<span>He should use a scale and record the weight in N. The beaker is used for liquid measurement and the scale is used for measuring sold things. A dumbbell is not a liquid material that is why the need of the scale will give it the accurate measurement that Hunter wants to know.</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.
The amount of matter in an object is consisted to be MASS .
Mass of water : 0.45 g
<h3>Further explanation</h3>
Given
1.5 g ethanoic acid
Required
Mass of water
Solution
Reaction
<em>CH₃COOH + NaOH ⇒H₂O + CH₃COONa</em>
mol CH₃COOH(MW=60 g/mol) :
= mass : MW
= 1.5 : 60
= 0.025
mol H₂O from the equation :
= 0.025(mol ratio CH₃COOH : H₂O= 1 : 1)
Mass of water :
= mol x MW water
= 0.025 x 18 g/mol
= 0.45 g
