Friday

January 20, 2017
Total # Posts: 1,324

**Chemistry**

Hydrogen peroxide can be prepared by the reaction of barium peroxide with sulfuric acid according to BaO2(s)+ H2SO4(aq)---> BaSO4(s)+ H2O2(aq) How many milliliters of 3.00 M H2SO4(aq) are needed to react completly with 85.1g of BaO2(s)?

*November 22, 2010*

**Chemistry**

3.13g if CuNO3 is dissolved in water to make a 0.270 M solution. What is the volume of the solution?

*November 22, 2010*

**Chemistry**

Calculate the number of moles of solute in 18.33 mL of 0.1115 M K2Cr2O7(aq)

*November 22, 2010*

**chemistry**

How many grams of solute are present in 205 mL of .340 M KBr?

*November 22, 2010*

**Algebra**

Determine if the equation y = 2^x represents exponential growth or decay I thought at first it was growth but now I think it might be decay because there is no "b" in a parentheses so do I assume b is less than 1 so it's decay? Please help

*November 22, 2010*

**phyiscs**

A uniform plank of length 4.5 m and weight 233 N rests horizontally on two supports, with 1.1 m of the plank hanging over the right support (see the drawing). To what distance x can a person who weighs 454 N walk on the overhanging part of the plank before it just begins to tip?

*November 19, 2010*

**chemistry**

CO (g) + Cl2 (g) ↔ COCl2 (g In one experiment, 0.93 bar of CO was combined with 1.01 bars of Cl¬2 in a reaction vessel at 700K. After the system reached equilibrium, the total pressure was 1.24 bars. Calculate Kp0 for the system.

*November 17, 2010*

**physics help**

A 1.0 kg object is suspended from a vertical spring whose spring constant is 130 N/m. (a) Find the amount by which the spring is stretched from its unstrained length.

*November 15, 2010*

**science**

Are all materials in 3d why or why not?

*November 15, 2010*

**materials**

are all materials in 3d?

*November 15, 2010*

**physics help**

A 8.6 kg board is wedged into a corner and held by a spring at a 50.0° angle, as the drawing shows. The spring has a spring constant of 186 N/m and is parallel to the floor. Find the amount by which the spring is stretched from its unstrained length.

*November 15, 2010*

**Chem**

Can you please tell me if these are right? Classify the solutes in the following equations as a weak electrolyte, a strong electrolyte of a non electrolyte in water. a. XY2(s)=X2+(aq) +2Y-(aq) b. HX(g) ß=H+(aq) + X-(aq) c. XYZ(s)=XYZ(aq) d. YOH(s)=Y+(aq) + OH-(aq) a. ...

*November 14, 2010*

**integrals!!**

Compute the value of the integral using geometry. integral from -4 to 1 of (2x +8)dx

*November 8, 2010*

**calculus**

Referring to the Mean Value Theorem and Rolle's Theorem, how can I tell if f is continuous on the interval [a,b] and differentiable on (a,b).

*November 7, 2010*

**Chem**

Plese tell me if these are right. A 15.0-mL sample of NaCl solution has a mass of 15.78g. After the NaCl is evaporated to dryness, the dry salt residue has a mass of 3.26g. Calculate the following concentrations for the NaCl solution. a. %(m/m)= 3.26 x 100 / 15.78 = 20.7 b. %(...

*November 7, 2010*

**CHEM**

Will you please tell me if these are right? Write the symbol of the caton or anion that give(s) the following reaction:? 1. Forms a precipite with AgNO3 that does not dissolve in HNO3 2. Forms a gas with HCl 3. Give a bright, yellow-orange flame test 4. Forms a precipitate ...

*November 7, 2010*

**english**

Imagine you are on a local commission appointed to study the lack of proper recreation facilities for youth in your neighborhood. Decide what facilities should be recommended. Write an appropriate resolution to be presented to your county government. Remember to give the ...

*November 4, 2010*

**Physics**

Initially sliding with a speed of 2.3 m/s , a 1.8 kg block collides with a spring and compresses it 0.36 m before coming to rest. WHat is the force constant of the spring?

*November 3, 2010*

**physics please help**

A 5.00 kg ball (ball 1), moving to the right at a velocity of +4.00 m/s on a frictionless table, collides head-on with a stationary 7.60 kg ball (ball 2). Find the final velocities of the balls if the collision is as specified below. (a) elastic collision ball 1 ball 2 (b) ...

*November 2, 2010*

**help me physics**

suppose the cart has mass m = 203 g, and it strikes the clay at speed vo = 5.24 m/s and comes to a dead stop. Assume the track is frictionless, and the clay is crushed inward by 1.83 cm. a)Find the magnitude of the impulse exerted by the clay on the cart. 1 N-m i got this ...

*November 1, 2010*

**physics**

A 4111.0 kg truck is parked on a 14.6° slope. What is the friction force on the truck?

*October 26, 2010*

**physics**

A woman has a mass of 42.9 kg. What is her weight on earth? and what is her weight on the moon, where g=1.17 m/s2

*October 26, 2010*

**Calculus**

When air expands adiabatically (without gaining or losing heat), its pressure and volume are related by the equation where is a constant. Suppose that at a certain instant the volume is cubic centimeters and the pressure is kPa and is decreasing at a rate of kPa/minute. At ...

*October 26, 2010*

**Calculus**

When air expands adiabatically (without gaining or losing heat), its pressure P and volume V are related by the equation PV1.4=C where C is a constant. Suppose that at a certain instant the volume is 470 cubic centimeters and the pressure is 89 kPa and is decreasing at a rate ...

*October 26, 2010*

**Physical Science**

an airplane is flying at 600km/h at an altitude of 2.0km. When the sound of the airplane's engines seems to someone on the ground to be coming from directly overhead, how far away is she from being directly below the airplane?

*October 26, 2010*

**Chem**

Would you please tell me if these are right? A sample of helium has a volume of 325 ml and a pressure of 655 mm hg. What will be the pressure if the helium is compressed to 125 ml (t and n are constant) I got 1703 mm of Hg A 75.0 ml sample of oxygen has a pressure of 1.50 atm...

*October 23, 2010*

**Chem**

Please tell me if these are right. How many grams are needed to obtain 1.5 moles of magnesium oxide? I got 60grams is this right? Write a balanced equation for the reaction of the magnesium and the oxygen including their physical states. I got 2Mg=Mg2+O2? Thank You!

*October 23, 2010*

**english**

In the answer area below, write the conjunction in the following sentence. Sentence: Give it to the boy or his mother. This doesn't seem like it should be difficult, but I want to make sure I understand. Is 'or' the conjunction?

*October 22, 2010*

**Chemistry**

Can you tell me if these are right please? When 2.50g of copper reacts with oxygen the copper oxide product has a mass of 2.81g. What is the simplest formula of the copper oxide. I got Cu2O (copper (I) oxide). Aluminum and oxygen gas react to produce aluminum oxide. A.) write ...

*October 19, 2010*

**english**

In the answer area below, write the 2 adverbs in this sentence and explain how each adverb is used. Example: Eventually, she walked proudly. Answer: eventually - eventually tells when she walked ; proudly - proudly tells how she walked Sentence: She walked very slowly into the...

*October 19, 2010*

**english**

List the nouns in the following sentence. Next to each noun - label whether it is concrete or abstract by writing a "C" or an "A." Sentence: In the midst of the excitement, Samuel lost his pencil on the bus. This is what I believe to be correct: excitement-...

*October 19, 2010*

**Physics #2**

A car can decelerate at -3.40 m/s2 without skidding when coming to rest on a level road. What would be the magnitude of its deceleration if the road were inclined at 14° uphill? Assume the same static friction coefficient.

*October 11, 2010*

**Physics**

Suppose that you are standing on a train accelerating at 0.33g. What minimum coefficient of static friction must exist between your feet and the floor if you are not to slide?

*October 11, 2010*

**Physics**

Suppose that you are standing on a train accelerating at 0.33g. What minimum coefficient of static friction must exist between your feet and the floor if you are not to slide?

*October 11, 2010*

**algebra**

Two planes are 1,400 miles apart. They fly towards each other, one at 125 mph and the other at 175 mph. How long does it take the planes to pass each other (round to the nearest hundredth)?

*October 9, 2010*

**physics**

A cheetah is hunting. Its prey runs for 3.21 s at a constant velocity of +8.36 m/s. Starting from rest, what constant acceleration must the cheetah maintain in order to run the same distance as its prey runs in the same time?

*October 8, 2010*

**physicS**

so thatd be H=dSin17.2 40.45m=dsin17.2 d=40.45/sin17.2 d=136.8 it all looks right, but for some reason incorrect, if anyone has a chance, can you check my math for me? i cant understand where i went wrong

*October 8, 2010*

**physicS**

A skier is gliding along at 6.93 m/s on horizontal, frictionless snow. He suddenly starts down a 17.2° incline. His speed at the bottom is 29.7 m/s. What is the length of the incline? i understand that the equation used is gH= change in (v^2)/2 so i plug in 9.8H=(29.7^2-6....

*October 8, 2010*

**college statistics**

In Chapter 5, Exercise 9, we studied the variability of crime rates and police expenditures in the eastern and Midwestern United States. We’ve now been asked to investigate the hypothesis that the number of crimes is related to police expenditures per capita because ...

*October 6, 2010*

**Projectile Motion Physics**

An Arrow directed at a stationary target is shot at an angle of E25N. The arrow hits the intended target at the same height from which it is launched, 3.0s later. Determine the distance from the archer to the target.

*October 6, 2010*

**1st grade**

fine the rule

*September 27, 2010*

**math**

find the decimal notation for 63/3/8

*September 25, 2010*

**physics**

An athlete executing a long jumper leaves the ground at a 27.0 degree angle and travels 7.89 m. What was the takeoff speed? If this speed were increased by just 5.0%, how much longer would the jump be? I came up with a take off speed of 27.4 but the system is saying that is ...

*September 22, 2010*

**math**

nvm you don't have to answer this. i was told the wrong problem.

*September 20, 2010*

**math**

my friend asked me how to do this probelm and i could not figure it out for the live of me. its simple im pretty sure. (6-5i)/(6+5i) I tried using the conjugate method and my answer did not come out correct. can you please answer this?

*September 20, 2010*

**Chemistry**

A 0.25g sample of a pretzel is burned. The heat it gives of is used to heat 50.g of water from 18 to 42 degrees C. what is the caloric value of the pretzel in kcal/g? Can someone walk me through step by step?

*September 18, 2010*

**Chemistry**

175g of water was heated fro 15 to 88 degrees C. how many kilocalories were absorbed by the water? I got 94.5 kcal. Is this right?

*September 18, 2010*

**Chemistry. can jus anyone giv me ther opinion.**

k thank u

*September 17, 2010*

**Chemistry. can jus anyone giv me ther opinion.**

idk this is the question to a quiz im taking i askd my teacher and he didn't even kno what to say i think its D and i jus need to get this question rite and ill pass but if i miss it then i fail. i jus want as much help as i can get.

*September 17, 2010*

**Chemistry. can jus anyone giv me ther opinion.**

Eva has two containers labeled A and B. The diameter of container A is 8 inches and the diameter of container B is 12 inches. If Eva pours the water from container A into container B, which will occur...

*September 17, 2010*

**English**

its talking about not quite understanding maturity in which a young person grows up to become an adult. for some its like watking through a doorway and for others it seems they can't even get the door open.

*September 17, 2010*

**Chemistry...HELP!!!!**

In a reaction in which A + B yields AB, the reaction is referred to as a _________. A. decomposition reaction B. double-replacement reaction C. combustion reaction D. composition reaction i think is a

*September 17, 2010*

**Chemistry**

In a reaction in which A + B yields AB, the reaction is referred to as a _________. A. decomposition reaction B. double-replacement reaction C. combustion reaction D. composition reaction

*September 17, 2010*

**Economics**

Why has China begun an economic shift towards a free enterprise system?

*September 16, 2010*

**High school economics**

thanks!

*September 16, 2010*

**High school economics**

Where might you take someone from China or Cuba to show them the differences between the economy in the US and their country?

*September 16, 2010*

**Chemistry, Solutions**

Two or more combined substances that do not react form a _________. solution mixture substance compound

*September 16, 2010*

**Chemistry**

What types of elements are involved in metallic bonding? A. noble gases B. metals and non-metals C. non-metals only D. metals only

*September 16, 2010*

**Chemistry**

Acids and bases react with one another to form compounds called ______? A. salts B. ions C. mixtures D. salts, ions, and mixtures

*September 16, 2010*

**Math - polynomial function**

Write a polynomial function with integral coefficients having the given roots. 1.) 0, -1/2, 6 2.) +or- 5i

*September 12, 2010*

**College Algebra**

suppose that the area of a square is six times its perimeter. find the length of a side of the square

*September 12, 2010*

**Science**

What is the specific heat of an unknown substance if 2000 J of energy are required to raise the temperature of 4 grams of the substance 5 degrees Celsius?

*September 10, 2010*

**chemistry**

how to balance ZnO+2HCl yields ZnCl2+H2O

*September 8, 2010*

**math**

Hoshi walk 10 meters in 3 sec. a. what is her walking rate? b. at this rate how long does it take to walk 100 meters c. suppose she walks the same rate for 50 sec. how far does she walk d. wright an equation that represents the distance D that Hoshi walks in 1 sec

*September 2, 2010*

**math**

easy

*September 1, 2010*

**The Question that was not answered. (twice)**

What are the four basic levels of ecological study, and what is the focus of inquiry at each of these levels? I don't know what it's asking to start with and can't find anything relevant online, in my textbook or in my study guide! Since it says levels, I think it ...

*August 28, 2010*

**bio**

What are the four basic levels of ecological study, and what is the focus of inquiry at each of these levels? I don't know what it's asking to start with and can't find anything relevant online, in my textbook or in my study guide! Since it says levels, I think it ...

*August 28, 2010*

**Chemistry**

sources of error can include human errors made by you during the experimentation or your surroundings which may have affected your outcome.

*August 28, 2010*

**AP Biology**

What are the four basic levels of ecological study, and what is the focus of inquiry at each of these levels? I don't know what it's asking to start with and can't find anything relevant online, in my textbook or in my study guide! Since it says levels, I think it ...

*August 28, 2010*

**Math**

haha sorry. i didn't bother to read the entire thing. you must divide first in order to root both sides

*August 28, 2010*

**Math**

Please excuse my dear aunt sally

*August 28, 2010*

**Math**

Show that the transformation T:R^2->R^2 given T(x1,x2)=(3x1-5x2,x1+2x2) is linear by verifying that satisfies the definition of linear.

*August 13, 2010*

**Linear Alebra**

Show that the transformation T:R^2->R^2 given T(x1,x2)=(3x1-5x2,x1+2x2) is linear by verifying that satisfies the definition of linear.

*August 13, 2010*

**Algebra**

For what real number k does 3x^2 k factor as 3(x 2)(x + 2)? Can someone please help with this question? I can not understand how it says to solve this in the book

*August 5, 2010*

**British Literature**

what is number 4?

*July 21, 2010*

**MATH HELP**

any points: I can use (2,6) or (10,70)?

*July 20, 2010*

**MATH HELP**

1. Consider the following. f(x)=8x-10 g(x)=x^2-4x+10 (a) Find the points of intersection of the graphs. ANSWER:(2,6) are the smaller values and (10,70) are the larder values (b) Compute the area of the region below the graph of f and above the graph or g. How do I answer part b?

*July 20, 2010*

**programming**

I am in a beginners class in computer programming and we have been designing our programs in pseudocode format and this is a homework question I have to solve this is how the question is written on my paper...can you please help, Thanks. Homework question: A car's miles-...

*July 10, 2010*

**programming**

I am in a beginners class in computer programming and we have been designing our programs in pseudocode format and this is a homework question I have to solve this is how the question is written on my paper...can you please help, Thanks. Homework question: A car's miles-...

*July 10, 2010*

**programming**

I am in a beginners class in computer programming and we have been designing our programs in pseudocode format and this is a homework question I have to solve this is how the question is written on my paper...can you please help, Thanks. Homework question: A car's miles-...

*July 10, 2010*

**chem**

A sample of gas confined in a cylinder with a movable piston is kept at constant pressure. The volume of the gas doubles when the temperature of the gas is changed from

*July 10, 2010*

**MATH**

Evaluate the indefinite integral. (Use theta for ƒÆ.) ç(8ƒÆ + cos(7ƒÆ))dƒÆ Ans: blank + C C is constant. How do I evaluate it?

*July 1, 2010*

**Math**

Find the general antiderivative of f (x) and check your answer by differentiating. f(x) = x^5 + 9 Need Help.

*July 1, 2010*

**Math**

Use the following table of values to estimate the area under the graph of f(x) over [0, 1] by computing the average of R5 and L5. Table: x: 0 0.2 0.4 0.6 0.8 1 f(x): 51 48 46 43 41 38 I need help with this problem.

*July 1, 2010*

**alg**

The answer would be D. 1. (2/x-1)-3/4= (5/x-1) -(2/x-1) -(2/x-1) 2. -3/4=(3/x-1) 3. (x-1)-3/4= 3 (distribute and you'll get #4.) 4. -3/4x+3/4=3 5.-3/4x= 3-3/4 6. -3/4x= 2.25 7. 2.25/(-3/4) x= -3

*July 1, 2010*

**physics**

a ring rotates ar 30rad/s and has a radius of 3m and a mass 0f 100kg. If a disk(mass=40kg and with a radius of 4m) is dropped on the ring so the centers are aligned, what will be the resulting rotational speed of the ring-disc combination?

*June 29, 2010*

**Statistics**

87.65

*June 24, 2010*

**Calculus**

at the end when you get dy/dx = 20/(5x+4y -16) ... what do you replace y with? in the beginning you have y = 4ln(5x+4y) the answer is only in terms of x...

*June 19, 2010*

**Calculus**

If f(x) = 4ln(5 x+ 4ln(x)), find f'( x ).

*June 19, 2010*

**statistics**

Evolutionary theories often emphasize that humans have adapted to their physical environment. One such theory hypothesizes that people should spontaneously follow a 24-hour cycle of sleeping and waking-even if they are not exposed to the usual pattern of sunlight. To test this...

*May 29, 2010*

**math**

500 acres of land costs 800 dollars and every year there is a three percent increase in price then it gives the end cost was one thousand. it asks for the equation using v=p(1+r) raised to the n power

*May 25, 2010*

**math**

A certain number changes from 200 to 900 within three hours find the vaulue of k using the formula n times e raised to k times t

*May 25, 2010*

**Physics**

that isn't right either but i guess this thing is retarded so w.e thx though

*May 8, 2010*

**Physics**

A heat engine has the three step cycle shown above. Starting from point A, 1 L (liter) of ideal gas expands in the isobaric (constant pressure) process A to B at P = 2 atm. B to C is isovolumetric process at V = 5 L, and C to A is an isothermal (constant temperature) ...

*May 8, 2010*

**Physics difficult... chris help again plz.**

A heat engine has the three step cycle shown above. Starting from point A, 1 L (liter) of ideal gas expands in the isobaric (constant pressure) process A to B at P = 2 atm. B to C is isovolumetric process at V = 5 L, and C to A is an isothermal (constant temperature) ...

*May 8, 2010*

**Physics**

this isn't the right answer either

*May 7, 2010*

**Physics**

A heat engine has the three step cycle shown above. Starting from point A, 1 L (liter) of ideal gas expands in the isobaric (constant pressure) process A to B at P = 2 atm. B to C is isovolumetric process at V = 5 L, and C to A is an isothermal (constant temperature) ...

*May 7, 2010*

**science**

Scientists performed an experiment to determine whether there is a connection between learning ability and food. They took two groups of 20 mice each, all from the same purebred strain. The mice were deprived of food for 3 days and then given a standard learning session in ...

*April 28, 2010*

**physics**

A physics student sits by the open window on a train moving at 25 m/sec towards the east. Her boyfriend is standing on the station platform, sadly watching her leave. When the train is 150 meters form the station, it emits a whistle at a frequency of 3000 Hz. What is the ...

*April 21, 2010*