Wednesday

March 4, 2015

March 4, 2015

Total # Posts: 1,691

**Chemistry**

which molar mass do you use? pb(OH)2 or pb2+?
*April 1, 2013*

**Physics**

Question 2. 3 Consider a box that explodes into two pieces while moving with Fig. 9-24 a constant positive velocity along an x axis. If one piece, with mass : m1, ends up with positive velocity v1, then the second piece, with : mass m2, could end up with (a) a positive ...
*April 1, 2013*

**Science Physics**

So weight is mass times gravity On earth, w(12N) = m*10m/s2. Solve for mass. Mass= 1.2N Use that to find mars' gravity. 4.8= (1.2)*g Solve for g. G= 4m/s2
*April 1, 2013*

**Math**

1mile * $2.25= $2.25 Remaining miles are 4.2 which is 42 tenths of miles. 42*.15= $6.30 Total for ride is 6.30 + 2.25= $8.55 He paid $10, so 10-8.55=$ 1.45 which is the change or can be called the tip. 2trillion = 2,000,000,000,000 750 billion= 750,000,000,000 Subtract 2,000,...
*April 1, 2013*

**Math: Finding m<A**

ABC~DEF m<B = 25', m<D = 45', m<E = 25' How do find m<A?
*March 29, 2013*

**Geoometry Help: Find EF**

Thank you so much. Saved me from a big mistake :)
*March 29, 2013*

**Geoometry Help: Find EF**

ABC~DEF AB = 36, BC = 24, DE = 48 m<B = 110', m<E = 110' EF = ? I think it's 68. Yes? Or is something else?
*March 29, 2013*

**chemistry**

What will be the fastest reaction if a strong base, such as sodamide, reacts with a secondary alcohol, such as (2S)-butanol? a) deprotonation of the alcohol b) substitution with racemization of stereochemistry c) elimination to form the more substituted alkene d) substitution ...
*March 29, 2013*

**achieving academic execellence**

Becoming a discerning consumer of research is something you can achieve be practicing good research skills and using your A. critical thinking B. education C. resources D. college library
*March 26, 2013*

**chemistry**

provide the appropriate IUPAC name for the following alcohol. designate e or z 8 carbon chain double bonds between 4 and 5 and 6 and 7 methyl group on 6 OH on the second carbon [the only hint i got from this homework is to begin my answer with octadien-2-ol. can someone help ...
*March 25, 2013*

**chemistry quick question**

i just realized after entering my question my structure did not stay the way I wanted it to. the CH2 and OH are supposed to be over the 4th carbon in the chain and the CH3 is supposed to be under the 3rd.
*March 25, 2013*

**chemistry quick question**

I need help with something and can't find this anywhere online. my structure looks like this OH CH2 CH3CH2CH2CHCHCH2CH3 CH3 So that OH looks like it is on a ethyl group. I need to write the IUPAC name and I wrote 3-methyl-4-heptanol but realized my mistake as that would ...
*March 25, 2013*

**organic chemistry**

thank you for helping me, but since this question totally confuses me how did you get to this answer?
*March 21, 2013*

**organic chemistry**

can anyone help me please?
*March 21, 2013*

**organic chemistry**

which of the following represents the best strategy for synthesizing 2-butanol, CH3CH2CH(OH)CH3 a) CH3CH=CHCH3 + [H30]+ b) CH3CH2C (triple bond) CH + [H3O]+ c) CH3CH=CH2+ [CH3OH2]+ d) CH3C (triple bond)CCH3 + [H3O]+
*March 21, 2013*

**Speed'Distance'Time**

Determine the time taken when, distance is 7150 km and speed is 780 km/hr.
*March 19, 2013*

**Speed'Distance'Time**

Find out the distance covered when, speed is 960 km/hour and time is 1 hour 50 minutes.
*March 19, 2013*

**Physics**

A 500 kg elevator starts from rest. It moves upward for 4.00 s with constant acceleration until it reaches its cruising speed, 1.75 m/s. (a) What is the average power of the elevator motor during this period? (b) How does this power compare with the motor power when the ...
*March 16, 2013*

**Physics**

Sewage at a certain pumping station is raised vertically by 5.57 m at the rate of 1 860 000 liters each day. The sewage, of density 1 050 kg/m3, enters and leaves the pump at atmospheric pressure and through pipes of equal diameter. (a) Find the output mechanical power of the ...
*March 16, 2013*

**math**

Earth's mass, in kilograms, is 5.97x10^24. the moon's mass is 7.34x10^22. How many times greater is Earth's mass (in scientific notation)?
*March 14, 2013*

**Math **

A backpacking team is hiking At an average speed of 2 1/2 miles per hour. At that rate, how long will it take for a hike of 8 3/4 mi?
*March 8, 2013*

**Math**

55 1/2
*March 8, 2013*

**Math**

Karina earned $60 from her part time job. She spent 3/10 of it on food and 1/4 of it on music. How much money does she have left?
*March 8, 2013*

**Math**

A DVD case is 9/16 in. Thick. How many of these cases will fit on a shelf that is 1 1/2 ft wide
*March 8, 2013*

**Math**

A DVD case is 9/16 in. Thick. How many of these cases will fit on a shelf that is 1 1/2 ft wide?
*March 8, 2013*

**Math**

A new section of freeway will be 8 1/2 mi long. During the first month of construction, 2 7/10 mi were built. During the second month, 3 3/5 mi were built. How many more miles were left to build?
*March 8, 2013*

**Math**

2 1/5
*March 8, 2013*

**Math**

6 2/5
*March 8, 2013*

**Math**

Mr.Quakers science class has a 16 gallon aquarium that is 3/5 full. How much water is needed to fill it?
*March 8, 2013*

**Business Statistics**

1. Suppose that the mean of the annual return for common stocks from 1950 to 2012 was 9.4%, and the standard deviation of the annual return was 17.5%. Suppose also that during the same 62-year time span, the mean of the annual return for long-term government bonds ...
*March 6, 2013*

**Chemistry**

Ammonia is used as a fertilizer throughout the world. It is often produced by reacting nitrogen gas with hydrogen gas in a synthesis reaction. How much ammonia in grams can be produced from 9207 grams of nitrogen and 44 000 L of hydrogen?
*March 4, 2013*

**Chemistry**

Answer had to be expressed as just as an isotope so it is **108/48Cd DrBob222 Can you explain how you got the 48 though? Where did the other proton come in when you just added to the mass?
*March 1, 2013*

**Chemistry**

I was thinking of something like this? (I'm not sure how to approach this problem): 108/47Ag ---> 107/47Ag + 1/0n then, 108/46Pd ---> 108/47Ag + 0/-1e
*March 1, 2013*

**Chemistry**

When silver-107 is bombarded with a neutron, a different isotope of silver forms and then undergoes beta decay. What is the final product? (My Hints: Write two separate nuclear equations.)
*March 1, 2013*

**Chemistry**

**241/95Am ----> 237/93Np + 4/2He Is the correct answer indeed. I was confused about the part where it was just talking about subatomic particles and thought I wasn't adding an element to balance the equation but neutrons. Thank you!
*March 1, 2013*

**Chemistry**

There are several technological applications for the transuranium elements (Z > 92). An important one is in smoke detectors, which can use the decay of a tiny amount of americium-241 to neptunium-237.What subatomic particle is emitted from that decay process? Write a ...
*March 1, 2013*

**Chemistry**

75.7 days
*March 1, 2013*

**Chemistry**

Radium-223 has a half-life of 11.4 days.Approximately how long would it take for the activity of a sample of Radium-223 to decrease to 1.00% of its initial value?
*March 1, 2013*

**Pre-Calculus**

The stopping distance D of a car after the brakes have been applied varies directly as the square of the speed s. A certain car traveling at 70 mi/h can stop in 343 ft. What is the maximum speed it can be traveling if it needs to stop in 160 ft?
*February 26, 2013*

**college physics**

You are in the lab with a 10 V battery. You have a 10 W light bulb and you want to put 0.75 A of current through the light bulb and 7.5 V across the light bulb. This will allow the light bulb to have a brightness proportional to 5.625 W. Assuming any resistors that you need, ...
*February 26, 2013*

**Math**

Denna bought a bag of jelly beans. 1/3 are pink and 1/6 are blue. The rest are green. How many are green?
*February 25, 2013*

**Physics**

A thundercloud has an electric charge of 43.2 C near the top of the cloud and -38.7 C near the bottom of the cloud. The magnitude of the electric force between these two charges is 3.95 x 106 N. What is the average separation between these charges? (kc = 8.99 ×109 N &#...
*February 20, 2013*

**math**

gfrtyyngjtfghdyhjhv ndfhd,bbgrtf
*February 18, 2013*

**Math**

If the product of four tenths and six tenths is subtracted from the sum of four tenths and six tenths, what is the difference?
*January 30, 2013*

**math 121 **

jennifer is asked to complete 5 of the 7 essay questions on her literature exam how many choices does jennifer have?
*January 28, 2013*

**Engineering Math**

sorry didn't mean to lol but it is lol
*January 28, 2013*

**Engineering Math**

lol
*January 28, 2013*

**physics**

Suppose a 28.5 kg object is moving at 38.4 m/s along the x-axis just before it strikes a stationary 13.0 kg object. After the collision, the 28.5 kg object is moving with a velocity of 20.0 m/s at an angle of 5.79 degrees relative to the x-axis. What is the magnitude of the ...
*January 25, 2013*

**Chemistry**

What is the density, in grams per liter, of N subscript 2 gas at STP
*January 24, 2013*

**General math **

7t-6=104
*January 24, 2013*

**mt450**

need to focus on the main critical elements of simulation
*January 22, 2013*

**mt450**

Now that you have turned in your Simulation Final Project paper, the next step is to turn in your PowerPoint presentation of it. In the workplace, presentations like this play a key part in conveying marketing plans. Presentation requirements: • A minimum of 8 slides and ...
*January 22, 2013*

**Algebra**

Thanks. I figuired out the working, but not sure how to use the Let statement. Would it be correct to say Let A = original scholarship amount A = 1-1/3 -1/4-1/4 x72,000 A = 1/6 x 72 = 432,000
*January 10, 2013*

**Algebra**

Mary, Margaret, Ron and Nick are to share a sholarship. Ron receives 1/3 of the scholarship; Nick gets 1/4 of the scholarship; Mary receives the same as Nick, and Margaret receives $72,000. Find each person's share in the scholarship as well as the original scholarship ...
*January 10, 2013*

**literature**

In "Life without Principle," Thoreau writes, "If my wants should be much increased, the labor required to supply them would become a drudgery." What does this statement mean?
*December 12, 2012*

**Chemistry**

If 355 g Al(NO3)3 reacts with an excess of K2CrO4, how many moles of KNO3 would be produced?
*December 12, 2012*

**chemistry**

3.50 mol Al(NO3)3 reacts with 5.00 mols K2CrO4, the total number of moles of Al2(CrO4)3 and KNO3 would be? Here is the equation if it's needed. 2 Al(NO3)3(aq) + 3 K2CrO4(aq) → Al2(CrO4)3(s) + 6 KNO3(aq)
*December 12, 2012*

**Chemistry**

How many atoms of O are in 4 moles of (NH4)3PO4 - 6H2O? The answer is 2.41x10^25 I have no clue how to arrive at this answer.
*December 11, 2012*

**Mathematics of Retailing**

An owner of a laundry shop received an invoice for purchasing 200 bottles of liquid detergent at RM15 each, and 300 bottles of fabric softener at RM8 each. The invoice dated on 6th August 2010. He was offered trade discount 10% and 8%, with cash discount 10/10, 5/20, n/30. The...
*December 9, 2012*

**physics! please help!! **

A particle rotates counterclockwise in a circle of radius 6.5 m with a constant angular speed of 7.4 rad/s. At t = 0, the particle has an x coordinate of 3.3 m and y > 0 . A) Determine the x coordinate of the particle at t = 0.716 s. Answer in units of m ( I know this ...
*December 6, 2012*

**physics**

A particle rotates counterclockwise in a circle of radius 6.5 m with a constant angular speed of 7.4 rad/s. At t = 0, the particle has an x coordinate of 3.3 m and y > 0 . A) Determine the x coordinate of the particle at t = 0.716 s. Answer in units of m ( I know this ...
*December 6, 2012*

**physics help please!**

thank you!!!!! i must have messed up on my calculations
*December 6, 2012*

**physics help please!**

The motion of a piston in an auto engine is simple harmonic. The piston travels back and forth over a distance of 23 cm, and the piston has a mass of 1.7 kg. 2515 rpm 23 cm max speed of the piston 30.28757 m/s What is the maximum force acting on the piston when the engine is ...
*December 6, 2012*

**statistics**

Scores from a statistics exam are reported as deviation scores. Which of the following deviation scores indicates a higher position in the class distribution?
*December 6, 2012*

**physics**

A 28.6-g bullet is fired from a rifle. It takes 2.36 × 10-3 s for the bullet to travel the length of the barrel, and it exits the barrel with a speed of 710 m/s. Assuming that the acceleration of the bullet is constant, find the average net force exerted on the bullet.
*December 5, 2012*

**chemistry**

just a guess but would all but C be stable?
*December 4, 2012*

**chemistry**

A magic number is the name given to certain numbers of protons or neutrons that have a high correlation to stability in nuclei. Magic # of protons: 2,8,20,28,50,82 Magic # of neutrons: 2,8,20,38,50,82,126, 184 Using general trends, predict the stability of the following nuclei...
*December 4, 2012*

**calculus**

1. (30 points) Consider a manufacturer whose total cost of producing x items is given by c(x)=10000+5x+1/9x^2. a. What is the average cost function A(x)= c(x)/x? b. How many items should the manufacturer produce in order to minimize average cost? c. What is the smallest ...
*December 3, 2012*

**physics**

An object is projected upward from the surface of the earth with an initial speed of 2 km/s. The acceleration of gravity is 9.81 m/s^2. Find the maximum height it reaches. Answer in units of km.
*November 30, 2012*

**Math**

A rectangle area spans . The length must be 20ft more than the width. What are the dimensions?
*November 30, 2012*

**physics**

Wow thank you so much! This problem has been bothering me for a week now
*November 30, 2012*

**physics**

A hydraulic brake system is shown. The area of the piston in the master cylinder is 6.32 cm^2, and the area of the piston in the brake cylinder is 1.83 cm^2. The coeﬃcient of kinetic friction between the brake shoe and the wheel drum is 0.443. How large is the ...
*November 30, 2012*

**Math**

When rolling two dice, what is the probability that the sum is 7 given that one die is a 5?
*November 29, 2012*

**college physics**

A hydraulic brake system is shown. The area of the piston in the master cylinder is 6.32 cm^2, and the area of the piston in the brake cylinder is 1.83 cm^2. The coeﬃcient of kinetic friction between the brake shoe and the wheel drum is 0.443. How large is the ...
*November 29, 2012*

**chem**

pH= -log [H+] pH < 7 is acidic and pH > 7 is basic. for example pH= - log [1.0e-11M] pH= 11 therefore basic solution.
*November 29, 2012*

**physics**

this is a huge help! thanks again!
*November 29, 2012*

**physics**

Wow thank you. I was really lost.
*November 29, 2012*

**math**

you deposit $2200 in an account that pays 3% interest, after 15 years you withdraw, what is the balance if the interest is compounded continuously
*November 29, 2012*

**physics**

A liquid of density 1354 kg/m^3 ﬂows with speed 2.45 m/s into a pipe of diameter 0.29 m. The diameter of the pipe decreases to 0.05 m at its exit end. The exit end of the pipe is 7.82 m lower than the entrance of the pipe, and the pressure at the exit of the pipe is 1.4...
*November 29, 2012*

**Chemistry**

how do I convert moles of Cr2O3 to moles of H2CrO4? I don't understand what this means
*November 27, 2012*

**Chemistry**

3C3H8 + 20H2CrO4-> 9CO2 + 10Cr2O3 + 32H2O Suppose you want to make 1.50 g of chromium (III) oxide, how many ml of 6.25M chromic acid will you need to use if the percent yield of the reaction is 68.6%?
*November 27, 2012*

**Phoenix**

Why do you think Windows is so prevalent? What do the other systems have to offer that Windows does not? Who uses the other systems?
*November 27, 2012*

**Financial management**

what is the principle investment ? you have $1728.34 compounded daily at 3.4% and its invested for 9 years
*November 27, 2012*

**math**

for the equations y=5x+50 and y=6x+25, for how many hats will the cost be the same and what is that cost?
*November 26, 2012*

**Chemistry**

Sodium vapor lamps, use for public lighting, emits 489 nm yellow light. What energy is emitted by: a) an excited sodium atom when it generates a photon? b) 1 mole of excited sodium atoms at this wavelength?
*November 25, 2012*

**Chemistry**

This helped me with the amount in grams of Cr2O3, but what do I do with the 2nd part, the 35.0 ml of 6.26M chromic acid?
*November 23, 2012*

**Chemistry**

3C3H8 + 20H2CrO4-->9CO2 + 10 Cr2O3 + 32H2O What mass of chromium (III) oxide will be formed by complete reaction of 1.50g of propane with 35.0ml of 6.26M chromic acid?
*November 23, 2012*

**Chemistry**

a stock solution of perchloric acid is 75.5% perchloric acid and has a density of 1.67g/ml. What is the molarity of the solution?
*November 23, 2012*

**math**

How high is a wall that casts a 15ft shadow at the same time that a 4ft flag pole casts a 4ft shadow?
*November 23, 2012*

**college english**

what is a good attention getter sentence on carpal tunnel syndrome?
*November 21, 2012*

**statistics**

The reaction time of subjects to a certain psychological experiment is considered to be normally distributed with a mean of 20 seconds and a standard deviation of 4 seconds. What is the reaction time such that only 10% of subjects are faster?
*November 21, 2012*

**statistics**

The reaction time of subjects to a certain psychological experiment is considered to be normally distributed with a mean of 20 seconds and a standard deviation of 4 seconds. What is the reaction time such that only 10% of subjects are faster?
*November 21, 2012*

**statistics**

Entry to a certain University is determined by a national test. The scores on this test are normally distributed with a mean of 500 and a standard deviation of 100. Tom wants to be admitted to this university and he knows that he must score better than 70% of the students who ...
*November 20, 2012*

**Physics**

A roller coaster is initially at a height of 40 m above the ground and has an initial velocity of 15 m/s. Using conservation of energy, find the velocity of the roller coaster at a height of 5 m above the ground.
*November 19, 2012*

**Chemistry**

What mass of Uranium (in mg) is contained in 1ml of 4.55M (UO2)3(PO4)3 solution? How do I solve this? *all numbers are subscripts
*November 18, 2012*

**physics what am i doing wrong?**

I figured it out......i dont understand why no one has helped me yet in the past week
*November 16, 2012*

**physics what am i doing wrong?**

Three masses are arranged in the (x, y) plane. 3kg (0,0) 7kg (10,0) 6kg (0,3) What is the magnitude of the resulting force on the 3 kg mass at the origin? The value of the universal gravitational constant is 6.6726 × 10^−11 N · m^2/kg^2. Answer in units of N...
*November 16, 2012*

**can someone please help w/ physics?**

anybody? please?
*November 16, 2012*

**can someone please help w/ physics?**

An object of mass 154 kg moves in a smooth straight tunnel of length 2990 km dug through a chord of a planet of mass 3.19 × 10^24 kg and radius 1 × 10^7 m Find the eﬀective force constant of the harmonic motion. The value of the universal gravitational ...
*November 16, 2012*

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