

**Algebra**

Using the formula h=-16^2+vt+s Answer the question: A rocket is shot upward off a 25 foot high balcony with an initial velocity of 96 feet per second. How many seconds will it take until the rocket hits the ground?
*May 16, 2014*

**Chemistry**

22mL of hydrogen was collected over wter at 19C and 745mmHg. What mass of magnesium is reacted (1:1 mole ratio)
*April 20, 2014*

**Algebra, URGENT!! HELP!**

Rewrite the following as a perfect square: 144b^18
*January 27, 2014*

**Probability**

an urn contains 40 red chips and sixty white chips. six chips are drawn out and discarded, and a seventh is drawn. what is the probability that the seventh chip is red?
*September 25, 2013*

**Science**

Can a hypotheses be accepted as true after one test?
*September 3, 2013*

**English**

Sorry, did not know my brother had gotten on here too.
*September 3, 2013*

**English**

I think direct object?
*September 3, 2013*

**Physics**

When a 81.0 kg. person climbs into an 1400 kg. car, the car's springs compress vertically 1.5 cm. What will be the frequency of vibration when the car hits a bump? (Ignore damping.)
*July 26, 2013*

**Physics**

Two physical pendulums (not simple pendulums) are made from meter sticks that are suspended from the ceiling at one end. The sticks are uniform and are identical in all respects, except that one is made of wood (mass = 0.17 kg) and the other of metal (mass = .85 kg). They are ...
*July 24, 2013*

**programming**

You have the final sales figures for the four quarters in 2010 for Bennets Used Auto Sales, and you are to design a program that asks for the sales figures, computes the total sales for the year, and calculates and displays the average quarterly sales for the year. using ...
*June 1, 2013*

**Physics**

1/4h
*April 23, 2013*

**Chemistry**

Four ice cubes at exactly 0 degrees Celsius having a total mass of 55.0g are combined with 120g of water at 77 degrees Celsius in an insulated container. If no heat is lost to the surroundings, what will be the final temperature of the mixture?
*January 22, 2013*

**physics**

A 1.13 × 103 kg car accelerates uniformly from rest to 10.6 m/s in 3.22 s. What is the work done on the car in this time interval? Answer in units of J
*December 16, 2012*

**Reading**

im reading this book called across five aprils. I need another quote from the book to go with my essay. i need a good quote from the part were Jethro finds his couisn, Eb, in the woods. Eb is a deserter. Jethro wants to get him help........ Do you have any suggestions?
*December 10, 2012*

**Science**

A car of mass 1190 kg is on an icy driveway inclined at an angle of 28◦ If the incline is frictionless, what is the acceleration of the car?
*November 14, 2012*

**physics**

A soccer ball kicked with a force of 14.8 N accelerates at 6 m/s2 to the right. What is the mass of the ball?
*November 13, 2012*

**physcis**

A soccer ball kicked with a force of 14.8 N accelerates at 6 m/s2 to the right. What is the mass of the ball?
*November 13, 2012*

**physcis**

A soccer ball kicked with a force of 14.8 N accelerates at 6 m/s2 to the right. What is the mass of the ball?
*November 13, 2012*

**physics**

The net external force on the propeller of a 3.9 kg model airplane is 6.8 N forward. What is the acceleration of the airplane?
*November 13, 2012*

**physics**

The net external force on the propeller of a 3.9 kg model airplane is 6.8 N forward. What is the acceleration of the airplane?
*November 13, 2012*

**Chemistry**

Find the thetrical formula for .012 mol of H20, .0056 moles of Cl2 and .0060 of copper with a formula like this CuCl*H20 *=point in center
*September 24, 2012*

**Chemistry**

A 28.4288 g sample of impure magnesium car- bonate was heated to complete decomposition according to the equation MgCO3(s) ! MgO(s) + CO2(g) . After the reaction was complete, the solid residue (consisting of MgO and the original impurities) had a mass of 16.0467 g. Assum- ing...
*September 21, 2012*

**Chemistry**

I have 3 I don't understand how to do. A 33.2 g of iron ore is treated as follows. The iron in the sample is all converted by a series of chemical reactions to Fe2O3. The mass of Fe2O3 is measured to be 12.3 grams. What was the percent iron in the sample of ore? Answer in ...
*September 21, 2012*

**Social Studies**

The Grange (short form) or the National Grange of the Order of Patrons of Husbandry (long form).
*August 17, 2012*

**writing**

It would help if we knew why you had to reword the sentences. Are you trying to make them more concise? More specific? Reach a certain audience (grade level)?
*August 17, 2012*

**physics**

The answer is 3 but you need to know why! (Think about things like friction, wind, etc. which are forms of resistance and how fast a minute hand moves around the clock...does it ever change speed?)
*August 17, 2012*

**chem**

Figure out how much each compound weighs. Each side of the equation must have the same weight. So if you have 1.5x10^2 kg of aspirin, how much salicylic acid and acetic anhydride must you have to make that much PLUS have the required amount of HC2H3O2? For part B, multiple the...
*August 17, 2012*

**geometry**

Remember that similar polygons are ones that have the same ratio for all the sides. So in order to have an area 9 times as great the sides must be 3 times as long (area is linear x linear, or 3 x 3 = 9). (Check your answer--draw a picture if it helps!)
*August 17, 2012*

**Economics**

GDP = C + I + G + (X - M) Where: C = household consumption expenditures / personal consumption expenditures I = gross private domestic investment G = government consumption and gross investment expenditures X = gross exports of goods and services M = gross imports of goods and...
*August 17, 2012*

**Geometry**

Suppose J is between H and K. Use the Segment Addition Postulate to solve for x. Then find the length of each segment. HJ=2x+5 JK=3x-7 KH=18
*August 13, 2012*

**Physics**

Thanks a lot. For B the answer was 6.83x10^-4 deg.
*April 28, 2012*

**Physics**

A plumb bob (a mass m hanging on a string) is deflected from the vertical by an angle θ due to a massive mountain. A) Make an estimate of the mass of Mt. Everest, assuming it has the shape of a cone 3910 m high and base of diameter 3910 m. Assume its mass per unit volume ...
*April 28, 2012*

**Physics**

m1v1 = (0.0146)(v1) (vertically downward is neg direction) v1 = √2gh (where h = 1.23) v1 = 4.91 m/s m1v1 = (0.0146)(4.91) = - 0.0717 kg-m/s (Momentum Before Floor) m2v2 = (0.0146)v2 (vertically upward) v2 = √2gh (where h=.665) v2 = 3.61 m/s m2v2 = (0.0146)(3.61...
*March 26, 2012*

**Physics**

A 14.6-g marble is dropped from rest onto the floor 1.23 m below. If the marble bounces straight upward to a height of 0.665 m, what is the magnitude of the impulse delivered to the marble by the floor. If the marble had bounced to a height of 0.884 m, what would the magnitude...
*March 26, 2012*

**Math**

Which represents the type of sequence: 12, 22, 30, 36, 41, …? neither arithmetic nor geometric both arithmetic and geometric arithmetic geometric
*March 10, 2012*

**Physics**

A 73.3 kg man steps out a window and falls (from rest) 1.09 m to a sidewalk. What is his speed just before his feet strike the pavement? 4.62 m/s If the man falls with his knees and ankles locked, the only cushion for his fall is a 0.510 cm give in the pads of his feet. ...
*March 5, 2012*

**physics**

Cliff and Will are carrying a uniform 2.0m board of mass 69kg. Will is supporting the board at the end while cliff is 0.6m from the other end as shown in the following figure. Cliff has attached his lunch to his end of the board, and the tension in the string supporting the ...
*February 23, 2012*

**physics**

What is the rotational speed of the minute hand on a clock? Convert from rad/s to rev/s
*February 23, 2012*

**physics**

A 50 gram ball enters a a pendulum with mass 200 g. The pair then swings up to a height of 10 cm. Find the velocity at which the pair move immediately after the collision. Your answer is incorrect. 1.4 m/s Find the initial velocity of the ball before the collision.
*February 23, 2012*

**physics**

A car of mass 907 kg coasts on a level road, starting with an initial speed of 14.2 m/s and coming to rest 15.2 s later. Find the frictional force acting on the car.
*February 20, 2012*

**physics**

The Earth orbits the Sun once per year.What is the centripetal force keeping the Earth in orbit? T = 1 year (convert to seconds) r = 1.5e+11 meters m = 6e+24 kg
*February 11, 2012*

**physics**

Phrank (36.4kg) runs at 2.2 m/s and jumps onto a large stationary skateboard (2.3kg) on which Phrancine (22.7kg) is sitting. After the collision, Phrank, Phrancine, and the skateboard move at 1.3 m/s. Find the momentum before and after the collision along with the percent ...
*February 11, 2012*

**physics**

A .145kg baseball is thrown at 40 m/s (~89.5mph). What is the momentum of the baseball?
*February 11, 2012*

**physics**

A woman with a mass of 56 kg runs at a speed of 8 m/s and jumps onto a giant 30 kg skateboard initially at rest. What is the combined speed of the woman and the skateboard?
*February 11, 2012*

**physics**

A coach is hitting pop flies to the outfielders. If the baseball (mass = 145 g) stays in contact with the bat for 0.08 s and leaves the bat with a speed of 75 m/s, what is the average force acting on the ball?
*February 11, 2012*

**physics**

A 610 kg satellite orbits at a distance from the Earth's center of about 5.3 Earth radii. What gravitational force does the Earth exert on the satellite?
*February 4, 2012*

**physics**

A satellite orbits at a distance from the Earth's center of about 4.40 Earth radii and takes 13.0 hours to go around once. What distance (in meters) does the satellite travel in one day?
*February 4, 2012*

**Physics**

An explorer is caught in a whiteout (in which the snowfall is so thick that the ground cannot be distinguished from the sky) while returning to base camp. He was supposed to travel due north for 5.7 km, but when the snow clears, he discovers that he actually traveled 8.4 km at...
*January 21, 2012*

**Chem 30**

1) Suppose the mass of the NaOH used in a reaction was doubled. What would you expect to happen to the heat given off by the reaction? Explain your answer. 2)Again, suppose the mass of the NaOH used in a reaction was doubled. What would you expect to happen to the heat given ...
*January 3, 2012*

**Honors Chemistry**

What is the Lewis dot diagram for C2Cl2?
*December 6, 2011*

**Calculus **

Solve the exponential equation for t. Round your answer to three decimal places if necessary. e^(0.08t)=4 Please show work
*November 6, 2011*

**Calculus **

Differentiate f(x)=(x^(3)-8)^(2/3) Please Show Work
*November 6, 2011*

**Calculus **

Find The Derivative y=5x^(2)e^(3x) Please Show Work
*November 6, 2011*

**Calculus **

Find The Derivative y= 9e^(x)/ 2e^(x)+ 1 Please Show Work
*November 6, 2011*

**Calculus **

Graph f(x) = 4^(x - 1) Please show work
*November 6, 2011*

**Calculus **

Differentiate. f(x)= -8e^(5x)
*November 6, 2011*

**Physics**

What net external force is required to give a 35.7 kg suitcase an acceleration of 2.8 m/s2 to the right? Answer in units of N.
*September 19, 2011*

**Trig**

A soccer goal is 24 feet wide. Point A is 40 feet in front of the center of the goal. Point B is 40 feet in front of the right goal post. Which angle is larger A or B? How much larger?
*August 28, 2011*

**spanish**

Change the following constructions to an adjetivo posesivo and noun according to the example: Example: la mesa de ella su mesa 1. el gato de Juan y María 2. las sillas de ti 3. el hermano de mí 4. la computadora de tu y yo 5. la mesa de usted 6. la mesa de ...
*June 23, 2011*

**spanish1**

If you could tell me the right answers, and an explanation why each is right thatd be great! thank you 1. A boot verb is irregular A in four subjects B in two subjects C in three subjects D in one subject E in five subjects F in all subjects 5. ¿Cómose dice "...
*May 20, 2011*

**geometry**

Triangles ABC and PQR are similar with m angle A = m angle P and m angle B = m angle Q. If AB, BC, and AC are 3, 4, and 5 ft long respectively and QR is 10 ft, find PQ.
*May 6, 2011*

**physics**

Search: The drawing shows a collision between two pucks on an air-hockey table. Puck A has a mass of 0.029 kg and is moving along the x axis with a velocity of +5.5 m/s. It makes a collision with puck B, which has a mass of 0.049 kg and is initially at rest. After the ...
*April 20, 2011*

**PPPPPhysicssssss**

answer is 9.33×10−2 m
*March 31, 2011*

**English **

I have to compare and constrast the funeral orations of Mark Antony and Marcus Brutus. What I need is a thesis statement for this paper and everything I come up with sounds lame. I'm not getting the message across. Could you help me?
*March 23, 2011*

**English **

I have to compare and constrast the funeral orations of Mark Antony and Marcus Brutus. What I need is a thesis statement for this paper and everything I come up with sounds lame. I'm not getting the message across. Could you help me?
*March 23, 2011*

**college physical science**

Convert units 120mph equals 120*5280*(1/60)= 10560 ft/min a=ft/min/min a=10560/15= 704ft/min^2 F=ma F=704*200000=140800000 lb*ft/min^2
*February 8, 2011*

**English **

Which is correct? You should never believe ( these kind, these kinds ) of stories. Think the correct answer is ( these kinds)
*January 27, 2011*

**English **

Which is correct? You should never believe ( these kind, these kinds ) of stories. Think the correct answer is ( these kinds)
*January 27, 2011*

**History Help Please!!!**

Ms. Sue, I don't think that is what he wants. He seems to be asking for a particular document.
*December 16, 2010*

**History Help Please!!!**

i'm writing a paper on the Bolivarian Alternative for the Nations of Our America and I need to tie in a leaked U.S. document that referred to particular countries called the "Axis of Mischief." I can't find one, could you please help??
*December 16, 2010*

**chemistry**

.12
*November 23, 2010*

**chemistry**

A buffer solution contains 0.200 M NH3 and 0.250 M NH4Cl. What is the pH of the buffer solution after the addition of 10.0 mL of 0.100 M NaOH to 50.0 mL of the buffer? Kb for NH3 is 1.8 x 10-5.
*October 26, 2010*

**6th grade**

what is 3/10 divided by 13/14
*October 20, 2010*

**science**

D is the correct answer. Convert to 10^15 and then add. Significant digits for addition key on the decimal point location, so 3.6018 x 10^15 is correct.
*September 12, 2010*

**9th grade Math**

what is the probabilty of spinning a divisor of 12?
*August 18, 2010*

**math**

In 2000 1/3 of all births in the US were to unmarried women. IF there were 1,352,938 births to unmarried women then how many births were in 2000?
*August 18, 2010*

**english**

Is Where to? a complete sentence or a fragment?
*June 8, 2010*

**11th grade**

Molarity= Moles of solute/Liters of solvent Conversions (Dimensional Analysis) You always start with whatever unit you're given and multiply that by whatever new unit you are looking for divided by the amount of old units to make one of the new units.
*May 27, 2010*

**Geometry**

Need help finding dimensions of a triangular prism. It has a volume of 900 cubic inches. Two of the dimensions are consecutive even numbers. Two of the dimensions are multiples of 5. All the dimensions are less than 16, but greater than 6. All lengths are different. The base ...
*May 20, 2010*

**Geometry**

We have a triangular prism that has the following characteristics. It has a volume of 360 cubic inches. The base of the triangle is twice the height of the triangle. The difference between the height of the prism and the height of the triangle is 4 inches. The height of the ...
*May 20, 2010*

**Geometry**

A rectangular prism has the following characteristics. It has a volume of 71 cubic inches. The sum of the three lengths is 14. The width is 2 less than the length. The length is 5 more than the height. What are the dimensions of this rectangular prism? Need help on finding ...
*May 20, 2010*

**Geometry**

I need to find the dimensions of this rectangular prism. It has a volume of 108 cubic inches. The length and width of the base are identical. The height is half of the length. Can you help explain how to do this given this information?
*May 20, 2010*

**us history**

Why do some people consider Andrew Jackson a tyrant?
*May 18, 2010*

**chemistry**

A 4.30 g nugget of pure gold absorbed 293 J of heat. The initial temperature was 23.0°C. What was the final temperature?
*May 10, 2010*

**chemistry**

The temperature of a sample of water increases from 20.7°C to 45.7°C as it absorbs 5675 J of heat. What is the mass of the sample?
*May 10, 2010*

**chemistry**

How much heat is evolved when 269 g of ammonia gas condenses to a liquid at its boiling point?
*May 10, 2010*

**math**

the length of a rectangle is 3cm more than twice the width. the perimeter is 84cm. find the length Please show me the steps on how you get the answer. Thanks
*April 7, 2010*

**Math**

the length of a rectangle is 3cm more than twice the width. the perimeter is 84cm. find the length
*April 7, 2010*

**science**

guys im really depressed. i need this answer too
*January 30, 2010*

**algebra**

how do i factor 8m^2-6mn-9n^2
*November 4, 2009*

**5th grade english**

How do I do this. Read the journal entry about a field trip. Cross out any extra information. The underline the text where it should be divided into two or more sentences. I liked using the heat lamp in the science activity it showed how the polar bear's black skin helps ...
*March 30, 2009*

**Economics (Equilibrium)**

Suppose fred ethel ricky and lucy have the following demand functions for a public good Qf= 40-1/2p Qe= 20-p Qr= 30-1/2p Ql= 50-p The good can be produced at a constant cost of 5 dollars Calculate the Lindahl Equilibrium I know that the lindhal is the vertical summation of ...
*March 26, 2009*

**Biology**

Increasing what in a plant cell will increase energy production? I was thinking glucose, water, or sunlight. But the thing is we are talking about changing something within the cell. Anyone want to chime in on this? Thanks!
*February 20, 2009*