M. Why does the color of a liquid get lighter as it is diluted? What causes this
ID: 851096 • Letter: M
Question
M. Why does the color of a liquid get lighter as it is diluted? What causes this to happen? N. Water boils at a lower temperature at higher altitude, but would you expect it to reach boiling temperature faster at sea level or at 9500 feet elevation in Colorado? Assume that in both cases, the pot of water is uncovered and an identical heating device is used. In this lab, you took warm and cold temperature measurements using an alcohol thermometer. Only a few decades ago, mercury thermometers were a standard feature of every chemistry laboratory. Mercury's toxic properties have long been understood. For example, Romans used mercury mines as prisons (poisoning took care of the need to dispose of miscreants) and 19th century hat maker's shaky and drunk-like behavior (hat makers used mercury during the felting process) inspired the "Mad Hatter" in "Alice in Wonderland." It wasn't until the 1970s that mercury began to be eliminated from all medical equipment. Mercury was used in thermometers for its unique expansion and contraction properties. The bulk of it sits in the bulb and rises up the thinner cylinder as the temperature changes. Suppose a mercury thermometer contains 4.521 grams of mercury and has a capillary cylinder that is 0.250 mm in diameter. What distance (in mm) does the mercury rise in the cylinder when the temperature changes from 25 degree C to 50 degree C? The density of the mercury at these temperatures is 13.534 g/cm3 and 13.472 g/cm3 respectively. How many atoms of mercury are found in this particular thermometer? P. In the movie, Raiders Of the Lost Ark, Indiana Jones replaces a golden statue with a similar sized bag of sand on a weight bearing alarm. If the alarm is tripped, he will find himself in a life threatening booby trap. If not, the gold statue is his. For fun, lets assume the statue is in the shape of a gold cylinder and the sand is in a can. It so happens that the can of sand and the gold cylinder are exactly the same dimensions (length = 21 cm and radius = 4.1 cm) What is the mass of each cylinder? Ignore the mass of the can itself and show your calculations. (Density of gold = 19.3 g/cm3, density of sand = 3.00 g/cm3) Will weighted alarm trip? Please explainExplanation / Answer
M.
As the liquid is diluted, the molecules move farther apart from each other. Due to this, they are no more concentrated in a small place but are rather spread out over a larger volume due to dilution. As a result, the concentration of color starts decreasing and it gets lighter.
The molecules move apart due to the phenomena of diffusion, causing them to move from high concentration to low concentration areas.
N.
Elevation is measured with respect to sea level, so at an elevation of 9500 feet in colorado, the altitude is higher as compared to sea level. Thus, water will reach its boiling point faster at the 9500 feet elevation in Colorado as compared to at the sea level
O.
1)
Distance by which mercury rises = Final height-Initial height = Hf-Hi
Final height, Hf = Final volume/Cross sectional area
Final volume = density at 50 'C/mass = 4.521/13.472 = 0.335 cm3
Given : Radius,r = 0.250/2 mm = 0.125 mm = 0.0125 cm
So, A = pi*r2 = pi*0.01252 = 4.908*10-4 cm2
Thus, Hf = 0.335/(4.908*10-4) = 682.56 cm
Similarly, Hi = Initial volume/A = (4.521/13.534)/(4.908*10-4) = 680.61 cm
Thus, height by which mercury rises = Hf-Hi = 682.56-680.61 = 1.95 cm = 19.5 mm
2) Atoms of mercury = moles of mercury*Avogadro's number
Moles of mercury = mass present/molecular mass = 4.521/200.6 = 0.02253
Avogadro's number = 6.02*1023
So, atoms of mercury present = 0.02253*6.02*1023 = 1.356*1022 atoms
P.
Volume of cylinder = pi*r2*h
Given : h = 21 cm, r = 4.1 cm , so volume = pi*4.12*21 = 1109.01 cm3
(a)
Mass of gold cylinder = density of gold*volume of cylinder = 19.3*1109.01 = 21403.893 g
Mass of sand cylinder = density of sand*volume of cylinder = 3*1109.01 = 3327.03 g
(b)
Yes, the alarm will trip, because the weight of the two cylinder are different
Weight of gold cylinder is much higher ( about 7 times ) than that of sand cylinder. This will cause the alarm to trip.
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