Iridium-192 is used in cancer treatment, a small cylindrical piece of 192 Ir, 0.6 mm in diameter (0.3mm radius) and 3.5 mm long, is surgically inserted into the tumor. if the density of iridium is 22.42 g/cm3, how many iridium atoms are present in the sample?
Let us start by computing for the volume of the cylinder. V = π(r^2)*h where r and h are the radius and height of the cylinder, respectively. Let's convert all given dimensions to cm first. Radius = 0.03 cm, height is 0.35cm long.
V = π * (0.03cm)^2 * 0.35 cm = 9.896*10^-4 cm^3
Now we have the volume of 192-Ir, let's use the density provided to get it's mass, and once we have the mass let's use the molar mass to get the amount of moles. After getting the amount of moles, we use Avogadro's number to convert moles into number of atoms. See the calculation below and see if all units "cancel":
9.896*10^-4 cm^3 * (22.42 g/cm3) * (1 mole / 191.963 g) * (6.022x10^23 atoms /mole)
= 6.96 x 10^19 atoms of Ir-122 are present.
The origins of the word fossil are French and Latin
Answer:
A
Explanation:
Acetals are geminal-diether derivatives of aldehydes or ketones, formed by reaction with two equivalents (or an excess amount) of an alcohol and elimination of water. Ketone derivatives of this kind were once called ketals, but modern usage has dropped that term.
To achieve effective hemiacetal or acetal formation, two additional features must be implemented. First, an acid catalyst must be used because alcohol is a weak nucleophile and second the water produced with the acetal must be removed from the reaction.
Main sequence stars with low temperatures tend to have low luminosity is based on Hertzprung-Russell diagram
<h3>What is the Hertzsprung-Russell diagram's main sequence?</h3>
The bright, hot stars in the image's upper left are the main sequence group, which stretches roughly diagonally to the lower right (dim and cool). In the bottom left are white dwarfs, which are small, faint, and hot. In the top right are giant and supergiant stars, which are big, bright, and cool.
<h3>What is the main sequence star H-R diagram trend?</h3>
Main sequence stars have a wide range of effective temperatures, but because they are brighter at higher temperatures, they normally follow a band from the bottom right to the top left of the diagram. Inside the cores, hydrogen and helium are fusing together.
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<span>The theory of global warming states that the average temperature of the earth has been increasing over time. This theory will be most strongly affected by </span><span>scientific studies that </span><span>reveal how the earth's temperature has fluctuated in the past.</span>
