# Kristen

Most popular questions and responses by Kristen-
## Chemistry

Predict whether the following reactions will be exothermic or endothermic A) N2(g)+ 3H2(g) --> 2NH3(g) B) S(g) +O2(g) ---> SO2(g) C) 2H2O(g) ---->2H2(g) + O2(g) D) 2F(g) +F2(g) Bond H-H 432 kj/mol N-N(triple bond) 942 kj/mol O=O 494 KJ/Mol F-F 155 KJ/mol

*asked on January 22, 2012* -
## physics

a 62.0kg bungee jumper jumps from a bridge. she is tied to a bungee cord whose unstretched length is 12.0 m and falls a total of 31m a) calculate the spring constant k of the bungee cord and b) calculate the maximum acceleration she experiences.

*asked on August 10, 2014* -
## physics

a force of 20N compresses a spring with a spring constant of 50N/m. how much energy is stored in the spring?

*asked on July 23, 2014* -
## math

Find the periodic payment R required to amortize a loan of P dollars over t yr with interest charged at the rate of r%/year compounded m times a year. (Round your answer to the nearest cent.) P = 100,000, r = 9.5, t = 23, m = 12

*asked on May 9, 2012* -
## physics

NASA launches a satellite into orbit at a height above the surface of the Earth equal to the Earth's mean radius. The mass of the satellite is 550 kg. (Assume the Earth's mass is 5.97 1024 kg and its radius is 6.38 106 m.) (a) How long does it take the

*asked on September 27, 2015* -
## physics! Need help badly

A 4.65 kg object is released from rest while fully submerged in a liquid. The liquid displaced by the submerged object has a mass of 2.60 kg. How far and in what direction does the object move in 0.300 s, assuming that it moves freely and that the drag

*asked on April 18, 2012* -
## Physics

Friction provides the force needed for a car to travel around a flat, circular race track. What is the maximum speed at which a car can safely travel if the radius of the track is 80.0 m and the coefficient of friction is 0.38?

*asked on February 3, 2011* -
## algebra

You buy 10 gallons of ice cream for a party, how many cup sized containers can you fill with this?

*asked on September 30, 2015* -
## Chemistry

How many Moles of solute particles are present in 1 mL of aqueous 0.070 M (NH4)2CO3? ____ mol of Particles

*asked on November 14, 2012* -
## Chemistry

I don't know how to do Titration problems! I have an emergency homework assignment that's crucial to my grade! Please help with tips and step by step response! Please help!- 1. 50ml of 0.3 M KOH are required to titrate 60 ml of H^2SO^4. What is the M of

*asked on May 11, 2015* -
## college chemistry

If KHP sample #1 requires 27.30 mL of NaOH solution to reach an endpoint, what volume should be required for samples #2 and #3?

*asked on October 25, 2012* -
## AP Physics

A uniform spherical shell of mass M and radius R rotates about a vertical axiss on frictionless bearings. A massless cord passes around the equator of the shell, over a pulley of rotational inertia I and radius r, and is attached to a small object mass m.

*asked on January 27, 2008* -
## AP Chem

Calculate the pH after 0.010 mol gaseous HCl is added to 250.0 mL of each of the following buffered solutions: a. .050 M NH3/.15 M NH4Cl b. .5 M NH3/ 1.5 M NH4Cl

*asked on April 3, 2013* -
## Chemistry

Given that ∆Hº(Br(g)) = 111.9 kJ/mol ∆Hº(C(g)) = 716.7 kJ/mol ∆Hº(CBr4(g)) = 29.4 kJ/mol calculate the average molar bond enthalpy of the carbon-bromine bond in a CBr4 molecule.

*asked on January 23, 2013* -
## Grd 12 U English

I am the discussion director for my group. I have to grab 4 reallyyy good discussion questions for the book The Kite Runner. I already found one good question, I need the other 3. It has to be from chapter 1-3 PLEASE help me out, i'm so stuck, honestly I

*asked on July 8, 2013* -
## Chemistry

find the pH of each of the following solutions of mixtures of acids: .125M in HBr and .130 M in HCHO2, .155M in HNO2 and 9.0*10^-2M in HNO3, 5.5×10−2 in acetic acid and 5.5×10−2 in hydrocyanic acid

*asked on August 2, 2010* -
## math

Suppose payments were made at the end of each month into an ordinary annuity earning interest at the rate of 8%/year compounded monthly. If the future value of the annuity after 14 yr is $70,000, what was the size of each payment? (Round your answer to the

*asked on May 9, 2012* -
## Math HELP!!!

I’m a Connexus Student and I need help on lesson 10: Prisms and Surface Area

*asked on February 3, 2019* -
## AP PHYISCS

A paratrooper fell 380m from an airplane without being able to open his chute but happened to land in snow, suffering only minor injuries. Assume that his speed at impact was 58 m/s(terminal speed), that his mass (including gear) was 90 kg, and that the

*asked on January 12, 2008* -
## apush

how did each of the following encourage social reform: second great awakening, industrialization, nostalgia for the past?

*asked on November 29, 2011* -
## AP Physics

A record turntable is rotating at 33 and 1/3 rev/min. A watermelon seed is on the turntable 7.5 from the axis of rotation Calculate the acceleration of the seed assuming that it does not slip? Suppose that the turntable achieves its angular speed by

*asked on January 27, 2008* -
## physics

a cue stick strikes a stationary pool ball, exerting an average forece of 50 N over a time of 7 milliseconds. If the ball has mass .1kg, what speed does it have just after impact?

*asked on January 14, 2008* -
## Physics

Whenever two Apollo astronauts were on the surface of the Moon, a third astronaut orbited the Moon. Assume the orbit to be circular and 160 km above the surface of the Moon, where the acceleration due to gravity is 1.42 m/s2. The radius of the Moon is 1.70

*asked on October 2, 2012* -
## Science

PLEASE CHECK MY ANSWERS!! I AM SOO FAR BEHIND IN THIS CLASS! 1. Which of the following describes the effect of high altitude on climate? Rain is very rare Flooding is more likely Temperatures are lower

*asked on November 21, 2018* -
## CHEMISTRY

Hydrogen gas and iodine gas react via the equation, H2 + I2 2HI, and K=76 at 600K. If 0.05 mole of HI is placed in a flask at 600K, what are the equilibrium concentrations of HI, I2, H2? I am very lost at where to even start with this problem

*asked on March 18, 2012* -
## science

How many grams of NH3, are required to produce 5.23 g HF?

*asked on March 31, 2010* -
## Physics

"Rocket Man" has a propulsion unit strapped to his back. He starts from rest on the ground, fires the unit, and accelerates straight upward. At a height of 16 m, his speed is 5.0 m/s. His mass, including the propulsion unit, has the approximately constant

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

A 78 cm long, 0.8 mm diameter steel guitar string must be tightened to a tension of 1600 N by turning the tuning screws. By how much is the string stretched?

*asked on March 14, 2012* -
## College Chemistry

A heat lamp produces 22.5 watts of power at a wavelength of 6.0 Mu.How many photons are emitted per second? (1watt= 1J/s )

*asked on February 4, 2012* -
## algebra

A worker is exposed to 98 dB for five hours and 82 dB for a three hours, giving an eight hour working day. On average what noise level is this worker exposed to? (round to the nearest whole number)

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

In order for hurricane or tropical storm to develop the temperature of the ocean must be A) 20 degrees F B) 40 degrees F C) 60 degrees F D) 80 degrees F

*asked on January 31, 2019* -
## Chemistry

Write the equation for the dissolution of NH4NO3 in water. If 5.95 mol of NH4NO3 are dissolved, how many total moles of ions are produced? Answer in units of mol

*asked on March 13, 2014* -
## Chemistry

The half-life for the first-order conversion of A to B is 56.5 hours. How long does it take for the concentration of A to decrease to 10.0% of its original amount? Our professor has given us the answer - 188hr but I am not entirely sure how he got it.

*asked on February 23, 2014* -
## physics

a force F is applied in horizontal to a 10kg block. the block moves at a constant speed 2m/s across a horizontal surface. the coefficient of kinetic friction between the block and the surface is 0.5. the work done by the force F in 1.5 minutes is?

*asked on July 23, 2014* -
## chemistry

When magnesium is heated in air, it reacts with oxygen to form magnesium oxide. 2Mg + O2 --> 2MgO If the mass of the magnesium increases by 0.335 g, how many grams of magnesium reacted? A. 0.882 B. 0.441 C. 0.509 D. 1.02 E. Not enough Info

*asked on July 5, 2010* -
## Medical Term

I need some help with medical terms. I need to determine the word parts and the definition and I'm having a hard time with these 2. stomatoesophagogastroenterocolitis cardiosphygmopneumographologist

*asked on September 16, 2015* -
## math

the bag contains 20 red marbles and30 white marbles and 40 blue ones what is the ratioof red to blue marbles what is the ratio of white to red if one marble is drawn from the bag what is the probability that the marble will not be white??? need ansewr

*asked on April 8, 2012* -
## Physics

A ball weighing 50N is pulled back by a rope to an angle of 20 degrees (the rope that the ball hangs from). Find the tension in the pulling rope.

*asked on October 7, 2012* -
## AP physics

A uniform spherical shell of mass M and radius R rotates about a vertical axiss on frictionless bearings. A massless cord passes around the equator of the shell, over a pulley of rotational inertia I and radius r, and is attached to a small object mass m.

*asked on January 27, 2008* -
## PreCalc

The half-life of krypton-91 (91Kr) is 10 s. At time t = 0 a heavy canister contains 5 g of this radioactive gas. (a) Find a function m(t) = m02−t/h that models the amount of 91Kr remaining in the canister after t seconds.

*asked on December 4, 2016* -
## math

the maximun height of a ferris wheel is 35m. the wheel takes 2 mins to make one revolution. passengers board the ferris wheel 2m above the ground at the bottom of the rotation. a. write an equation to model this b. how high is the passengers after 45s c.

*asked on July 25, 2011* -
## Math

What is the smallest counting number n so that 375n is a perfect square?

*asked on January 22, 2014* -
## math

find the sum of the measures of the intieior angles of each polygon. -hexagon -pentagon -quadrilateral -octagon -16-gon -27-gon The key is the sum of the measures. All of these figures have the same total number of degrees in their interior angles. What do

*asked on March 12, 2007* -
## AP Physics

An airplane in a horizontal circle at a speed of 130.5556 m/s. If its wings are tilted 40 degress to the horizontal, what is the radius of the circle in which the plane is flying? Assume that the required force is provided entirely by an "aerodynamic lift"

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

a 62.0kg bungee jumper jumps from a bridge. she is tied to a bungee cord whose unstretched length is 12.0 m and falls a total of 31m a) calculate the spring constant k of the bungee cord and b) calculate the maximum acceleration she experiences.

*asked on August 9, 2014* -
## Algebra 2

The loudness L of sound in decibels is given by L= 10log (l/lo) where l is the intensity of sound and lo is the intensity of the least audible sound. If lo= 10^-12 w/m^2, about how many times more intense is a 108 decibel sound than a 100 decibel sound?

*asked on February 27, 2019* -
## Tech Business

PLEASE HELP!! I'm so behind. Are my answers correct? This is my last class to pass to graduate, and I have a hard time with it. 1. Which of the following Web 2.0 tool can aid in searches using key words? A) Blogging B) Podcasting C) Tagging(My answer) D)

*asked on September 19, 2018* -
## math

one sixth of five dozen computers were shiped how many were not shiped b what was the ratio of computers were shipped to those that were not shipped c what percent of computers were shiped

*asked on March 26, 2012* -
## Physics

A student drops a stone from the edge of a sea cliff. The sound of the stone striking the ocean is heard 3.8s after the stone is released. The speed of sound in air is 340m/s. Find the height of the cliff. Ignore air resistance.

*asked on November 1, 2018* -
## Math

A box can hold 175 cubic inches of cereal. Of the box is 7 inches long and 2.5 inches wide, how talk is it ?

*asked on April 26, 2016* -
## Chemistry

Describe, in detail, how to make 5.5 liters of a 2.5 molar HCl solution from a 10.5 molar HCl stock solution.

*asked on February 22, 2011* -
## geometry

A grain storage tank is in the shape of a cylinder covered by half a sphere. The height of the cylinder is 50 feet and its diameter is 80 feet. find the total surface area (including the base) and volume of the tank.

*asked on April 21, 2009* -
## Physics Honors

A car travels due east with a speed of 60.0 km/h. Rain is falling vertically with respect to the Earth. The traces of the rain on the side windows of the car make an angle of 45.0° with the vertical. Find the velocity of the rain with respect to the car

*asked on October 16, 2010* -
## Duration

Find the duration of a 6% coupon bond making annual coupon payments if it has three years until maturity and a yield to maturity of 6.5%. What is the duration if the yield to maturity is 10.5%?

*asked on April 10, 2014* -
## Physics

A traffic light hangs from a pole as shown. The uniform aluminum pole AB is 7.70m long and has a mass of 11.0kg. The mass of the traffic light is 27.5m. 1. Determine the tension in the horizontal massless cable CD. 2. Determine the vertical and horizontal

*asked on November 2, 2012* -
## Chemistry

If 20ml of glacial acetic acid (pure HC2H3O2) is diluted to 1.5L with water, what is the pH of the resulting solution. The density of glacial acetic acid is 1.08g/ml

*asked on August 2, 2010* -
## science

If a temperature increase from 19.0 degrees C to 36.0 degrees C triples the rate constant for a reaction, what is the value of the activation barrier for the reaction?

*asked on March 13, 2011* -
## Chemistry

Suppose that you are planning a backpacking trip and will need to boil 40 L of water for your group. What volume of fuel should you bring? Assume each of the following: the fuel has an average formula of C7H16; 15% of the heat generated from combustion

*asked on October 31, 2010* -
## geometry

The limestone blocks from which an ancient pyramid was made weigh about 2 tons per cubic yard. Find the approximate weight of the pyramid having a square base of length 250 yards and a height of 150 yards.

*asked on April 21, 2009* -
## precalc

Eliminate the parameter and write the corresponding rectangular equation. X=2cos theta, y=4sin theta

*asked on February 24, 2008* -
## AP PHYSICS

A .35 kg ladle sliding on a horizontal frictionless surface is attached to one end of a horizontal spring (with the spring constant (k) =455 N/m) whose other end is fixed. The mass has a kinetic energy of 10 J as it passes through its equilibrium position

*asked on November 18, 2007* -
## Physics

A 1440-kg crate of cabbages is laid on a level, frictionless track at the end of a heavy spring. The spring is compressed a distance of 0.100 m by a force of 83500 N. When the spring is released, it propels the crate. the spring constant of the spring

*asked on April 4, 2011* -
## chemistry

2. Methanol, CH3OH, is used as fuel in race cars. This liquid fuel can be synthesized using the following process C(s)+ ½ O2(g) + 2H2(g) CH3OH(l) Calculate delta G using the deta Gf of the reaction. Calculate Kp. What is the relation between the

*asked on April 15, 2010* -
## chemistry

A compressed gas cylinder contains 1.00 103 g of argon gas. The pressure inside the cylinder is 2035 psi (pounds per square inch) at a temperature of 15°C. How much gas remains in the cylinder if the pressure is decreased to 610. psi at a temperature of

*asked on April 14, 2010* -
## AP physics

do you guys have an someone that good with advanced physics, because i have a few problems that i am not sure how to do and its for my AP physics class, and I wasn't sure if you had someone on board now that could help thanks

*asked on January 27, 2008* -
## algebra

Julie the Jeweler has fifteen gold necklaces worth $120 each, nine silver necklaces valued at $90 each, ten plated necklaces valued at $60 each and thirty beaded necklaces worth $15 each. What is the average value of a necklace at Julie’s shop? (round to

*asked on September 22, 2015* -
## algebra

An “A” is considered 4.0, a “B” is 3.0, a “C” is 2.0, a “D” is 1.0, and an “F” is 0. In your first semester you received the following grades. Calculate your grade point average English = credits 3.0 Grade = C Biology = credits 4.0

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

a long jumper takes off at an angle of 20 degrees with the horizontal and reaches a maximum height of 0.55 meters at mid- flight. how far did she jump?

*asked on June 27, 2014* -
## Math

A commercial refrigerator unit accidentally releases 12.5 L of ammonia gas at SATP. Determine the mass and number of molecules of ammonia gas released. Please if possible show the steps because I have an exam in an hour and I was trying this question and

*asked on June 21, 2013* -
## physics

A 3.00-liter aluminum cylinder at 5.00°C is filled to the brim with gasoline at the same temperature. If the aluminum and gasoline are warmed to 52.0°C, how much gasoline spills out? [Hint: Be sure to account for the expansion of the container. Also,

*asked on June 13, 2011* -
## Physics

Please help I've attempted this problem various ways and I can't seem to get the correct answer. A 69.0 kg person throws a 0.0410 kg snowball forward with a ground speed of 35.0 m/s. A second person, with a mass of 60.0 kg, catches the snowball. Both

*asked on June 3, 2011* -
## AP PHYSICS..so lost

An elevator and its load have a combined mass of 1550 kg. Find the tension in the supporting cable in Newtons when the elevator , originally moving downward at 11 m/s, is brought to rest with constant acceleration in a distance of 43 m.

*asked on October 15, 2007* -
## algebra

On a quiz worth 5 points, four students earned a 5, seven students earned a 4, six students earned a 3, two students earned a 2, and one student earned a zero. Find the average score. (round to one decimal place)

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

An airplane is flying at an airspeed of 500 km/hr in a wind blowing at 50 km/hr toward the southeast. In what direction should the plane head to end up going due east? (Round your answer to two decimal places.)What is the airplane's speed relative to the

*asked on August 28, 2015* -
## Finance

A bond currently sells for $1,120, which gives it a yield to maturity of 5%. Suppose that if the yield increases by 25 basis points, the price of the bond falls to $1,070. What is the duration of this bond?

*asked on April 10, 2014* -
## Pre calculus

Tanx + sinxsecx/ cscxtanx

*asked on February 10, 2013* -
## Physics

A 1440-kg crate of cabbages is laid on a level, frictionless track at the end of a heavy spring. The spring is compressed a distance of 0.100 m by a force of 83500 N. When the spring is released, it propels the crate. the spring constant of the spring

*asked on April 11, 2011* -
## trig

establish the identity: cot(A-B)= cotAcotB+1/cotB-cotA thanks for any help at all

*asked on July 16, 2008* -
## Chemistry

Calculate the wavelength of light if 1.50 mol of photons has an energy of 125 kJ. 6.02x10^23 things=1.00 mol(things) c=3.00x10^8 m/sec h=6.626x10^-34 J sec

*asked on February 28, 2013* -
## human anatomy and physiology

3. Critical to life is the function of the cell membrane and its ability to move materials across the cell membrane. Define each of the following in detail using diagrams to aid the understanding of the process. a) diffusion b) osmosis c) facilitated

*asked on August 23, 2005* -
## Calculus

Find two positive numbers that satisfy the requirements: "The product is 147 and the sum of the first number plus three times the second number is a minimum."

*asked on November 4, 2013* -
## Physics

A constant force of 35.9 N, directed at 28.7o from horizontal, pulls a mass of 14.7 kg horizontally a distance of 3.41 m. Calculate the work done by the force.

*asked on October 20, 2013* -
## Physics

A constant force of 35.9 N, directed at 28.7o from horizontal, pulls a mass of 14.7 kg horizontally a distance of 3.41 m. Calculate the work done by the force.

*asked on October 20, 2013* -
## communication

Please HELP!! Question 1 of 20 5.0 Points Which of the following would be the LEAST appropriate in the closing paragraph of a negative message? A. "Let us know if model #A01 would be a suitable substitution." B. "Our layaway plan will enable you to

*asked on February 4, 2013* -
## chemistry

a 230.0ml sample of a 0.275 molarity solution is left on a hot plate over night the folowing morning the solution is 1.5 molarity. what volume of solvent has evaportated from the 0.275 molarity solution?

*asked on June 21, 2012* -
## Physical Science

The string of a certain yo-yo is 80 cm long and will break when the force on it is 10 N. What is the highest speed the 200 g yo-yo can have when it is being whirled in a circle? Ignore the gravitational pull of the earth on the yo-yo.

*asked on January 31, 2012* -
## Physics

We consider the case shown in the figure below. Two objects with masses m and M are connected with a taut string running over a pulley. The pulley rotates without friction. The two masses are given as M = 6.23 kg and m = 2.54 kg. A second taunt string

*asked on October 4, 2011* -
## Physics

Find the final velocity of the two balls if the ball with velocity v2i = -19.5 cm/s has a mass equal to half that of the ball with initial velocity v1i = +26.8 cm/s. PLEASE HELP IVE TRIED EVERYTHING!!!

*asked on June 3, 2011* -
## Chem 116

How do I calculate 25.00mL of 5.0*10^-4 M of FeSCN^2+ using 0.002 M Fe(NO3)3, 0.002 M KSCN, 0.1 M of HNO3 and water?

*asked on February 25, 2010* -
## AP Physics...ahaha

A drowsy cat spots a flowerpot that sails first up and then down past an open window. The pot was in view for a total of .43 s, and the top-to-bottom height of the window is 2 m. How high aboe the window top did the flowerpot go?

*asked on September 9, 2007* -
## physics

a man stands on the roof of a 15.0m tall building and throws a rock with a velocity of magnitude 30.0m/s at an angle of 33 degrees above the horizontal. ignoring resistance calculate the horizontal distance from the base of the building to the point where

*asked on June 27, 2014* -
## Math

Four hoses are filling a pool. The first hose alone would fill the pool in 4 hours while the second hose takes 6 hours. The third hose and the fourth hose each take 8 hours to fill the pool. How long would it take to fill the pool if all 4hoses are turned

*asked on November 20, 2013* -
## English (Ms.Sue please answer) I did some work own

Ok so Im thinking I will use the theme of heroism (which is the human condition) My arguments would be character, social position and ancestry This is a book and movie comparative essay... I have to do a comparative essay on a book and a film (I chose The

*asked on July 21, 2013* -
## physics

As a train moves away from you, the frequency of its whistle is determined to be 475Hz. If the actual frequency was 500 Hz and the speed of sound in air is 350m/s, what is the Train's speed? answer is 18.4m/s please show and explain steps

*asked on July 17, 2013* -
## physics

You need to determine the density of a ceramic statue. If you suspend it from a spring scale, the scale reads 35.4 N. If you then lower the statue into a tub of water, so that it is completely submerged, the scale reads 12.4 N. What is the density?

*asked on April 11, 2012* -
## physics

A diver, below the surface of a lake, notices that no light appears to be coming toward her greater than the angle è, measured from the vertical. If the index of refraction of water is 1.33, what is the angle è (which is the critical angle of total

*asked on November 28, 2011* -
## Physics

A load of 54 N attached to a spring hanging vertically stretches the spring 4.9 cm. The spring is now placed horizontally on a table and stretched 14 cm. What force is required to stretch it by this amount?

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

Nine consecutive odd whole numbers sum to 243. Find the sum if the first and last whole numbers in this nine-addend ser.

*asked on December 17, 2013* -
## Math

An initial deposit of $5000 earns 5.5% annual interest compounded semiannually. How much will be in the account after 5 years?

*asked on December 15, 2012* -
## Chemistry

35 grams of sodium phosphate are mixed with enough water to make 3.5L of solution having a densityof 1.045g/mol. Find the concentration of sodium phosphate in ppm. Using the same information, find the molarity of the sodium and phosphate ions.

*asked on February 15, 2012*