Answer:
Density is a measure of mass per unit of volume. Density is a measure of mass per volume. The average density of an object equals its total mass divided by its total volume.
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Global winds, coriolis effect and <span>continental deflections. Hope this helps!</span>
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:
4.50 L
Explanation:
First we <u>calculate how many moles are there in 3.84 L of a 8.50 mol/L solution</u>:
- 3.84 L * 8.50 mol/L = 32.64 mol
Now, keeping in mind that
- Concentration = Mol / Volume
we can calculate the volume of a 7.25 mol/L solution that would contain 32.64 moles:
- Volume = Mol / Concentration
- Volume = 32.64 mol ÷ 7.25 mol/L
So we could take 4.50 L of the 7.25 mol/L solution and evaporate the solvent until only 3.84 L remain.