Answer:
this option is correct the amount of heat required to turn a mole of a solid into a liquid
Answer:
Explanation:
Ca(In)²⁺ + EDTA → Ca(EDTA)²⁺ + In
We use the volume of EDTA consumed in the titration to <u>calculate the moles of Ca⁺² ions</u>:
- 0.012 L * 0.0600 M *
= 7.20x10⁻⁴ mol Ca⁺²
Now we <u>calculate the molarity</u>:
- 7.20x10⁻⁴ mol Ca⁺² / 0.050 L = 0.0144 M
To calculate in ppm, we <u>use the moles of Ca⁺² and convert to mg of CaCO₃:</u>
- 7.20x10⁻⁴ mol Ca⁺² = 7.20x10⁻⁴ mol CaCO₃
- 7.20x10⁻⁴ mol CaCO₃ * 100g/mol *
= 72 mg CaCO₃
Finally, <u>the concentration in ppm</u> is:
- 72 mg CaCO₃ / 0.050L = 1440 ppm
Yes I think & I Belive it moves across the surface
Answer:
Molar heat of solution of KBr is 20.0kJ/mol
Explanation:
Molar heat of solution is defined as the energy released (negative) or absorbed (Positive) per mole of solute being dissolved in solvent.
The dissolution of KBr is:
KBr → K⁺ + Br⁻
In the calorimeter, the temperature decreases 0.370K, that means the solution absorbes energy in this process. The energy is:
q = 1.36kJK⁻¹ × 0.370K
q = 0.5032kJ
Moles of KBr in 3.00g are:
3.00g × (1mol / 119g) = 0.0252moles
Thus, molar heat of solution of KBr is:
0.5032kJ / 0.0252moles = <em>20.0kJ/mol</em>
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.
