# Serena

Popular questions and responses by Serena-
## Stats

Makers of a new pain-relieving medication claim that it relieves chronic pain faster than the current top-selling pain reliever on the market. A double-blind experiment was conducted in which 10 people who experience chronic pain were randomly selected to

*asked on May 10, 2015* -
## Math

Rewrite the expression in terms of the first power of the cosine sin^8(x) how do i do this plz help !!

*asked on February 26, 2017* -
## AP Chem

Reaction 1: NaOH + HCL --> H20 + NaCl delta H of -100.332 kj/mol Reaction 2: NaOH + NH4Cl --> NH3 + H20 : delta H of 358.639 kj/mol Reaction 3: HCl + NH3 --> NH4Cl : delta H of -51.701 kj/mol Use your answers from question 2 above and Hess's law to

*asked on October 13, 2014* -
## Technology

1. Who is an upstander? A. the person doing the bullying B. the person being bullied C. the person watching the bullying D. the person who tries to stop the bullying** 2. Which of the following is a place where cyberbullying DOESN’T occur? A. chat

*asked on March 10, 2016* -
## Differential Calculus

The base of an isosceles triangle is 10 feet long and the base angles are decreasing at a rate of 2° per second. Find the rate of change of the area when the base angles are 45°.

*asked on May 11, 2016* -
## Chemistry

Why does AgCl dissolve in NH3 but AgBr and AgI don't? KSP of AgCl = 1.8 x 10-10 KSP of AgBr = 5.0×10–13 KSP of AgI = 1.5 x 10-16

*asked on April 26, 2015* -
## Social Studies

Can someone check my responses please? I want to make sure I'm correct before submitting. The * is my response 1. How does the Pledge of Allegiance to the flag of the United States reflect the concept of natural rights? A. The Pledge of Allegiance includes

*asked on August 22, 2016* -
## Chemistry

I have discovered a new chemical compound with the formula A2B. If a saturated solution of A2B has a concentration of 4.35x10-4M. a) What is the concentration of B2- ions? b. What is the concentration of A1+ ions? c. What is the solubility product constant

*asked on March 16, 2014* -
## Differential Calculus

A clock has hands 1 and 1 3/5 inches long respectively. At what rate are the ends of the hands approaching each other when the time is 2 o'clock?

*asked on May 12, 2016* -
## Algebra

Before the final exam, a student has test scores of 72, 80, 65, 78, and 60. If the final exam counts as one-third of the final grade, what score must the student receive in order to have a final average of 76 percent? Thanks!!

*asked on September 14, 2013* -
## Calculous Pre

A population grows from 11,000 to 15,000 in three years. Enter your answers to three decimal places. Assuming the growth is exponential, find the growth rate and continuous growth rate Growth rate ______ %? Continuous rate _________ %?

*asked on October 3, 2014* -
## Social Studies

"We hold these truths to be self evident, that all Men are created equal, that they are endowed by their Creator with certain unaliable rights,..." -The Unanimous Declaration of the Thirteen United States of America Which of the following best paraphrases

*asked on August 21, 2016* -
## Healthcare Statistics

using the following information, determine if the differences between the means are significant medical terminolgy class. Group A = number of word elements remembered by students using flash cards, group B= number of word elements remembered by students

*asked on April 25, 2016* -
## Chemistry

An atmospheric scientist interested in how NO is converted into NO2 in urban atmospheres carries out two experiments to measure the rate of this reaction. The data are tabulated below. A: [NO]0 = 9.63 × 10-3 M, [O2]0 = 4.1 × 10-4 M t(s)

*asked on March 2, 2014* -
## Biology

4.0 g of ferrous ammmonium sulphate, FeSO4(NH4)2SO4 6H2O, is used. Since the oxalate is in excess, calculate the theoretical yield of the iron complex. Please help with this question. Thank you.

*asked on November 16, 2010* -
## Math

1. Which of the following is a possible measure of the area of a square rug? A. 18 square feet B. 24 square feet C. 36 square feet** D. 48 square feet 2. Based on your answer to the precious question, what would the length of one side of the rug be? A. 4

*asked on March 3, 2016* -
## Chemistry

Assume that the ionic compound CaCl2, separates completely into Ca and Cl ions when it dissolves in water. How many moles of each ion are present in the solution???

*asked on August 9, 2012* -
## chemistry

what is the hybridization of BrO2+

*asked on November 18, 2010* -
## history

1. The Inca's huge empire was located in which mountain chain? (1 point) A. Rocky Mountains B. Alps C. Andes----- D. Amazons 2. The Incan people believed their emperor was related to whom? (1 point) A. Cuzco B. Quipo C. the god of Earth D. the

*asked on September 21, 2015* -
## Precalculus

A rancher wishes to fence in a rectangular plot of land and divide it into two corrals with a fence parallel to two of the sides. If she has 300 yd of fencing available, how large an area can the plot have? This is what I have so far: A=xy 300=2x+3y

*asked on April 15, 2015* -
## Physics problems

Hi, everyone who is going to read this, thank you for trying to help me, this really means a lot to me, you are saving my behind! Ok, so here it goes: I was wondering if this information is correct; please tell me if it is not A Ferris wheel is a vertical

*asked on October 28, 2007* -
## Mathematics

A map drawn to scale of 1:50 000 with the actual distance between two points is 4.5km.Calculate the number of centimetres that should be used to represent this distance on the map.

*asked on June 15, 2009* -
## Algebra 2

If the point P is on the graph of a function f, find the corresponding point on the graph of a given function. P (0,5) y = f ( x + 2 ) - 1

*asked on October 28, 2013* -
## Math

Convert from base 10 to the indicated base. 2500 to base 14 I got CA8 to the base of 14. Is that correct?

*asked on September 22, 2010* -
## Calculus

Approximate the area under the curve on the given interval using n rectangles and the evaluation rules (a)left endpoint, (b) midpoint and (c) right endpoint. y=(x+2)^(1/2) on [1,4], n=16 How am I suppose to do this?

*asked on July 26, 2008* -
## Math algebra

To find the average of a set of test scores we divide the sum of the test scores by the number of test scores. On her first four algebra tests,Paula wests scored 88,92,97,and 96. Write an equation that can be used to determine the grade paula needs to

*asked on November 10, 2016* -
## Math

A rectangular box has a length of 12 inches and a width 4 inches. The length of the three-dimensional diagonal of the box is 14 inches. What is the height of the box?

*asked on January 30, 2014* -
## calc

If z = 2cis 60°, find z^4 in rectangular form.

*asked on January 28, 2014* -
## physics

An object having a net charge of 18.2 μC is placed in a uniform electric field of 790 N/C directed vertically upward, i.e. in the direction opposite gravity. What is the mass, in grams, of this object if it "floats" in the field? (Assume g = 9.80 m/s2.)

*asked on January 21, 2015* -
## physics

1.7 mol of an ideal gas which starts at 1.6 atm and 50 o C does 2.0 kJ of work during an adiabatic expansion. What is the final volume of the gas?

*asked on November 18, 2010* -
## physics

A container of volume 14.2 cm3 is initially filled with air. The container is then evacuated at 0oC to a pressure of 32 mPa. How many molecules are in the container after evacuation if we assume that air is an ideal gas?

*asked on November 18, 2010* -
## Math

A 12-foot ladder is set up 5 feet from the base of a building. How far up the building does the ladder reach? Round your answer to the nearest tenth of a foot.

*asked on January 30, 2014* -
## history

3. All of the following aided in the decline of the Incan Empire EXCEPT (1 point) A. being conquered by the Mayans. B. Francisco Pizzaro's trap that helped capture and kill the Incan emperor and his men. ---- C. that the Spanish had superior weapons. D.

*asked on September 21, 2015* -
## physics

The position of a 0.43 kg object attached to a spring is described by [x = (0.49 m) cos(1.25πt)] a) What is the amplitude of oscillations in m? b) What is in meters/second the maximum speed of the oscillating object? Answer in meters/seconds . c) Find in

*asked on November 11, 2014* -
## Math 10

Hello, Is there easiest and simplest way to do this question? "A baseball is thrown from the top of a building and falls to the ground below. The height of the baseball above the ground is approximated by the relation h = -5t2 + 10t + 15, where h is the

*asked on April 13, 2014* -
## 7th grade

rosa wants to buy a computer desk that originally cost $650. It has been marked down to a new price of $520. What is the percent off?

*asked on August 9, 2010* -
## history

3. All of the following aided in the decline of the Incan Empire EXCEPT (1 point) A. being conquered by the Mayans. B. Francisco Pizzaro's trap that helped capture and kill the Incan emperor and his men. C. that the Spanish had superior weapons. D. that

*asked on September 21, 2015* -
## physics

an object slides off a roof 10 m above the ground with an initial horizontal speed of 5 m per second. the time between the object's leaving the roof and hitting the ground is 1.4s. how far does it land from the wall?

*asked on October 1, 2011* -
## physics

"Calculate the internal energy for the air in human lungs after a regular inhalation. You find this volume discussed in the context of the spirometer (textbook p. 203). Hint: treat air as an ideal gas with the molecular mass M = 29.00 g/mol " Not sure the

*asked on November 18, 2010* -
## Trigonometry

An airplane is 48 miles due north of a town. An airport is 29 miles North-West of the town. It is determined that the airplane is 34 miles from the airport. On what bearing should the pilot fly to get to the airport? Please show work if possibly, I'm

*asked on November 6, 2016* -
## diameter/kg

What is the mass of water required to fill a circular hot tub 3.4 m in diameter and 1.4 m deep? Answer in units of kg.

*asked on January 4, 2016* -
## physics

If 842 J of heat is needed to increase the temperature of ethane gas (C2H6) in a 15 litre container from 237 K to 400 K, how much gas is in the container

*asked on November 18, 2010* -
## Math

The difference between two numbers is 45. Three times the larger number less five times the smaller number equals 75. What are the two numbers?

*asked on July 21, 2015* -
## Physics

A block of mass 11.2 kg slides from rest down a frictionless 24.0° incline and is stopped by a strong spring with a spring constant 31.3 kN/m (note the unit). The block slides 8.90 m from the point of release to the point where it comes to rest against

*asked on October 25, 2014* -
## physics

Find the work for an isothermal expansion of 3.08 mol of an ideal gas at temperature of 18oC from pi = 4.55 atm to pf = 3.32 atm.

*asked on November 18, 2010* -
## 5th grade Math

One tap can fill a barrel in 3 minutes and another can fill it in 6 minutes. Both taps are turned on together for 1 minute. What fravction of the barrel will be filled in 1 minute?

*asked on April 26, 2009* -
## Pre-Calculus

Verify the following identity: (sin2x)/sin - (cos2x)/cosx=secx

*asked on April 2, 2020* -
## chemistry

when 12.76mL of HCl of unknown concentration (but less than the base) are reacted with 15mL of 3.254M NaOH, 1.68kJ of heat are released. What is the molarity of the HCl solution?

*asked on November 23, 2010* -
## trigonometry

Point P (8, -4) is on the terminal arm of angle theta What quadrant would this be in? Cosine?

*asked on May 19, 2018* -
## physics

Two masses are connected by a light string passing over a frictionless pulley as shown on Figure. The M2= 6.1 kg mass is released from rest at height h = 2.8 m . We are given that M1=2.7 kg and I, the moment of inertia of the pulley is I = 0.198 kg m2 and

*asked on November 4, 2014* -
## Healthcare Statistics

Given the following p values, which would be considered more significant? p ¡Ü 0.3 p ¡Ü 0.02 p ¡Ü 0.25

*asked on April 25, 2016* -
## Science

A.) A runner is jogging at a steady 6.7 km/hr. When the runner is 3 km from the finish line, a bird begins flying from the runner to the finish line at 20.1 km/hr (3 times as fast as the runner). When the bird reaches the finish line, it turns around and

*asked on August 28, 2014* -
## Algebra 1

While playing a game, Rachel pulls two tiles out of a bag without looking and without replacing the first tile. The bag has two colors of tiles--black and white. There are 10 more white tiles than black tiles. a. Write and simplify an expression that

*asked on May 28, 2014* -
## Chemistry

So I am trying to understand in molecular terms the solubility of NaCl in water. So there are intramolecular forces that are mostly ionic between the ions, creating this partial positive, partial negative substance. And the intermolecular forces are also

*asked on May 8, 2014* -
## Physics

In a horizontal spring-mass configuration, the position of the 0.52 kg mass is described by [x = (1.09 m) sin(2.70t)] a) What is in meters the amplitude of these oscillations? b) What is in m/s the maximum speed of the mass under these conditions? c) What

*asked on November 12, 2014* -
## physics, math, science

a soccer ball is kicked on the ground at 8m/s. another player is standing 30 m away. if she needs to intercept it at 20m - how much time does she have and how fast must she run?

*asked on October 1, 2011* -
## Chemistry

Do pipettes blow up like balloons when they are heated. Why or why not?

*asked on December 16, 2013* -
## Magic Thesis Statement

Hi! I'm writing an essay about how women act according to male or female domination. Could you please look at my magic thesis and tell me if my why is well written. Thanks! By examining the gender context during Trujillo's regime, one can see that some

*asked on November 7, 2013* -
## Grammar

Which sentence is grammatically correct? Most of the European population was peasants. or Most of the European population were peasants. Thanks!!!

*asked on August 21, 2013* -
## 5th grade Math

Insert parentheses to make this sentence true. 3*8+6 squared -8/2=26. My teacher told me I think that the parentheses go around the 3 and last 8. Is that true. How did you do that?

*asked on October 2, 2008* -
## English Composition I

Argumentive Essay (3 pages) Topic question: Should future educational institutions move toward a specialized educational approach (as seen in technical school), and stray from the traditional well-rounded approach? I need help with: -What keywords would be

*asked on September 30, 2017* -
## English

Dr. Seuss is an authorwhovis famous for his original and clever children's book

*asked on April 30, 2014* -
## European History

Can you please explain this quote? "The monarchy of Rome, as it is now, is a pestilence to Christendom." -Erasmus

*asked on August 13, 2013* -
## MathLog#4

How would you solve for 'a'? (1/a) - (1/b) = c would you use the LCD???

*asked on April 2, 2012* -
## math

a pari of shoes is on sale for 10% off the original price. If the sale price is $14.40, what was the original price of the item?

*asked on August 9, 2010* -
## English

Why does Gene not have an interest in Brinker in the book A Separate Peace?

*asked on February 5, 2010* -
## physics

At a picnic, a Styrofoam cup contains lemonade and ice at 0 degree C. The thickness of the cup is 2.0*10^-3m, and the area is 0.016m^2. The temperature at the outside surface of the cup is 35 degree C. The latent heat of fusion for ice is 3.35*10^5 J/kg.

*asked on February 12, 2008* -
## Physics

A solid sphere of mass 2.07kg rolls up an incline with an inclination angle of 24.40°. At the bottom of the incline, the center of mass of the sphere has a translational speed of 2.80m/s. a) What is in J, the linear kinetic energy of the sphere at the

*asked on November 4, 2014* -
## Physics

Consider the rods plus disc system shown in the Figure. The rod has a length L =0.50 m, and mass M = 0.270kg. The large disc has a radius of R = 0.130m and mass m=0.810kg. The second disk should be treated as a point mass of 0.405kg. It is glued to the rod

*asked on November 3, 2014* -
## Chemistry

The heat capacity of aluminum is 24.4 J/mol times degrees C. How much energy is released when 5.00 g Al is cooled from 50 degrees C to 30 degrees C. a) 2440 J b) 90 J c) 3.7 J d) 488 J I said A, but the answer sheet says that the answer is B. Can someone

*asked on June 4, 2014* -
## physics

We confirm the concept of the geothermal effect in an alternative fashion to the discussion in the text. We know that the average rate at which heat is conducted through the surface of the ground in North America is 54.0 mJ/(s m2). Assuming a surface

*asked on November 23, 2010* -
## biology

How did the primordial atmosphere, photosynthesis, oxygen, the ozone layer, and the endosymbiotic theory influence the origin of living organisms?

*asked on September 2, 2009* -
## About previous Physics post/answer from Bobpursely

So do you mean to say....Ferris wheels use motors, therefore meaning that electrical energy is present. Electrical energy from the motor is then turned into kinetic energy. Electricity, generated from a switch and wires, travel through the motor which

*asked on October 29, 2007* -
## Physical Science 9th grade

Could someone please explain how I do this or provide a link explaining how. I am very confused. 1) a) Name 2 properties of waves that change if the wave changes media. b) Name a property that does NOT change when it changes media. 2) If the wavelength of

*asked on May 16, 2017* -
## Math comparing

One box holds 16 crayons.Another box holes 24 crayons.Write a sentence using words that compares the crayons in two boxes.

*asked on November 9, 2016* -
## Math

What is the factorization of... p^3 - 2p^2 -9p + 18?

*asked on August 31, 2013* -
## Geometry

Find the measure of the angle formed by the hands of a clock at 9:43. Thanks!

*asked on September 4, 2012* -
## Reading

Is there any flowers that rhymes with journal??????

*asked on May 23, 2008* -
## physcis

Two small beads having charges q1 and q2 are fixed so that the centers of the two beads are separated by a distance d shown in the figure. A third small bead of charge q=10.0 x 10-9 C is placed between both charges a distance x from q1. a) If q1 = 31.0 x

*asked on January 17, 2015* -
## physics

The position of a 0.31 kg object attached to a spring is described by [x = (0.85 m) sin(2.37πt + 0.35)] a) What is the amplitude of oscillations in m? b) What is in meters/second the maximum speed of the oscillating object? Answer in meters/seconds . c)

*asked on November 11, 2014* -
## Essay Title

Hi. I need help thinking of a title for the essay I am writing. The essay is about the Dominican Republic and Trujillo's regime. Specifically I am talking about how women who accept/deny female stereotypes accept/deny male domination. Can someone help me

*asked on November 11, 2013* -
## science

how is the mouth of a perch and earthworm specialized.. PLEASE HELP!

*asked on October 16, 2011* -
## Chemistry

A 16 oz Frappuccino from Starbucks has 54g of sugar. Calculate the concentration of sugar in percent by mass ( 1 oz = 28 g )

*asked on March 10, 2020* -
## Math

The radius of the larger circle is 9cm. The diameter of the smaller circle is 11cm. Find the area of the shaded region. I don't understand this questions at all please help.

*asked on January 27, 2017* -
## Calculus

What would the limit be for the following problems? lim (square root (x+3)) x--> 1 I thought it would be 1.4 lim (1/x) x--> 7 I thought it would be 0 or .1 but neither of those show to be correct. Thank you!

*asked on August 22, 2015* -
## physics

An m=150 g block hits an M= 265 g block initially at rest on a horizontal surface. After impact they stick together and slide 7.47 m before coming to rest. The coefficient of friction between blocks and surface is 0.39. a) What is in m/s the speed of both

*asked on November 1, 2014* -
## physica

Consider the rods plus disc system shown in the Figure. The rods are identical. They have a length L =0.50 m, and mass M = 0.250kg. The disc has a radius of R = 0.130m and mass m=0.750kg. Both rods are glued to the disk as shown with X = 0.25m. The system

*asked on October 28, 2014* -
## Cross-Multiply

9. Explain the process of cross-multiplication.

*asked on May 13, 2013* -
## science

a 1200W machine operates at 120V. what is the resistance of the machine?

*asked on May 27, 2010* -
## Physics and Dr. Bob

Not be to a nag, I was just wondering (in addition the energy section from my previous post)...in the wheel the electrical energy is present due to the motor. THis is then turned into kinetic energy, from the magnetic field that is created due to the

*asked on October 28, 2007* -
## Math 10

Algebraically, determine the vertex form of a quadratic relation, if the vertex is at (-1, 2) and the point (1, -10) is on the parabola. Show all of your steps. I know that the formula is y=a(x-h)suared+ k but how do i apply these numbers to this formula?

*asked on April 22, 2014* -
## Chemistry

Why does a pound of feathers float, but a pound of lead sink? Is it because of how dense each group is?

*asked on August 29, 2013* -
## European History

Where was this quote said, what impact did it have on society, and what changes were taking place when this quote was said. “I have the feeling that the days of Cicero and Demosthenes are much closer to me than the sixty years just passed.” -Leonardo

*asked on August 13, 2013* -
## Accounting

Can someone tell me the formula of how to calculate depreciation?

*asked on December 12, 2011* -
## physics

We consider hemoglobin along a 0.29 m long tube filled with water. The cross-sectional area of the tube is 326 mm2. The diffusion coefficient is 7 x 10^-11 m^2/s A total amount of hemoglobin of 1.22 x 10-12 g is transported in a steady rate along the tube

*asked on November 23, 2010* -
## CMC220

how each new medium affected news content and delivery, including how people engaged with news and how the media that preceded it adapted their content and delivery. Be sure to discuss newspapers, magazines, radio, TV, and satellite and Internet services.

*asked on November 8, 2009* -
## acc250

Has anyone done the Sahron Clark, accouting in Peachtree? Just wondering how to enter the supplies on hand, to the adjusted trial balance. confused about this.

*asked on September 23, 2009* -
## English (Grammar)

Would it be grammatically correct to say "Lastly, the Puritan values of appeasing towards God in every thing they do..." or "Lastly, the Puritan values of appeasing God in every thing they do..." I'm thinking the second one is grammatically correct but am

*asked on September 4, 2014* -
## Algebra

An asthma medicine is to be prepared from an elixir with a drug concentration of 5 mg/mL and a cherry flavored syrup that is to be added to hide the taste of the drug. How much of each must be used to prepare 100 mL of solution with a drug concentration of

*asked on September 16, 2013* -
## Science

What do the hairlike structures on a cell do? Please don't give me a link to another website. Thank you!

*asked on April 5, 2013*

## Pages

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