Sunday

October 26, 2014

October 26, 2014

Total # Posts: 4,038

**Chemistry**

The standard molar Gibbs free energy of formation of NO2 (g) at 298 K is 51.30 kJ · mol −1 and that of N2O4 (g) is 97.82 kJ · mol −1 . What is the equilibrium constant at 25 ◦ C for the reaction 2 NO2(g) <=> N2O4(g) ?
*October 14, 2012*

**Physics**

When a spacecraft travels from the Earth to the Moon, both the Earth and the Moon exert a gravitational force on the spacecraft. Eventually, the spacecraft reaches a point where the Moon's gravitational attraction overcomes the Earth's gravity. How far from the Earth&#...
*October 13, 2012*

**stats**

blood cholesterol level of all men age 20-24 follows N(188,41) where the units for the men and standard deviation are in mg/dl. what is the probability that the sample mean takes a value between 185 and 191 if we sample 1000 men
*October 12, 2012*

**Science**

When a car slams on its brakes what provides friction that helps the car stop? What kind of energy is produced?
*October 11, 2012*

**Maths Percentage (6th Grade)**

David has $5 in his wallet. This was 10% of the amount that he received from his mother. Find the total amount of money that David received from his mother. 35% of the number of books Ibrahim owns are fiction boos, find: a.) the total number of books he owns. b.) the number of...
*October 11, 2012*

**Math**

ok stuck again. Got everything else calculated, but why is the median the best choice? is it because 19 is the closest to the mean, 16.75 ? Can you explain??
*October 10, 2012*

**pre-ap Algebra 2**

write a polynomial function f of least degree that has the rational coefficients, a leading coefficient of 1, and the given zeros. Given zeros: -2,2,-1,3, sqrt 11
*October 10, 2012*

**physics**

Two mountain climbers are working their way up a glacier when one falls into a crevasse. The icy slope can be considered frictionless. Sue's (the one who fell) weight is pulling Paul up the 45 degree slope. If Sue's mass is 66 kg and if she falls 2 min 10 s (starting ...
*October 9, 2012*

**Integrated 2**

Aaron has 20 dimes and nickels which together total is 1.40 how many of each does he have
*October 9, 2012*

**Physics**

Two pole-vaulters just clear the bar at the same height. The first lands at a speed of 8.50 m/s, and the second lands at a speed of 8.80 m/s. The first vaulter clears the bar at a speed of 1.50 m/s. Ignore air resistance and friction and determine the speed at which the second...
*October 9, 2012*

**Physics**

This doesn't give me the correct answer according to the assignment program :/
*October 9, 2012*

**Physics**

A pendulum consists of a small object hanging from the ceiling at the end of a string of negligible mass. The string has a length of 0.88 m. With the string hanging vertically, the object is given an initial velocity of 1.7 m/s parallel to the ground and swings upward on a ...
*October 9, 2012*

**Finite**

Assume that the coin is weighted so that Pr[H] = [ 1/11], and that it is flipped 9 times. The random variable X is defined as the number of heads in the 9 flips. What is E[X]?
*October 8, 2012*

**Finite**

Assume that the box contains balls numbered from 1 through 28, and that 3 are selected. A random variable X is defined as 1 times the number of odd balls selected, plus 2 times the number of even. How many different values are possible for the random variable X? I know that is...
*October 8, 2012*

**Physics**

An American bald eagle heads south at 5.5 m/s, but encounters a wind blowing from the east at 1.9 m/s. By how many degrees will she be blown o course?
*October 8, 2012*

**Chemistry**

One mole of carbon (12.0 g) in the form of crystalline graphite is burned at 25 ◦ C and 1.000 atm pressure to form CO2(g). All of the heat produced is used to heat a 4560 g bath of liquid water, originally at 25 ◦ C. What is the ﬁnal temperature of the water...
*October 7, 2012*

**Chemistry**

Given the standard heats of reaction Reaction ∆H0 M(s) + 2 X2(g) → MX4(g) −123.7 kJ/mol X2(g) → 2 X(g) +297.3 kJ/mol M(g) → M(s) −25.1 kJ/mol calculate the average bond energy for a single M- X bond
*October 7, 2012*

**Chemistry**

The standard enthalpy of formation of Mn2O3 is −962.3 kJ/mol. How much heat energy is liberated when 4.7 grams of manganese are oxidized by oxygen gas to Mn2O3 at standard state conditions? Answer in units of kJ
*October 7, 2012*

**physics**

A hot air balloon descends with an overall velocity of 4.2 m/s at an angle of 36.8⁰ below the horizontal. what is the horizontal velocity of the balloon?
*October 7, 2012*

**physics**

A cup of coffee is on a table in an airplane flying at a constant altitude and a constant velocity. The coefficient of static friction between the cup and the table is 0.18. Suddenly, the plane accelerates forward, its altitude remaining constant. What is the maximum ...
*October 3, 2012*

**physics**

A 6.01-kg box is sliding across the horizontal floor of an elevator. The coefficient of kinetic friction between the box and the floor is 0.291. Determine the kinetic frictional force that acts on the box when the elevator is (a) stationary, (b) accelerating upward with an ...
*October 3, 2012*

**Math**

Has memory chip capacity's growth been exponential? How much longer is the exponential growth likely to continue? Explain.
*October 2, 2012*

**Math**

Divide 64 bundles of newspapers into two groups so the ratio is 3 to 5.
*September 29, 2012*

**physics**

Calculate the velocity needed for an object starting at the Earth's surface to just barely reach a satellite in a geosynchronous orbit. Ignore air drag and assume the object has a speed of zero when it reaches the satellite. (The orbital radius of a satellite in a ...
*September 27, 2012*

**Science**

True or false: light travels in straight lines if the medium it travels doesn't change
*September 26, 2012*

**math**

When I am rounded to the nearest hundred, I am 3,300. The diiference between my ones and thousands digits is 1. My tens digit is the same number as my ones digit. I can be two different numbers. Who am I?
*September 26, 2012*

**math**

Tks, Ms. SUE!
*September 26, 2012*

**Chemistry**

Thank you for answering this below Dr Bob
*September 26, 2012*

**Chemistry **

What volume of 0.200M of aqueous solution of formic acid, a weak monoprotic acid (KA = 1.78x10-4) and 0.200M aqueous solution of NaOH would you mix to prepare a 500mL of a buffer solution of pH = 4.0. I know I need to use the H-H equation, I'm just not sure what I plug in ...
*September 26, 2012*

**chemistry**

q= 4.184(42.3)(10.2-21.9) = -2070.70 J -2070.70J/6.60g KCl = -313.74 J/g -313.74 J/g(74.55g/ 1 mol KCl)= -23389.32J/mol -23.4 kJ/mol Is this correct?
*September 26, 2012*

**chemistry**

KCl(s) → K+(aq) + Cl‾ (aq) Solid KCl dissolves as shown in the above equation. A 6.60 g sample of KCl was dissolved in 42.3 g of water. The initial temperature of the water was 21.90°C. After the compound dissolved, the temperature of the water was 10.20°C...
*September 26, 2012*

**Chemistry **

What volume of 0.200M of aqueous solution of formic acid, a weak monoprotic acid (KA = 1.78x10-4) and 0.200M aqueous solution of NaOH would you mix to prepare a 500mL of a buffer solution of pH = 4.0.
*September 26, 2012*

**algebra**

solve the linear system from problem 1 using elimination 4x-y=5 4x+4y=-4
*September 25, 2012*

**Physics**

A plane drops hamper of medical supplies from a height of 2740m during a practice run over the ocean. The plane's horizontal velocity was 126m/s at the instant the hamper was dropped. What is the magnitude of the overall velocity of the hamper at the instant it strikes the...
*September 24, 2012*

**Physics**

A person is standing on a spring bathroom scale on the ﬂoor of an elevator which is moving up and slowing down at the rate of 2.73 m/s^2. The acceleration of gravity is 9.8 m/s^2. If the person’s mass is 75.2 kg, what does the scale read? Answer in units of n
*September 24, 2012*

**Physics**

a 96.4kg boxer has his first match in the canal zone with gravitational acceleration 9.782m/s^2 and his second match at the north pole with gravitational acceleration 9.832m/s^2. What is his mass in the canal zone? answer in units of kg
*September 24, 2012*

**Physics**

A boat moves through the water with two forces acting on it. One is a 2304N forward push by the motor on the propeller, and the other is a 2154N resistive force due to the water around the bow. What is the acceleration of the 1293kg boat? Answer in units of m/s^2.
*September 24, 2012*

**Physics**

A large uniform chain is hanging from the ceiling, supporting a block of mass 48kg. The mass of the chain itself is 15 kg, and the length of the chain is 2.6 m. The acceleration of gravity is 9.81 m/s^2 Find the tension in the chain at the point where the chain is supporting ...
*September 24, 2012*

**Physics**

When a 117 N bag of nails hangs motionless from a single vertical strand of rope, how much tension is exerted in the strand? Answer in units of N
*September 24, 2012*

**Physics**

The tension in a string from which a 6 kg object is suspended in an elevator is equal to 61 N. What is magnitude of the acceleration a of the elevator? The acceleration of gravity is 9.8 m/s^2. Answer in units of m/s^2
*September 24, 2012*

**Physics**

A person weighing 0.6 kN rides in an elevator that has a downward acceleration of 2.3 m/s^2. The acceleration of gravity is 9.8 m/s^2. What is the magnitude of the force of the elevator ﬂoor on the person? Answer in units of kN
*September 24, 2012*

**math**

I got 1:633,600 Is that correct?
*September 22, 2012*

**math**

Find the scale ratio of this map: 1 inch on the map represents 10 miles
*September 22, 2012*

**instrumental analysis**

How long would it take to discharge a 0.026 microFarad capacitor to 6.4 % of its full charge through a resistance of 1.7 MOhm?
*September 21, 2012*

**Math**

Thanks!
*September 20, 2012*

**Math**

How many liters of oil are required to supply the electrical energy needs of an average home for a month? Energy released by burning 1 liter of oil= 1.2 x 10(7th power) Electrical energy used in an average home daily 5 X 10 (7th power) I got 125 liters. Is that correct?
*September 20, 2012*

**Math**

Thanks! I have the same reasoning.
*September 20, 2012*

**Math**

Can you help me with this question? Could a person walk across the United States (New York to California) in a year? If not, about how long will it take? Explain your reasoning.
*September 20, 2012*

**Math**

Thank you! That helped.
*September 20, 2012*

**Math**

How did you get .253m? Wouldn't you multiply by 100?
*September 20, 2012*

**Math**

Can You help me with this question? The distance from the earth to the sun is about 1.5 X 10^8 km, while the distance from the earth to the moon is about 3.8 X 10^5 km. If a scale model of the solar system is constructed so that the distance from the Earth to the Sun is 100 ...
*September 20, 2012*

**Math**

What is the integral: 1/root(2x-x^2)
*September 20, 2012*

**Maths**

What is the integral of: 1/root(2x-x2)
*September 20, 2012*

**Maths**

*This is not an answer* Thanks Steve that really helps!!! *This is not an answer*
*September 19, 2012*

**Maths**

Integral of 1/root(2x-x^2)dx
*September 19, 2012*

**Chemistry**

The solubity of KNO3 at 0 is 20 g and CuSO4.5H2O at 0 is 10 g. i'm lost as to how this pertains to the answers.
*September 18, 2012*

**Chemistry**

2) To the solution in problem 1 (d) at 100 degrees celsius, 10g of water are added, and the solution is cooled to 0 degrees celsius... (problem 1d: the number of grams of water required to dissolve a mixture containing 15 g KNO3 and 3.5 g CuSO4 * 5 H20, assuming that the ...
*September 18, 2012*

**literature**

someone took away children before they were grown and they cried because they were being taken away
*September 18, 2012*

**probability and statistics**

A 0.1μm diameter drop of 1mM protein solution is introduced into pure water centered at x. Assume proteins diffuse randomly by “stepping” a distance 0.1μm every millisecond. a. What is the density at x after 1 minute? b. How many protein molecules are there...
*September 18, 2012*

**geometry**

Y is a point on HR with HO=(19x) miles and OR=48 miles. If HR=(27x) miles, find HO (in miles)
*September 16, 2012*

**Physics**

While warming up in her tryout as a pitcher for the Montwood softball team, Anabel Parga throws a softball horizontally with a speed of 22m/s. a. If home plate is 19m away, how far should the softball fall from its initial straight-line path on its way to home plate? b. The ...
*September 16, 2012*

**math**

how many combination of coins make 2.00 when given 2 quarters, 5 dimes and 18 nickels?
*September 15, 2012*

**physics**

An automobile accelerates from rest at 1.3m/s^2 for 19s. The speed is then held constant for 23s, after which there is an acceleration of -0.9m/s^2 until the automobile stops. What total distance was traveled? Answer in units of km.
*September 14, 2012*

**Physics**

Highway safety engineers build soft barriers so that cars hitting them will slow down at a soft rate. A person wearing a safety belt can withstand an acceleration of 300m/s^2. How thick should barriers be to safely stop a car that hits the barriers at 92.8km/h? Answer in units...
*September 14, 2012*

**physics**

Highway safety engineers build soft barriers so that cars hitting them will slow down at a soft rate. A person wearing a safety belt can withstand an acceleration of 300m/s^2. How thick should barriers be to safely stop a car that hits the barriers at 92.8km/h? Answer in units...
*September 14, 2012*

**physics**

An airport has runways only 136m long. A small plane must reach a ground speed of 39m/s before it can become airborne. What average acceleration must the plane's engines provide if it is to take off safely from its airport? Answer in units of m/s^2.
*September 14, 2012*

**Physics**

The barrel of a rifle has a length of 0.916m. A bullet leaves the muzzle of a rifle with a speed of 621m/s. What is the acceleration of the bullet while in the barrel? A bullet in a rifle barrel does not have a constant acceleration, but constant acceleration is to be assumed ...
*September 14, 2012*

**physics**

A subway train starting from rest leaves a station with a constant acceleration. At the end of 7.94s, it is moving at 12.3864m/s. What is the train's displacement in the first 5.57388s of motion? Answer in unites of m.
*September 14, 2012*

**Physics**

A tennis ball with a speed of 14m/s is moving perpendicular to a wall. After striking the wall, the ball rebounds in the opposite direction with a speed of 11.41m/s. If the ball is in contact with the wall for 0.0112s, what is the average acceleration of the ball while it is ...
*September 14, 2012*

**Math**

Multiply & write in simplest form: The mississippi river is about 23/25 the length of the missouri river. If the missouri river is 2,540 miles long, how long is the mississippi river? Thanks
*September 12, 2012*

**Physics**

Initially, a particle is moving at 5.40 m/s at an angle of 37.2° above the horizontal. Two seconds later, its velocity is 6.10 m/s at an angle of 55.0° below the horizontal. What was the particle's average acceleration during these 2.00 seconds in the x-direction ...
*September 10, 2012*

**Physics**

A place kicker must kick a football from a point 29.0 m (= 31.7 yd) from the goal, and the ball must clear the crossbar, which is 3.05 m high. When kicked, the ball leaves the ground with a speed of 17.8 m/s at an angle of 41.0o to the horizontal. By how much does the ball ...
*September 10, 2012*

**english**

yes yes its correct
*September 7, 2012*

**chemistry**

potassium chlorate will decompose to produce potassium chloride and oxygen gas . if you begin with 45 kg of potassium chlorate, how many liters of oxygen gas measured at stp might you expect to produce from this reaction
*September 7, 2012*

**Science**

What is the purpose of a control group in an experiment? a. To serve as a standard of comparison or b. To be the group exposed to changes in the manipulated variable
*September 6, 2012*

**Math**

Convert 60,000 BTU/hr to in.cubic feet/minute.
*September 3, 2012*

**math**

setup an equation or expression to model the situation below: find the shortest distance from the point (2,4) to the curve y=4x^3+1
*September 3, 2012*

**math**

setup an equation or expression to model the situation: a rectangle that would fit inside of the curve y=-x^2+8
*September 3, 2012*

**math**

setup an equation or expression to model the situation below: in one year, sales for a company increase at a constant rate. after two months, the company sells 12,500 products, and after 8 months, the company sells 30,000 products. If the constant rate of increase continues, ...
*September 3, 2012*

**math**

setup an equation or expression to model the situation below: what is the volume of a box that can be created from a sheet of metal that measures 12 inches by 30 inches? assumer there is no top to the box.
*September 3, 2012*

**Econ**

Explain the apparent paradox that saving money if good for the individual but may be bad for the economy. How is this relevant to public policy today?
*September 1, 2012*

**chemistry**

94. mL
*August 31, 2012*

**Health**

What is the Affordable Care Act? A. A program that covers diet counseling for people who are at higher risk for chronic diseases like diabetes and high blood pressure. B. A program that allows people who are at higher risk for chronic diseases to gain free memberships to gyms ...
*August 30, 2012*

**Health**

What are other factors that contribute to being overweight and obese besides diet and behavior? A. Personality and temperament B. Physical fitness and athletics C. Environment and genetic factors D. Smoking and drinking alcohol I think it should be all of them, but that's ...
*August 30, 2012*

**Health**

Thanks again(:
*August 30, 2012*

**Health**

What steps should you take to watch your diet? A. Follow a healthy and realistic eating pattern B. Keep your eating patterns consistent C. Eat breakfast everyday D. All of the above d?
*August 30, 2012*

**Health**

Obesity can cause a person to develop what type of conditions? A. Head, back, and neck pains B. Increased energy and reduced stress C. Low blood pressure and type I diabetes D. High blood pressure and Type 2 diabetes A?
*August 30, 2012*

**Health**

Thanks Ms.Sue :))
*August 30, 2012*

**Health**

What is the best way to lose weight and keep the weight off? A. By losing ½ to 2 pounds a week B. By losing 3 to 5 pounds a week C. By losing 6 to 8 pounds a week D. By losing 10 or more pounds a week A?
*August 30, 2012*

**Health**

What does the U.S. government use to estimate a person’s body weight status? A. Scale B. Ruler C. Body mass index D. Health related illnesses c?
*August 30, 2012*

**Health**

Someone please help?????
*August 30, 2012*

**Health**

Adults and children should limit their intake of sodium because? A. Keeping blood pressure in the normal range reduces an individual’s risk of cardiovascular disease, conges¬tive heart failure, and kidney disease. B. Keeping blood pressure in the normal range reduces ...
*August 30, 2012*

**Health**

According to the government’s My Plate program, half of our plate should have? A. Pasta and breads B. Seafood C. Fruits and vegetables D. Protein and desserts a? or c? idk:/
*August 30, 2012*

**Health**

Americans should drink ________ instead of sugary drinks? A. Energy drinks B. Whole milk C. Water D. Diet soda I put c?
*August 30, 2012*

**Health**

Helllp pleease:(
*August 30, 2012*

**Health**

What are the four basic food safety principles that work together to reduce the risk of food borne illnesses? A. Wash, Cook, Eat, Clean B. Clean, Separate, Cook, Chill C. Clean, Cook, Store, Disinfect D. None of the above d?
*August 30, 2012*

**Health**

Please help:(
*August 30, 2012*

**Health**

________ physical activity and ________ time spent in sedentary behaviors. A. Reduce; increase B. Reduce; reduce C. Increase; reduce D. Increase; increase
*August 30, 2012*

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