Saturday
May 23, 2015

Posts by Zach


Total # Posts: 335

Chemistry
How would I calculate the heat of solution in Joules for dissolving 0.1 mole of NH4NO3 in 100 mL of water? The initial temperature was 22.8 degrees celsius and the temperature after the salt dissolved was 18.1 degrees celsius.
July 24, 2012

Chemistry
Oh ok and I used a device called a Xplorer GLX and it measured the pressure of the flask before I put in the magnesium and hydrochloric acid and then it measured the pressure once the reaction was complete. But thank you for all of your help!
July 15, 2012

Chemistry
In the lab I had a strip of magnesium that weighed 0.029 grams and I added 15 milliliters of 0.5 M hydrochloric acid into a flask and I never used any water during the lab. So I don't really understand where I would get the water vapor pressure.
July 15, 2012

Chemistry
The reaction for my lab is Mg(s)+2HCl(aq)--> MgCl2(aq)+H2(g) I need to find the pressure of the hydrogen gas. Initial Pressure = 0.98692 atm Total Pressure = 1.64816 atm I don't know if I calculated the pressure of hydrogen gas correctly. I used the formula Total ...
July 15, 2012

Chemistry
What is the balanced equation for copper (II) sulfate pentahydrate and potassium oxalate monohydrate?
July 6, 2012

Chemistry
How would I figure out what is produced during a chemical reaction between 0.5 grams of sodium bicarbonate and 3 grams of citric acid? I know that it produces carbon dioxide and water but my professor said I am missing something from my equation.
June 26, 2012

Physics
Microwaves are electromagnetic waves transmitted at a normal frequency of 2.45 GHz. Find the wavelength of the microwaves.
May 29, 2012

physics
What is the index of refraction of a liquid in which the speed of light is 2.22 x 108 m/s?
May 14, 2012

Geometry
If you stand at stree level, the angle of elevation to a buildings tenth-story window is great than the angle of elevation to one of its ninth-story windows.
April 24, 2012

Physics
A certain dog whistle operates at 23.5 kHz, while another (brand X) operates at an unknown frequency. If neither whistle can be heard by humans when played separately, but a shrill whine of frequency 9200 Hz occurs when they are played simultaneously, estimate the operating ...
April 23, 2012

Algebra
A ball is thrown up with an initial velocity of 32 feet per second. How many seconds will it take for the ball to return to the ground using the formula h=vt-16t^2?
March 25, 2012

Physics
Block M (mass of 15.65 kg) is initially moving to the left with a speed of 3.77 m/s. The mass of m is 8.26 kg and the coefficients of friction are Us = 0.411 and Uk = 0.304. The string is massless and the pulley is massless and frictionless. How fast will M be traveling when m...
March 1, 2012

physics
A block of mass M = 6.755 kg is pulled along a horizontal frictionless surface by a rope of mass m = 0.592 kg, as shown in Fig. 5-63. A horizontal force = 41.5 N is applied to one end of the rope. Assume that the rope only sags a negligible amount. Find (a) the acceleration of...
February 26, 2012

MATH
THE RATIO OF THE PERIMETERS OF TWO SIMILAR TRIANGLES IS 1:3. htE AREA OF THE LARGER TRIANGLE IS 27FT^2. WHAT IS THE AREA OF THE SMALLER TRIANGLE. SORRY FOR THE CAPITAL LOCK. MY COMPUTER KEPBOARD WILL NOT PUT IT TO LOWER CASE SORRY AGAIN.
February 21, 2012

math
The perimeter of rectangle ABCD is 256 inches. It's length is 3 times as long as its width. Find the area of triangle ABC.
February 14, 2012

Physics
A hydraulic jack is designed so that when the handle is pushed down 1 m, the piston raising the load moves up 0.015 m. IMA= 66.67 AMA= 26.67 Efficiency= 40% At this efficiency, what is the force required to lift a 5000 N weight?
February 9, 2012

physics
When a 1150 kg space rocket lifts off of ground. How many joules of energy has been provided by its engine during the time in which it achieves a speed of 180 m/s.
February 7, 2012

physics
use s=ut + 0.5*a*t^2 in vertical direction s =0 because there is no vertical displacement at the time it reaches the ground a= -9.81 ; minus because we consider up as the positive direction. u= 24.8 sin 62.5 ; vertical component of the Velocity SO t= 2*u/ -a = (2*24.8 sin 62.5...
January 29, 2012

chemistry
yes I mean Fe2(SO4)3. How come you only used TWO of the reactants for your equation?? What happens with the third one?
January 24, 2012

chemistry
What products are formed when aqueous solutions of Na2SO4, Fe3SO42, and BaCl2 are mixed together ? Can someone help me write out a balanced equation for the reaction that occurs.
January 24, 2012

Physics
A rock (m = 1.5 kg) moving at 4.2 m/s north collides with a ball (m = 0.061 kg) that is initially at rest. What is the velocity of the rock after the collision if the velocity of the ball after the collision was 8.4 m/s north?
January 15, 2012

Math (algebra)
Matt has to bake muffins. He uses x eggs for each 200 grams of flour. If he has to use 900 grams of flour how many eggs will he use? I have to set this up as an algebra problem. I am stuck. Our class is just learning this and I dont understand.
January 11, 2012

Civics
I have a civics final tomorrw. the question I'm working on is "To Postpone Sentence/Fine" It is a crossword puzzle and the first letter is R - - - I - - - . the book says to suspend, but I can't fine any word that starts with R? Please help.
January 10, 2012

vocabulary
Thank you for the link.. I used Gloom is the prevailing mood after we lost the basketball game.
January 10, 2012

vocabulary
How do I use the word prevailing in a sentence?
January 10, 2012

Physics
A 34-g bullet traveling at 120m/s embeds itself in a wooden block on a smooth surface. The block then slides toward a spring and collides with it. The block compresses the spring (k=100 N/m) a maximum of 1.25 cm. Calculate the mass of the block of wood.
January 5, 2012

Physics
A 200 g mass is attached to a spring of spring constant k. The spring is compressed 15 cm from its equilibrium value. When released the mass reaches a speed of 5 m/s. What is the spring constant (in N/m)?
January 5, 2012

Physics
A ball bounces upward from the ground with a speed of 14 m/s and hits a wall with a speed of 12 m/s. How high above the ground does the ball hit the wall? Ignore air resistance.
January 5, 2012

Chemistry
A(n) ____ reaction is one in which oxygen reacts with another compound to form carbon dioxide, water, and heat.
January 4, 2012

french
I am supposed to choose from pronom indirect (indirect pronouns), and pronom disjoint (stressed pronuons). Naturally, if you had an answer for the question, you'd know what those meant, but I just thought I should give a better idea of my level of understanding... Anyway, ...
December 18, 2011

8th Grade
301 m
December 5, 2011

Physics
A 10-g bullet is shot vertically into a stationary 8-kg block. The block lifts upward 3.0 mm. The bullet penetrates the block in a time of .001 seconds. Assume the force exerted on the block is constant. What is the impulse imparted on the block by the bullet?
November 30, 2011

Algebra II
The intensity of illumination at a given point is directly proportional to the intensity of the light source and inversely proportional to the square of the distance from the light source. If a desk is properly illuminated by a 74.0 w lamp 8.00 ft from the desk, what size lamp...
November 21, 2011

Algebra II
The volume of a given weight of gas varies directly as its absolute temperature t and inversely as its pressure p. If the volume is 4.45 m^3 when p=225 kilo pascals (kpa) and t = 305 K, find the volumn when p = 325 kpa and t = 354 k.
November 21, 2011

Algebra II
The amount paid to a work crew varies jointly as the number of persons working and the length of time worked. If 5 workers earn $5123.73 in 3.0 weeks, in how many weeks will 6 workers earn a total of $6148.48?
November 21, 2011

english
In the sentence: Not only it does affect women and children, but it also affects our society and our future generations. is the sentence correct? Thank you :)
November 17, 2011

physics
how much force is exerted on a bag that is lifted at 5m/s^2 with 18.5kg in it
November 15, 2011

Math
What is 5x^2y^-3 over 25x^6y^2 in simplest form
November 13, 2011

Math
What is the annual interest rate if $1600 is invested for 6yrs. and 456 in intrest is earned
November 9, 2011

science
the lack of atmosphere.
November 8, 2011

science
the tracks of the astronauts who landed on the moon are still there in the dust and show no signs of being worn away.this is attruted to the lack of atmosphere on the moon. which of the following best accounts for the lack of atmosphere.
November 8, 2011

physics
A 4.85-kg block is placed on top of a 12.0-kg block that rests on a frictionless table. The coefficient of static friction between the two blocks is 0.645. What is the maximum horizontal force that can be applied before the 4.85-kg block begins to slip relative to the 12.0-kg ...
November 7, 2011

Physics
A.) h/4μk B.) h/16μk
November 1, 2011

Chemistry
"Suppose some sort of clamp is applied to hold an electron fixed at the distance of 2.5 Angstroms from a lithium nucleus Li3+ which is also clamped into position. Calculate the magnitude of the force between the two fixed particles." The books says the answer is: -2....
October 17, 2011

algebra 1
or 100%, depending on what your teacher is looking for
October 16, 2011

Chemistry
"Suppose some sort of clamp is applied to hold an electron fixed at the distance of 2.5 Angstroms from a lithium nucleus Li3+ which is also clamped into position. Calculate the magnitude of the force between the two fixed particles." The books says the answer is: -2....
October 16, 2011

Business Managment
I need help answering these questions
October 14, 2011

Physics
a) Vi= 6.7sin(53) Vi = 5.35 V = Vi - gt at top 0 = Vi - g t so t at top = Vi/g t = .55 y at top = 1 + Vi t - 4.9 t^2 = 1 + 5.35(0.55) - 4.9(.55)^2 y at top = 2.46 b) u = 6.7 cos 53 x = u t x = (6.7 cos 53)(.55) x = 2.22
October 5, 2011

Simple Subjects
What is the complete and simple subject for, One story links this day to an old Roman festival?
October 4, 2011

geometry
Given three collinear points X, Y, and Z and XY=8 and YZ=20, what is the length of a segment joining the midpoint XY and YZ?
September 24, 2011

Physics
A ball swings in a vertical circle at the end of a rope 1.50 m long. When the ball is 35.9° past the lowest point on its way up, its total acceleration is (-22.5 i + 20.2 j)m/s^2. Find radial acceleration?
September 17, 2011

MAth (make equation true)
5+5*6/2=24
September 14, 2011

Math
your aunt gives you a check on your birthday each year. on your first birthday , she gives you a check for one cent. the next year she gives you 3 cents , then 9. each year she triples the amount of the previous year 's check. how old will you be when she gives you a check...
September 11, 2011

geometry
Given the points K=(-2,1) and m(3,4), find coordinates for a point J that makes angle JKM a right angle.
September 8, 2011

Calculus Precalculus
Answer the calculus question about Point P, 45 mph, etc. It is ALREADY posted on here.
August 27, 2011

math
write an equation to show the relationship between the score received and the number of questions the students answers correctly
August 25, 2011

Calculus
Hey, how come no one has answered parts c through e? I need some help here!!! This is the ONLY site on the internet that has this problem worked.
August 24, 2011

chemistry
If 1/2 moles of 02 react with 24 moles of hydrogen, can 2 moles of water be produced?
June 15, 2011

Chemistry
A gas at 1.5 atm, 2.3L, and 23degreeC changed to 1.0 atu and 2.8L. What is the new temperature?
May 21, 2011

Chemistry
Calculate the mass of NaCl produced when 5.50 moles of Sodium reacts with excess chlorine gas.
May 21, 2011

chemistry
and List all measurements and include proper labels. Molecular weight of benzoic acid: 122.12 g/mole Mass of benzoic acid used: Titration of NaOH and benzoic acid: (Fine Titrations Only) Trial 1 Trial 2 Initial volume(NaOH)(ml) final volume(NaOH)(ml) Calculations/...
April 15, 2011

chemistry
PLEASE NOTE: Titration requires several steps in order to obtain exact results. The procedures described in this lab assume that you have already done the TITRATION TUTORIAL and are familiar with the technique. 1. Prepare the NaOH solution by dissolving approximately 4g of ...
April 15, 2011

math- algebra- help please!
3 dice are rolled let (y,r,b) represent each outcome? a- sample space b- prob rolling a sum of 18 c- prob of rolling a sum less than 5
April 6, 2011

Spanish
A usted _______gusta jugar a los deportes. What goes in the blank?
March 29, 2011

Calculus
The Problem: The spherical top holds a little over 54,000 gallons of water. The base of the top is 60 feet above the ground. The diameter of the supporting column is one-third the radius of the sphere. The base of the supporting column flares out like a cone (a frustum) so ...
March 27, 2011

physics
A certain roller coaster has a circular, vertical loop of radius 10 meters, such that at its top the riders are upside down. How fast does the roller coaster move at this point if the riders feel perfectly weightless when passing the top of the loop?
March 20, 2011

math
how do i write a decimal and a fraction to show what part of a dollar one penny represents
March 2, 2011

algebra2/trig
4.8 hours
February 26, 2011

Algbra
I need help with the following question. Solve for y: 3x - 2y = 8 + x Please show the steps and the answer, thanks.
February 14, 2011

Geometry
find the lengths of the sides of a triangle whose perimeter is 37. The measure of the first side of the triangle is 8 less than the second side, and the second side is twice the length of the third side
February 10, 2011

Algebra
Please help me solve for the following coefficients. The equation is: 2X-Y=4 if X = 0, then Y = ? if Y = 0, then X = ? if X = 1, then y = ? if Y = -6, then X =? Thanks!
February 9, 2011

physics
Approximate the gravitational force of attraction between a 49.0 kg girl and a 52.0 kg boy if they are sitting 2.5 m apart
February 7, 2011

Algebra 2
A Rectangular Field is to be enclosed by a fence and divided into three parts by another fencer. Find the maximum area that can be enclosed and separated in this way with 500 meters of fencing.
February 3, 2011

Algbra
I need help with the following problem. -6 less than or equal to 3 + 1/3a less than or equal to 5 Please show steps and answer. Thanks.
February 2, 2011

Physic
A ball throw at 45 degree angle with an initial speed of 15m/s. the time for the ball to reach its highest point can be found from the data and known constants using which equation? solve for time?
January 31, 2011

college calc
vertical asymptotes of tan(pi*x)
January 30, 2011

Algbra
1/4x - 5/12x = x - 4/3 Please show steps and answer. Thanks.
January 24, 2011

math
If g(x)= -2^2 and h(x)=x-2/5. Find the indicated value. h(g(5)) I got -5.4. is that right?
January 24, 2011

chemistry
How many grams are in one milliliter?
January 23, 2011

math
(y^4)^1/6
January 20, 2011

chemistry
your carbon atoms aren't equal and i didn't split up my carbon dioxides however it should change anything balancing wise. 2C3H6N6O6 + 3O2==> 6h20 +6CO2(or 3CO2 +3CO2) + 6N2 C=6 C=6 H=12 H=12 N=12 N=12 O=18 O=18 Hope this helps!
January 17, 2011

Algbra
How do you solve this problem? 3/5k - (k + 1/3) = 1/15 (k + 3) Please show me the steps. Thanks.
January 16, 2011

chemistry
In my book the anser for D is 2.68 x 10^4 mg/L as CaCO3, my first thought was to do what you did but i cant get to the answer in the book, am I missing something very obvious here? Im getting like 5.4 x 10^4
January 15, 2011

math
4(3)+4(3) *4 *4 --------- 12+12=24
January 12, 2011

physics
A museum curator moves artifacts into place on many different display surfaces. Use the values in Table 4-2 in the textbook to find Fs,max and Fk if you were to move a 157 kg aluminum sculpture across a horizontal steel platform. Fs,max: Fk:
November 18, 2010

Math
Are (1/2 x 3) x 8 and 3 x (1/2 x 8) equal? Explain how this can help in finding the area of a triangle
November 17, 2010

math
I need to variables would equal 180 by being divided by 1/2
November 17, 2010

math
A=1/2bh A= 1/2 ? ? A= 180 what could the base and height be?
November 17, 2010

math
How does (1/2 x 3) x 8 and 3 x (1/2 x 8) being equal help in finding the area of a triangle?
November 17, 2010

math
Finding the area or a triangle A=1/2bh A= 1/2 x 13.6 x 7
November 17, 2010

math
How do I find the area of a triangle?
November 17, 2010

Chemistry
calculate the number of formula units of 0.0067 g of lithium carbonate, Li2CO3?
November 11, 2010

Chemistry
How many grams of potassium can be obtained from the decompostion of 100 grams of KCl?
November 11, 2010

chemistry
How much iron can be recovered from 25.0 grams of FeO?
November 11, 2010

science
In order for conduction to occur particles must make what?
October 26, 2010

algebra
86 degrees Fahrenheit = 30 degrees Celsius so, (30,86)
October 13, 2010

Physics
I have one problem I just can't figure out, A machine in an ice factory is capable of exerting 3.30 * 10^2 N of force to pull large blocks of ice up a slope. The blocks each weight 1.21 * 10^4th N. Assuming there is no friction, what is the max angle that the slope can ...
October 13, 2010

physics
A. 5.729 m/s^2 B. 51.5625 m/s^2 C. 183.333m D. 70,088m
October 13, 2010

physics
A. a = v/t 165km / 8s = 20.625 km/h/s B. t= 60s-8s =52s, V= 1650km/h-165km/h =1485km/h a=v/t 1485km/h / 8s= 185.625km/h/s C. d=1/2at^2 1/2 * 20.625 km/h/s * (8s)^2 = 183.333m D. 60s-8s=52s d=1/2at^2 1/2 * 186.625km/h/s * (52s)^2 = 70.088km
October 13, 2010

analogies
dollar:cent;meter:centimeter
October 6, 2010

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