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.
If pH+ is 7
It is Neutral solution
There are two terms
a) accuracy : it relates to the exactness of an answer that how an answer is close to the actual answer or actual reading
So 104.6 is accurate
b) Precision : This is related to the closeness of different readings with each other
The first reading is 103.7 and the second one is 108.4 so the second reading is quite different from the first reading so it cannot be called as precised
Again 105.8 has good difference from the second reading hence again this is not precised
However the last reading 104.6 is quite near to 105.8 so 104.6 can be called as precise
Answer:
Atomic Mass: 78.96 amu. Melting Point: 217.0 °C (490.15 K, 422.6 °F) Boiling Point: 684.9 °C (958.05005 K, 1264.8201 °F) Number of Protons/Electrons: 34 ... [Bohr Model of Selenium] ... im sorry hope this helped
Explanation:
An open system<span> is a system that has external interactions.</span>
