Chemistry, 24.03.2020 19:58 AgarioEdit

A particular uranium alloy has a density of 18.75 g/cm3. Please answer the following questions below, providing the explanation to your answers. a. What volume is occupied by a critical mass of 49 kg of this alloy? b. The critical mass can be decreased to 16 kg if the alloy is surrounded by a layer of natural uranium (which acts as a neutron reflector). What is the volume of such smaller mass? Compare your answers to the approximate volumes of a baseball, a volleyball, and a basketball.

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Answer from: akbogg3893

a) Critical mass of 49 kg of Uranium: 2600 cm³b) Critical mass of 16 kg Uranium: 850 cm³

Comparison:

Baseball: 221 cm³Basketball: 7,238 cm³Baseball < Critical mass of 16 kg of uranium < critical mass of 49 kg of uranium < basketball.

Explanation:

To find the volumes of the two samples of uranium alloy, you must use the formula of density:

$Density=\dfrac{mass}{volume}\\\\\\Volume=\dfrac{mass}{density}$

a) Critical mass of 49 kg

First, notice that 18.75g/cm³ is the same that 18.75 kg/dm³ (to convert from grams to kg you must divide by 1,000, and to convert from cm³ to dm³ you must divide by 1,000; thus, dividing both numerator an denominator by the same number leaves the fraction unchanged).

Now you can compute:

$Volume=\dfrac{49kg}{18.75kg/dm^3}=2.6dm^3$

You can convert to cm³ multiplying by 1,000cm³/dm³.

Thus, volume = 2,600 cm³.

b) Critical mass = 16 kg

$Volume=\dfrac{16kg}{18.75kg/dm^3}=0.85dm^3$

Volume = 850cm³

Compare with approximate volumes of a baseball, a volleyball, and a basketball:

You can calculate those volumes by using the formula for the volume of a sphere:

$Volume=\dfrac{4}{3}\pi\times radius^3$

For the baseball: radius ≈ 3.75cm

$Volume=\dfrac{4}{3}\pi\times (3.75cm)^3\approx 221cm^3$

For the basketball radius ≈ 12.0 cm

$Volume=\dfrac{4}{3}\pi\times (12.0cm)^3approx 221cm^3\approx 7,238cm^3$

Thus, the comparison of the volumes is:

Baseball < Crittical mass 16 kg of Uranium 16 kg < Critical mass 49 kg of Uranium < Basketball

Answer from: Quest

both adhesion and cohesion are attractions.

they are different in that adhesion is the force of attraction between the molecules of two different substances, whereas cohesion is the force of attraction between molecules of the same substance.

possible examples include capillary action, in which the adhesion between water and glass causes the water to rise in a narrow tube against the force of gravity.

because of hydrogen bonding, water is extremely cohesive.

this causes molecules on the surface of water to be drawn inward, which is why drops of water form beads on smooth surfaces.

hope this .

Answer from: Quest

your answer would be “dry”

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