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.
Answer:
A) litmus is red
Explanation:
To answer this question, it can be helpful to have the color charts. Litmus, phenolphthalein and methyl orange are ways to test the pH of a substance.
<u>Litmus paper</u>
Litmus can tell you if a substance is an acid or a base. You need to put the substance on both red litmus and blue litmus paper.
pH < 7: both papers are red. 3.0 is less than 7.
pH = 7: none of them change color
pH > 7: both papers are blue
<u>Phenolphthalein</u>
When this indicator is added to a substance, the result is either colorless or pink.
0 < pH ≤ 7: colorless. The color is not red or blue for pH 3.0.
pH > 7: pink
<u>Methyl orange</u>
0 < pH < 4: red. The color is not yellow if the pH is 3.0.
4 ≤ pH < 5: orange
pH ≥ 5: yellow
Answer:
Cu+(aq)--->Cu2+(aq) + e- : oxidation
reason: there is loss of electrons.
I2(s) + 2e--->2I-(aq) : reduction
reason: There is reduction of electrons.
Answer:
c ) 29.4 psi
Explanation:
If the density of earth was twice than its actual density which is 5.51 g/mL, then at sea level the atmospheric pressure of earth in British units would be equal to 29.4 psi because increase of gravity, increase occurs in the atmospheric pressure. If we double the gravity of earth by double of the earth density, so the weight of that same mass of air will be double which leads to the doubling of the atmospheric pressure at the sea level.
