# Posts by alex

Total # Posts: 3,757

**Chem**

The following substances undergo complete combustion in a bomb calorimeter. The calorimeter assembly has a heat capacity of 5.136 ^ C. In each case, what is the final temperature if the initial water temperature is 22.37^ C? 0.3268g caffeine, C8H10N4 (heat of combustion = -...

**College Chemistry**

Calculate the heat in joules needed to warm 225g of water from 88.0 degrees Celsius to its boiling point 100.0 degrees Celsius

**Biology**

1)Animal cells prefer to be in isotonic solution, while plant cells prefer to be in hypotonic solution. Explain what this means and why it is so. 2.) In terms of Gibbs free energy, what does “unstable” mean? Also, give at least two additional ways to say that a ...

**physics**

A box slides down a plane 8 m long that is inclined at an angle of 30 degrees with the horizontal. If the box starts from rest and u = 0.25, find a.) the acceleration of the box, b.) it's velocity at the bottom of the plane, and c.) the time required for it to reach the ...

**Math**

Sare estimated 32x45 by using 30x40. How could Sara make a more accurate estimate?

**Calculus 1**

Find the derivative of y with respect to x. y=(x^6/6)(lnx)-(x^6/36) So far this is what I've gotten: y=(x^6/6)(lnx)-(x^6/36) y=(1/6)x^6(lnx)-(1/36)x^6 y'=(1/6)x^5(1/x)+lnx(x^5)-(1/6)x^5 What do I do now?

**CHEMISTRY**

Explain Why The Addition Of An Electron To A Chlorine Atom Is An Exothermic Process And The Addition Of An Electron To A Magnesium Atom Is An Endothermic Processs

**math**

what is the prime factorization of 1 bilion using exponents?

**Physics**

Can you tell me the answer for c and d. I got the one for a and b correct but c says it's not correct. I put 21.96N.

**Physics**

A 2.42kg block starts from rest at the top of a 22.9◦ incline and accelerates uniformly down the incline,moving 2.41m in 2.14s. The acceleration of gravity is 9.81m/s2. a) What is the magnitude of the acceleration of the block? Answer in units of m/s2 b) What is the coe...

**English**

?

**Chemistry**

Then if it Decrease the system will shift to the side with more moles of gas?

**Chemistry**

I have a question about this one 2N2O(g) ⇋ O2(g) + 2N2(g), what happens to the equilibrium position if the pressure decreases? Is going to shift to the right or to the left???

**Geography**

5 countries in Africa with coastlines on the Atlantic Ocean and lie between 20 degrees n and 10 degrees n? I think they are guinea,guinea-Bissau,Gambia,Senegal and Mauritania. Is this right?

**statistics**

Given the length an athlete throws a hammer is a normal random variable with mean 50 feet and standard deviation 5 feet, what is the probability he throws it between 50 feet and 60 feet?

**Physics (Difficult)**

A uniform rectangular bar with cross-section 66 mm x 54 mm and of length 1.7 m has mass 16kg. It pivots about an axis prependicular to the wider face. The axis is equidistant from the edges and 170 mm from one end. What is the relevant second moment of mass?

**physics**

A 0.395-kg blue bead slides on a frictionless, curved wire, starting from rest at point in the figure below, where h = 1.50 m. At point , the blue bead collides elastically with a 0.650-kg green bead at rest. Find the maximum height the green bead rises as it moves up the wire.

**physics**

a .77 kg book with dimensions of 28.9 cm by 20.2 cm is on a table. What force does the book apply on the table?

**geography**

Is mexico the large north american country that the tropic of cancer cuts through?

**math 7**

the weight of thewater in a full bathtub in a quarter ton. How many pounds is a quarter ton/

**Physics**

A crank of length 190mm is initially at 65 degree above the horizontal, and rotates through 35 degree towards the horizontal. A vertically downward force of 160 N acts on the outer end of the crank. Calculate the work done by the force.

**Physics**

A car travels in a flat circle of radius R. At a certain instant the velocity of the car is 24 m/s west,and the acceleration of the car has componets of 2.4 m/s^2 east and 1.8m/s^2 south. Find the total displacement of the object (from t=0 to 25)

**College Chemistry**

We will calculate the amount of acid to use in each titration. Assume that you are using 0.0512 M NaOH(aq). A good volume of NaOH(aq) to use per titration is 15mL. From this molarity and volume, the moles of NaOH can be calculated. Since the unknown acid is monoprotic, this ...

**Algebra**

He isn't supposed to give you the answers. You should be greatful he helped you find them.

**physics**

help! Two charges A and B are fixed in place, at different distances from a certain spot. At this spot the potentials due to the two charges are equal. Charge A is 0.22 m from the spot, while charge B is 0.54 m from it. Find the ratio qB/qA of the charges.

**physics**

trying to study but stuck with this one. Two tiny spheres have the same mass and carry charges of the same magnitude. The mass of each sphere is 4.62 x 10-6 kg. The gravitational force that each sphere exerts on the other is balanced by the electric force. Determine the charge...

**Physics**

Two cars pass each other traveling at the same speed. One car has a constant velocity of 18.0 m/s east. The other car has a constant acceleration of 3.00 m/s^2, west. How much time will have elapsed until the cars are 128 m apart?

**geography**

Is this correct? The Caribbean Sea is the second largest sea in the world that is south of cuba.

**Math**

Find the limit of (2cosx+3cosx-2)/(2cosx-1)as x tends to pi/3.

**phy**

Integral of F(x) = .5mv^2 18x-.5(.53)x^2=.5mv^2 find v.

**Chemistry**

If the Kb of a weak base is 2.6 × 10-6, what is the pH of a 0.24 M solution of this base?

**Chemistry**

extremely easy. Sorry! pH=1 and pOH = 13

**Chemistry**

Calculate the pH and the pOH of an aqueous solution that is 0.025 M in HCl(aq) and 0.075 M in HBr(aq) at 25°C.

**calculus**

Prove (by using a point and a normal vector) that the plane whose intercepts with the coordinate axes are x=1, y=1, and z=1 is given by the equation x+y+z=1

**Algebra**

i don't know how to do it

**chemistry**

5850.18

**physics**

Please help! Two charges are placed on the x axis. One of the charges (q1 = +8.71C) is at x1 = +3.00 cm and the other (q2 = -28.6C) is at x2 = +9.00 cm. Find the net electric field (magnitude and direction given as a plus or minus sign) at (a) x = 0 cm and (b) x = +6.00 cm.

**chemisry**

compare and contrast the abilities of carbon, sodium, and neon to form chemical bonds?????

**physics**

need help with this problem A charge of -2.73 uC is fixed in place. From a horizontal distance of 0.0465 m, a particle of mass 9.50 x 10-3 kg and charge -9.56 uC is fired with an initial speed of 97.2 m/s directly toward the fixed charge. What is the distance of closest ...

**properties and mental math**

use properties and mental math to find the value of (86 + 27) + 3

**Physics**

Two charges are placed on the x axis. One of the charges (q1 = +8.71C) is at x1 = +3.00 cm and the other (q2 = -28.6C) is at x2 = +9.00 cm. Find the net electric field (magnitude and direction given as a plus or minus sign) at (a) x = 0 cm and (b) x = +6.00 cm. Please help!

**college physics**

Two charges are placed on the x axis. One of the charges (q1 = +8.71C) is at x1 = +3.00 cm and the other (q2 = -28.6C) is at x2 = +9.00 cm. Find the net electric field (magnitude and direction given as a plus or minus sign) at (a) x = 0 cm and (b) x = +6.00 cm. Please help!

**Chemistry**

a solution is 0.0300 m in Sodium. How many grams of sodium carbonate are necessary to prepare 900.0 ml of this solution? I don't know where to start on this.

**chemistry**

order Se, S, As, by increasing atomic radius? explain why?

**chemistry**

a buffer is a substance which? a) accepts OH- in basic solution b) accepts H+ in acid solutions

**chemistry**

whats an example of hydrogen bonding?

**math**

I don,t know that what I am trying to firgure that oug. I even looked in a math book. Nothing. T

**math**

what is 8x3x3 in exponential form

**chemistry**

How many moles of aluminum do 5.9×1024 aluminum atoms represent?

**physics**

A truck driver attempting to deliver some furniture travels 5 km east, turns around and travels 5 km west, and then travels 12 km east to his destination. What distance has the driver traveled?

**Maths**

I LOVE MATHS 5+5=10

**Physics**

An athlete springs a circular 400.0 m track in 50.0 s. Asume he runs a constant speed. a. What is his speed over the entire course? b. What is the magnitude of his instantaneous velocity at any point along the circuit? c. If he starts facing west and runs counterclockwise, ...

**math**

A factory can produce two products, x and y, with a profit approximated by P = I think it's b but I'm not really sure. Can someone show me how to do this or let me check my answer? :) 14x + 22y – 900. The production of y can exceed x by no more than 200 units. ...

**Algebra**

(9a^3b^4-12a^2b^5+6ab^7)/(6a^2b^3)

**environment**

The ideal study plan includes which of the following? A. Quality preparation. B. Use of as much different intelligence as possible. C. Both A & C. D. An elaborate study environment.

**readind**

Which is the best way to learn new material? A. Consistently study the same way. B. Review notes every day. C. Use techniques that appeal only to your preferred learning style. D. Use techniques that appeal to all three learning styles.

**science**

Na and K have low ﬁrst and high second ionization potentials, whereas Mg and Ca have low values for both ﬁrst and second potentials. These observations suggest that

**math probability**

Assume that Pr[E]=0.55,Pr[F]=0.55,Pr[G]=0.55,Pr[E∪F]=0.85,Pr[E∪G]=0.8, and Pr[F∪G]=0.75. Find: Pr[E' U F]; Pr[F' ∩ G]; and Pr[E ∩ G]

**english**

The chess copetition ended ob time pronoun or noun

**physics**

A jogger accelerates from rest to 5.78 m/s in 3.51 s. A car accelerates from 19.7 to 32.1 m/s also in 3.51 s. (a) Find the magnitude of the acceleration of the jogger. (b) Determine the magnitude of the acceleration of the car. (c) How much further does the car travel than the...

**physics**

A sprinter explodes out of the starting block with an acceleration of + 2.02 m/s2, which she sustains for 1.12 s. Then, her acceleration drops to zero for the rest of the race. What is her velocity at (a)t = 1.12 s and (b) at the end of the race?

**chemistry**

Thank you for your help.

**english**

Noun

**writing**

First second next last in conclusion in summary then final first of all second of all

**Physics(please help, I'm stuck)**

A particle with a charge of -1.4 μC and a mass of 2.9 x 10-6 kg is released from rest at point A and accelerates toward point B, arriving there with a speed of 22 m/s. The only force acting on the particle is the electric force. What is the potential difference VB - VA ...

**Chemistry**

C2H4(g) + H2O(l) → C2H5O(l) what is the rendition percentage if 4.50g of C2H4 produce 4.7g of ethyl alcohol?

**Physics**

I have the same problem. Please help!

**Physics**

A projectile is fired straight up at a speed of 13 m/s. How long does it take to reach the top of its motion? The acceleration due to gravity is 9.8 m/s2 .

**Probability**

An urn contains a red ball, a blue ball, an orange ball, and a yellow ball. A ball is chosen one at a time then replaced. This is done 4 times. What is the probability one of each color is chosen?

**Science**

make a statement relating hydrogen ion concentration to the acidity and basicity of solutions

**science**

If a solution A has 10,000 times as many H+ ions as solution B, what is the difference in pH units between the two solutions?

**Physics**

Have a positive slope

**Science**

5. You have made the following two solutions: X) hydrogen ion concentration = 1 x 10-5M Y) pH = 4 State which statements below are true and which are false: a. Solution X contains 1 x 10-9M hydroxide ions. b. Solution X contains more H+ ions than Solution Y. c. Solution Y ...

**Biology**

make a statement relating hydrogen ion concentration to the acidity and basicity of solutions

**Biology**

If a solution A has 10,000 times as many H+ ions as solution B, what is the difference in pH units between the two solutions?

**physics**

Both car A and car B leave school at the same time, traveling in the same direction. Car A travels at a constant speed of 78 km/h, while car B travels at a constant speed of 88 km/h. How far is Car A from school 2 h later? Answer in units of km

**Business**

Analyze and compare both data sets using the data analysis and biases concepts from Chapter 11 of Sekaran & Bougie (2010).

**physics**

You are on a hike in the mountains. You have 4.92 km left to go before your next campsite. The sun will set in 6.6 h. What avergae speed must you walk to camp at sunset? Answer in units of km/h

**algebra**

Jim is paid for overtime when he works more than 40 hours per week. Write an expression for the number of hours he works overtime when he works h hours.

**Physical Science**

Find the density in g/cm3 of a 800 cm3 piece of metal having a mass of 4 kg.

**physics**

Hello i just worked on this problem, Vf^2=Vo^2+2gh Vf- velocity final Vo-Initial velocity g-gravity h-height Vf^2=(2.60^2) + 2*(9.8)(8.70) Vf^2=177.28 square root it... 13.314m/s Subtract from heli speed, 13.314-2.60= -10.714 negative because up is positive and down well is ...

**Math**

Can you show me how

**Math**

John runs on a daily basis. He jogs 5 miles every day except Saturday. On that day he jogs 9 miles. How many miles will he jog in 4 weeks?

**Math**

Jarrod wants to save $245 to buy a Wii gaming system. If he was saving $35 each month, how long would it take him to have the needed money? 7 months? The border between Texas and Mexico is 248 miles. If there are 32 countries along the border, about how many border miles are ...

**Physics**

A ball is dropped from rest from a height of 20.0m. One second later a second ball is thrown vertically downwards. If the two balls arrive on the ground at the same time, what must have been the initial velocity of the second ball?

**Physics**

A ball is dropped from rest from a height of 20.0m. One second later a second ball is thrown vertically downwards. If the two balls arrive on the ground at the same time, what must have been the initial velocity of the second ball?

**Pre-calc**

Solve 3.3= 1.005^n

**Physics**

A hill that has a 31.4 % grade is one that rises 31.4 m vertically for every 100.0 m of distance in the horizontal direction. At what angle is such a hill inclined above the horizontal?

**Physics**

A hill that has a 31.4 % grade is one that rises 31.4 m vertically for every 100.0 m of distance in the horizontal direction. At what angle is such a hill inclined above the horizontal?

**Physics**

A rok is thrown 24 meters/sec upward and lands in a 10 meter deep hole. How long is the rock in the air until it reaches the bottom of the hole?

**psycology**

a professor gives his 100 studebts an axam and everyone gets an A. the exam lacks_______ to detect which students studied and which didn't sample size reliability power significance

**Biology**

Zack im in connections Bro

**physics**

I have been stuck on this for a while now and cant figure out what it is i am doing wrong HELP!!! A tennis ball with a velocity of 15.5 m/s is thrown perpendicularly at a wall. After strik- ing the wall, the ball rebounds in the opposite direction with a speed of 9.3 m/s. If ...

**Chemistry**

At a certain temperature, .5 mol of PCl5 was placed in a .25 L vessel and permitted to react as shown PCl5 (g) --> PCl3 (g)+ Cl2 (g) At equilibrium, the container held .1 mol of PCl5. What is the value of "K"?

**Physics**

Block A of mass 115 kg rests on a table with which it has a coefficient of limiting friction of 0.37. A light cord passes horizontally from Block A, without slipping, over a pullet of mass 34kg, radius 120 mm and radius of gyration 84mm, and down vertically of block B of mass ...

**Physics**

The drag coefficient = 0.354 The mass of car = 1200 kg rolling resistance = 180 N Air density = 1.181 kg m^-3 Frontal area = 1.88 m^2 What is the deceleration at a speed of 82 km h^-1 when the car is taken up to high speed and then allowed to coast down on a level road.

**Physics**

In a fairground ride a child of mass 37 kg stands against the inside surface of a circular cylinder of radius 3.9m that rotates around its vertical axis of symmetry. The cylinder has an angular speed of 1.3 rad/s and an angular acceleration of 0.12 rad s^-2. What is the radial...

**algebra**

x+1/3=5/6

**trig**

Imagine that you are sitting 6 feet away from a television that is hung on a wall. The top of the TV is 8 feet off the ground. Which function correctly represents the angle that you make with the top of your television?

**English**

12. A 13. D 14. D