Friday
November 28, 2014

Posts by Luis


Total # Posts: 212

chemistry
Calculate the freezing point of a water solution at each concentration. 1.40m? What are the steps to calculate this?
November 19, 2014

chemistry
What is the molarity of ZnCl2(aq) that forms when 18.0g of zinc completely reacts with CuCl2(aq) according to the following reaction? (Assume a final volume of 165mL .) Zn(s)+CuCl2(aq)→ZnCl2(aq)+Cu(s)
November 19, 2014

chemistry
V1= 38.8 n1= 1.60*10^-3 V2= 49.9 n2= ? How do we solve for n2 using avogadro's law?
October 31, 2014

chemistry
Yes, that is true but in my notes the professor never gave us a formula to figure it out. It is asking for an exact number of collisions.
October 30, 2014

chemistry
Imagine that you have an ideal gas in a 8.00L container, and that 2850 molecules of this gas collide with a square-inch area of the container at any given instant. If the volume is increased to 56.0L at constant temperature, how many collisions will occur per square inch of ...
October 30, 2014

Chemistry
Ho w
much 
water
 would 
you 
need 
to
 add
 to

500
mL
 of 
a 
0.3
M
 calcium
 nitrate 
solution
 to 
make the
 solution
 0.1
M? A.
...
October 17, 2014

chemistry
Calculate the theoretical yield of alum if 0.200g of Aluminum was reacted with excess KOH and H2SO4? I don't even know how to start it. Please help. Also I wanted to say thank you for the help I've gotten from this website it has helped me a lot. I feel like I'm ...
October 16, 2014

chemistry
It's asking for it in nanoseconds is there a change in the formula?
October 13, 2014

chemistry
How long does it take light to travel each of the following distances 2462 mi, the distance between Los Angeles and New York. How do we calculate how fast light travels?
October 13, 2014

chemistry
Can you show me how you finished the equation?
September 30, 2014

chemistry
Complete and balance each of the following equations. K2SO4(aq)+BaBr2(aq)→ Would it be K2SO4(aq)+BaBr2(aq)→K2Br2 +SO4Ba? Express your answer as a chemical equation. Enter no reaction if no precipitate is formed. (How can we know if a solid is formed in the product?)
September 30, 2014

Personal Finance (Math)
Becka borrowed $100 from her cousin at the rate of 6% per year. If the inflation rate was 2% that year, what is her cousin's actual rate of return on the loan? How do you work this out?
September 27, 2014

chemistry
A 4.78-g sample of aluminum completely reacts with oxygen to form 6.67 g of aluminum oxide Use this data to calculate the mass percent composition of aluminum in aluminum oxide. (Sorry need help with this!)
September 27, 2014

Chemisty
How many grams of Cl are in 38.0g of CF2Cl2? I really want to figure out how to do it. I can't seem to understand any of this Chem homework and it's getting me frustrated, please help!
September 26, 2014

math
A Norman window has the shape of a rectangle surmounted by a semicircle. If the perimeter of the window is 16.200 ft. give the area A of the window in square feet when the width is 3.000 ft.
September 6, 2014

Physics, Math
A typical volume of a modern hot air balloon is 2500 cubic metres, and a typical maximum temperature of the hot air is 120 degrees Celsius. Given these figures, and an outside air temperature and density of 15 ∘C and 1.225 kg/m3 respectively, compute the maximum mass (in...
September 2, 2014

Physics
A red ball is thrown down with an initial speed of 1 m/s from a height of 27 meters above the ground. Then, 0.6 seconds after the red ball is thrown, a blue ball is thrown upward with an initial speed of 24.5 m/s, from a height of 0.7 meters above the ground. The force of ...
August 28, 2014

algebra
The following equation is used to find c, the total cost for printing a quantity of high school yearbooks, b. c=5b+200
June 12, 2014

Physics
June stands on the roof of the house which is 22.8 m high and she throws the ball at an initial speed of 4.90 m/s downward at Ben who is 1.80m tall. a) With what speed does she hit her target's head and b) how much time was it in the air? Displacement= 21 m. -Place ...
June 7, 2014

Physics
Frank is traveling the posted speed limit of 36 mi/hr in a school zone. A deer darts out between two cars. He instantly hits the brakes and the car decelerates at a rate of 5.0 m/s^2. a) how much stopping distance will he require in (meters)? b) If he was going twice the ...
June 7, 2014

math last set up
To secure a 618 meter radio tower against high winds, guy wires are attached to a ring 10 meters from the top of the tower. Each wire is anchored 90 meters from the base of the tower. Find the measure of the angle the wire makes with the ground. Round your answer to the ...
May 22, 2014

math
bystander at the Pegasus Parade, is lying on his back and observing a large balloon of a cartoon character, floating directly above Broadway Street. He is located 32 feet from a point on the street directly beneath the balloon. To see the top of the balloon, he looks up at an ...
May 22, 2014

Math
Show 2/4 of the set. How many counters?
April 16, 2014

AP Biology
Why are Eukaryotes more difficult to Transform than Prokaryotes? What methods can be used to transform Eukaryotes?
April 14, 2014

AP Biology
What is the purpose of using a plasmid containing an antibiotic resistance gene in the transformation process?
April 14, 2014

math
A stone is dropped from a cliff 344 feet high. after how many seconds will it be 200 feet above the ground?
April 11, 2014

Math, Geometry
The percent grade of a highway is the amount that the highway raises or falls in a given horizontal distance. For example, a highway with a four percent grade rises 0.04 mile for every 1 mile of horizontal distance. a. How many feet does a highway with a six percent grade rise...
April 4, 2014

Math, Geomertry
A piece of a broken wheel is shown. It was taken to a machine shop to be replaced with a new “whole” wheel. Find the radius of the wheel AC=10cm, BD=3 cm and D is the midpoint of AC. Round to the nearest hundredth.
April 4, 2014

Math, Geomertry
Thank you
April 4, 2014

Math, Geomertry
A total solar eclipse occurs when the moon passes between the earth and the sun, and the darkest shadow cast by the moon, called the umbra, hits the surface of the earth. If the umbra does not hit the surface, as shown in the following figure, then a total solar eclipse is not...
April 4, 2014

Precalculus
Find a unit vector in the direction of the given vector. w=-i-2j Sorry I messed up it was not a one it was a i.
April 3, 2014

Precalculus
Find a unit vector in the direction of the given vector. w=-1-2j
April 3, 2014

Pre calculus
I got (1/Square root of 2,-1/square root of 2) Thanks
April 3, 2014

Pre calculus
Find a unit vector in the direction of the given vector. v=(1,-1)
April 3, 2014

Pre calculus
thank You
April 3, 2014

Pre calculus
P=(-2,2) Q=(3,4) S=(2,-8) PS-3PQ Find the component form and magnitude of the vector.
April 3, 2014

Pre calculus
For the most part, will a law of cosines always be one triangle? As in one triangle to solve?
March 26, 2014

physics
A car entering the freeway accelerates from 10.2 m/s with a constant acceleration of 4.4 m/s2. What is the car’s final velocity when it merges onto the highway and reaches its cruising speed 4.2 seconds later? A 28.7 m/s B 11.2 m/s C 18.5 m/s D 8.28 m/s
March 25, 2014

PHysics XXX
An airplane travels 330 m down the runway before taking off. Assuming that it has constant acceleration, if it starts from rest and becomes airborne in 9.00 s, how fast (in m/s) is it moving at takeoff? A 73.3 m/s B 36.7 m/s C 1490 m/s D 660 m/s
March 25, 2014

AP Biology
The one-pod condition (P) is dominant to the three pod condition (p). Normal leaf (L) is dominant to wrinkled leaf(l). Determine the genotypes for the two parents for all possible matings producing the following: 150 one pod normal, 147 one pod wrinkled, 51 three pod normal, ...
March 14, 2014

Pre - calculus
what happens to the cosine on the right side, when its in this step cos^3x/sinx + cosxsinx^2/sinx
March 5, 2014

Pre - calculus
Can someone please explain how to simplify this proiblem: cotx/sec^2 + cotx/csc^2
March 5, 2014

Math
How does: sin^2(x) - cos^2(x) = 1 - 2cos^2(x)
March 3, 2014

Math
Thank You
March 3, 2014

Math
(cosx - sinx)^2 + (cosx + sinx)^2 = 2 Iam in this step: 2cos^2(x) + 2sin^2(x) = 2 How can I make the equation on the right equal 2
March 3, 2014

Science - Please Check my Answer 2
A fish swims 12.0 m in 5.0 s. It swims the first 4.0 m in 2.0 s, the next 3.0 m in 1.2 s, and the last 5.0 m in 1.8 s. What is the average velocity of the fish during the time interval between 0.0 s and 3.2 s?
February 27, 2014

Math
629
October 28, 2013

geometry
Given: FG (SEG) bisects BT (SEG) BO=7x-6 OT=5x+10 Prove: BO=50
September 19, 2013

geometry
Given: FG (SEG) bisects BT (SEG) BO=7x-6 OT=5x+10 Prove: BO=50
September 19, 2013

math
User: Ariana Bouillon In Course: M/J Mathematics 2 V9 ( 2820) Instructor: Mrs. Susan Lafferty 08.03 Experimental Probability Warning: There is a checkbox at the bottom of the exam form that you MUST check prior to submitting this exam. Failure to do so may cause your work to ...
August 1, 2013

geo
Jackson is creating a water garden surrounded by a triangular patch of grass. If the pond will take up the space indicated by the circle, how many square feet of sod will he need to complete the garden (use 3.14 for and round your answer up to the next foot)?
May 9, 2013

Math
How much farther did chris run on thursday than on wednesday? If he run 3 5/8 on thursday an 1 1/4 on wednesday
May 8, 2013

math
Mrs. Browns girls scout troop had a carwash to earn some funds. they saved 1/6 of the money. They used 1/2 of the money to go horseback riding. They then had $100 left. How much did they initially make washing cars/
April 18, 2013

Math
If 9m+5=2m+26, what is the value of m?
April 17, 2013

Trig
How do I find the exact value of sin (pi/24)?I am crying
March 17, 2013

trig
Do I subtract ?
March 17, 2013

trig
I really need help . I find this hard Steve .
March 17, 2013

trig
I applied the half angle formula for sin and I got the square root of 2 minus the square root of 3 divided by 2 . and for cos I got thesqurof 2 plus thesqr of3divided by 2 .
March 17, 2013

trig
I am not under standing could you show me ? to tell me ?
March 17, 2013

trig
How do I find the exact value of sin (pi/24)?
March 17, 2013

Math
An oil-drilling company knows that it costs $25,000 to sink a test well. If oil is hit, the income for the drilling company will be $375,000. If only natural gas is hit, the income will be $165,000. If nothing is hit, there will be no income. If the probability of hitting oil ...
March 13, 2013

math
what formula i need to use in solving binomial theorem and what is the first step i need to do?
March 8, 2013

Management
operational planning sets up work schedules, routine work procedures, and timetable
February 16, 2013

math
what formula use in solving or finding for the 9th term of a number in arithmetic series and sequences?
February 16, 2013

math
what method i need to use in solving arithmetic and geometric sequences and series?
February 16, 2013

physics
An engine moves a motorboat through water at a constant velocity of 22 meters/second. If the force exerted by the motor on the boat is 5.75 × 103 newtons, what is the power of the motor?
January 11, 2013

health
i'm pretty sure it's c.
January 3, 2013

chemistry
Chemical analysis of a silicon crystal reveals gallium at a level of 3.091×10−3 atomic percent. Assuming that the concentration of thermally excited charge carriers from the Si matrix is negligible, what is the density of free charge carriers (free carriers/cm3) in ...
December 14, 2012

chemistry
thanks a lot
December 14, 2012

chemistry
You wish to increase the carbon content of a slab of steel by exposing it to a carburizing atmosphere at elevated temperature. The carbon concentration in the steel before carburization is 490.5 ppm and is initially uniform through the thickness of the steel. The atmosphere of...
December 14, 2012

CHEMISTRY
You are conducting experiments with your x-ray diffractometer. (a) A specimen of molybdenum is exposed to a beam of monochromatic x-rays of wavelength set by the Kα line of silver. Calculate the value of the smallest Bragg angle, θhkl, at which you can expect to ...
December 14, 2012

chemistry 122
c
December 11, 2012

chemistry 122
B
December 11, 2012

Chemistry
Arrange the different types of forces in order of increasing energy. Covalent, Hydrogen Bonding, Ion-Dipole, Dipole-Dipole, Induced Dipole-Dipole (induced and London dispersion), and Ionic Bonding
December 3, 2012

physical education
how do you know when you are growing
November 28, 2012

math
how i can see the exact solution of 6y-12y=12 and4x-12y=8
November 11, 2012

English
Headstrong
November 5, 2012

physics
A beam of protons is moving toward a target in a particle accelerator. This im trying to study for my exam by doing problems, however im stuck with this one. any help is appreciated beam constitutes a current whose value is 0.39A. (a) How many protons strike the target in 14 ...
September 26, 2012

Physics
A battery has an internal resistance of 0.42. A number of identical light bulbs, each with a resistance of 31.500, are connected in parallel across the battery terminals. The terminal voltage of the battery is observed to be one-half the emf of the battery. How many bulbs are ...
September 26, 2012

Physic
You must show your work for full credit.) Calculate the average speed of an oxygen molecule (with a mass of 5.3e-26 kg) at room temperature (300 Kelvin):
July 22, 2012

Physic
The tidal interaction between the Earth and the Moon has caused:
July 22, 2012

Physic
While surface conditions differ greatly, name the three ways that Venus and Earth are indeed sister planets.
July 22, 2012

Physic
Calculate the average speed of an oxygen molecule (with a mass of 5.3e-26 kg) at room temperature (300 Kelvin)show your work
July 22, 2012

astronomy
big bang theory define
July 15, 2012

Physic
How can we describe some object in astronomy? Can we either prove or disprove a hypothesis? If not, what can we do? How have theories developed over time?
July 15, 2012

Physic
How can we describe some object in astronomy? How can we interpret data? Can we either prove or disprove a hypothesis? If not, what can we do? How have theories developed over time? Explain and provide some examples.
July 15, 2012

Physic
Before continuing we need a little more information about the angle factor given in the formula above. It turns out that the angle factor is equal to the cosine of the angle that the light strikes the surface as measured from perpendicular. In this question, the angle factor ...
July 15, 2012

pHYSIC
5. Now, wait until the planet is at the winter solstice (12:00am). a) How many hours of daylight are there on the winter solstice with the inclination at 45 degrees? Use the same criteria for the length of day that you used for the previous question. b) Use the above formula ...
July 15, 2012

pHYSIC
Now let us consider the length of time that the Sun is visible. Wait until the planet is at the summer solstice (12:00am). a) How many hours of daylight are there on the summer solstice with the inclination at 45 degrees? To estimate the length of day, identify the time when ...
July 15, 2012

pHYSIC
3. Now wait until the planet is at the summer solstice (to the far left). Here the sunlight arrives perpendicular to the surface. (Note that the fact that the sunlight can be perpendicular to the surface here and parallel to the surface at the winter solstice with the same ...
July 15, 2012

astronomy
2. We ultimately want to find the amount of solar energy that hits the observer on the planet. Energy is usually measured in Joules, but there are other appropriate units of energy as well; kilowatt-hours for example, are used to measure the amount of electrical energy that we...
July 15, 2012

math
The scale factor for two similar triangles is 4 : 3. The perimeter of the smaller triangle is 12. What is the perimeter of the larger triangle
July 5, 2012

math
The scale factor for two similar triangles is 4 : 3. The perimeter of the smaller triangle is 12. What is the perimeter of the larger triangle
July 5, 2012

pre-calculus
Currently in school we're learning about proving identities and for extra credit I got this problem. cosB= -8/17 in quad II and I have to find sin 7B. I have gotten this far: sin7B= sin(3B+4B) sin3Bcos4B+sin4Bcos3B my problem I can't figure out how to further break it ...
May 13, 2012

science
a 110 kg person dives off a cliff and hits the water at 17 m/s. how high is the cliff?
May 4, 2012

Chemistry
When 3.00 g potassium carbonate (K2CO3 ) was mixed with 20.0 mL of hydrochloric acid (HCl, 4.0M) in a calorimeter, the temperature raised 3.0 degrees Celsius. B. Calculate the enthalpy change (H) of the reaction for per mole patassium carbonate. Assume the specific ...
April 15, 2012

health
5-17 years old
April 11, 2012

Math
x^2 + 9x + 20 over x^2 -25 divided by x +4 over x - 4 How to do this really confusing i need to simplify the rational expression
February 25, 2012

geometry
abcd is a rectangle . find the lenght of each diagonal . ac=2(x-3) bd= x+5
February 9, 2012

math
-5a +[2+(3a-7)]
January 17, 2012

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