Methanol ---> Normal BP: 64.6°C --> dHvap: 35.3kJ/mol iso-Propanol ---> Normal BP: 82.3°C --> dHvap: 45.4kJ/mol Cyclohexane ---> Normal BP: 80.7°C --> dHvap: 33.1kJ/mol Question: Ethanol has a normal BP of 78.3°C. Why is the normal BP higher ...
February 13, 2015
The equation for the best fit line was y = -4058.7x + 16.10. Using the equation of the best fit line, calculate the heat of vaporization (delta H) and the NORMAL BOILING POINT (in Celsius) of this volatile liquid. Calculated: dHvap = 33.7kJ/mol ----> I'm really confused...
February 13, 2015
An oxygen molecule consists of two oxygen atoms whose total mass is 5.3 x 10^-26 kg and whose moment of inertia about an axis perpendicular to the line joining the two atoms, midway between them, is 1.9 x 10^-46 kg*m^2. Estimate, from these data, the effective distance between...
February 3, 2015
Q#1-josh just put new tires on his car. if the wheels have a diameter of 14 inches, determine how far will the wheels travel in 3 revolution, to the nearest hundredth? Q#2-Melanie wants to put ribbon around the circumference of a circular section of the park. Ribbon comes in ...
January 18, 2015
A cell is lacking in its supply of amino acids. Which of the following will occur? A- mRNA will not be formed because enzymes may not be present. B- The ribosomes will not work properly because there will be no proteins. C- tRNA may not be able to fulfill its job. D- all of ...
January 1, 2015
Which of the following . is true about the DNA molecule during transcription? A- It opens up all of the way, one gene at a time. B- It unwinds from both ends. C- It makes a copy of itself. D- Only a small area is opened. My choice is C.
December 31, 2014
Which of the following is one role of RNA polymerase during transcription? A- to break down an already existing protein B- to produce a start sequence C- to build a molecule of mRNA D- to switch uracil with thymine on the exposed gene My choice is C.
December 31, 2014
Physics~ ONE MOREE
Thanks soooo much, I always doubt myself when I get really simple looking problems so then I start to over think it too much. At least I now know I should stick with the answer I first get :)
December 29, 2014
Which of the following statements is true? A hypothesis always leads to a theory which leads to a law. A hypothesis always leads to a law which leads to a theory. A hypothesis must lead to a theory only. A hypothesis can lead to either a theory or a law. <<<<<&...
December 29, 2014
noel started going to yoga class on november 3, and went every third day after that. Lana also started classes on november 3, and went every fourth day after that. In how many days will they be in class together again?
December 11, 2014
the cost of a midnight madness movie ticket, is reduced by 2/5 of the original cost, to a cost of 3/5c. which expression is equivalent to the new cost? A)c-3/5c B)1-3/5c C)1-2/5c D)c-2/5c
December 10, 2014
Consider the function y = 3x5 25x3 + 60x + 1. Use the first or second derivative test to test the critical points. How many relative maxima did you find? I got 2 as the relative maxima, is this done correctly?
December 9, 2014
An egg rolls off a kitchen counter and breaks as it hits the floor. The counter is 1.0 m high, the mass of the egg is about 50 g, and the time interval during the collision is about 0.010 s. How large is the impulse that the floor exerts on the egg? use equations of motion to ...
December 7, 2014
An airplane traveling at v = 163 m/s emits a sound of frequency 1730 Hz. At what frequency does a stationary listener hear the sound as the plane approaches? Use 340 m/s for the speed of the sound and answer in Hz.
December 1, 2014
Assume that there is no friction between m2 and the incline, that m2 = 2.4 kg, m1 = 1.2 kg, the radius of the pulley is 0.10 m, the moment of inertia of the pulley is 4.8 kg m2, and θ = 25.0°. a) Find the combined mechanical energy of both masses the instant the ...
November 26, 2014
Elephants communicate via infrasound, at frequencies as low as 14 Hz that can travel up to 10 km. The intensity of these sounds can reach 103 dB, measured a distance of 5.0 m from the source. Determine the intensity level of the infrasound 10 km from the source, assuming the ...
November 24, 2014
Step 1: 5x-6=0 +6 +6 Add the six to both sides Step 2: Then divide the five to both sides isolate the x 5x=6 /5 /5 Answer should be: x=6/5 Then do the same to the second one and you should get x=-25 if you did it right
November 12, 2014
1. A balloonist drops an apple weighing 1.5 N over the side of the balloon's gondola. As it falls and increases speed, the drag force from the air upward on it increases. When the upward force is 0.7 N, what is the direction and magnitude of the net force on the apple? 9.8...
November 7, 2014
1.A plane traveling at 300.0 km/h attempts to land on a 500 m runway. The planes engines and brakes accelerate uniformly at 5.0 m/s2. Will the plane be able to land safely? Show all your work. Include any equations used, the given and unknown. Show all calculations...
October 22, 2014
Find the price of any container of lemonade at a local grocery store. (You can also find prices in advertisements and on the Internet.) Make sure you write down the number of fluid ounces in the container. Determine the unit price and post the information.
September 11, 2014
If a ball is thrown directly upward with a velocity of 14 m/s, its height (in meters) after t seconds is given by y = 14t − 4.9t2. What is the maximum height attained by the ball? (Round to two decimal places.) ______ m After how many seconds is that height attained? (...
August 14, 2014
It says top of the ball, so you need to minus both of the heights by 8cm. h1 = 0.8 -0.08 = 0.72 It is given that kinetic energy before striking the surface is 0.75 J. So you just nid to use potential energy formula(mgh) to calculate the mass of the ball . h2 = 0.45 - 0.08 = 0....
May 31, 2014
Two kids are building a rocket for science class. once the rocket is launched its height in feet, h(t) can be found using the function h(t)=-16t^2+128t where t represents time in seconds. They record the time from the moment the rocket launches until it falls to the ground. (...
April 17, 2014
Help please? 1)A sample of propane gas occupies 625 cm3 at 20.0 °C and 750 torr. What is the final volume in cubic centimeters at -80.0 °C and 750 torr? 2)If oxygen gas is collected over water at 25 °C and 775 torr, what is the partial pressure of the O2? The vapor...
April 16, 2014
An infinitely long thin metal strip of width w=12cm carries a current of I=10A that is uniformly distributed across its cross section. What is the magnetic field at point P a distance a=3cm above the center of the strip as shown? This one requires some integration! I suggest ...
April 7, 2014
Nikki made 2 gallons of punch with fruit juice and ginger ale. The recipe requires 1 gallons of ginger ale. What percent of the total recipe is fruit juice? A- 50% B- 33 1/3% C- 25% D- 10% I got 50% because u need 1/2 more but the answer is 25 please explain
March 22, 2014
The Achilles tendon is attached to the rear of the foot as shown in (Figure 1) . A person elevates himself just barely off the floor on the "ball of one foot." Assume the person has a mass of 80kg and D is twice as long as d.Find the tension FT in the Achilles tendon...
February 17, 2014
a kitchen is shaped like a rectangle with dimensions of 11 1/2 ft. by 9 1/2 ft. the floor of the room is made of square tiles with a side length of 1.2 ft. What is the number of tiles that will cover the kitchen floor?
February 9, 2014
A boat can go 20 miles against a current in the same times that it can go 60 miles with the current. The current is 4 miles per hour. Find the speed of the boat with no current.
January 15, 2014
hydrogen gas can be produced by reacting aluminum with sulfuric acid .How many L hydrogen gas are produced by reacting 15.0 mol of sulfuric acid with 15.0 mol of aluminum at STP?
May 19, 2013
When 306 stamps were shared among Pat, Kyle, and Ryan, Pat got twice as many stamps as what Kyle and Ryan got together. If Kyle got 18 stamps more than Ryan, how many stamps did Ryan get? Don't forget to show your work.
March 25, 2013
A bookshop had 60 boxes of pencils. Each box contained 85 pencils. Half of the pencils were packed into packets of 25 pencils and the rest were packed into packets of 20. How many packets of pencils were there altogether? My answer is 229 am i right? How many pencils were left...
March 18, 2013
mass of the metal 7.26g volume of water in the calorimeter 10mL initial temp of water in calorimeter 21.5 degrees C initial temp of metal 95.5 d C final temp in mixture in calorimeter 23.8 D C question: calculate the energy lost by the metal taking into consideration that it ...
February 28, 2013
Silicon carbide is one of the hardest materials known. It is often known commercially as carborundum. Silicon carbide is used primarily as an abrasive for sandpaper and is manufactured by heating common sand (silicon dioxide, SiO2) with carbon. - What mass of SiC should result...
February 10, 2013
2KI+Pb(NO3)2=2KNO3+PbI2 suppose a solution containing 1.25g of KI is combined with a solution containing 2.42g Pb(NO3)2 _what mass of the yellow PbI would result what is the limiting reactant How much in grams of the excess reactant was used how much in grams of the excess ...
February 10, 2013
A fruit seller has an equal number of apples and oranges.He sold 109 oranges and 45 apples.The number of apples left is 5 times the number of oranges left.What is the total number of fruit he had at first?
February 4, 2013
A fruit seller has an equal number of apples and oranges. He sold 109 oranges and 45 apples.The number of apples left is 5 times the number of oranges left. What is the total number of fruit he had first?
February 3, 2013