The enthalpy of vaporization of H2O is higher than the enthalpy of fusion of H2O, therefore vaporizing the same mass of H2O would require more heat/energy than melting the same mass of H2O.
Answer:
Temperature
Explanation:
Kinetic energy of gass molecules is directly propotional to the temperature.
Answer: the density of the solid metal is 22.5176 g/cm
Explanation:
Given that;
mass of solid metal = 255 g
the cylinder and its contents weigh 101g less than before
also given that density of mercury = 13.6 g/cm³
Volume of the solid metal = volume of mercury which was absent in the first weighing
so let volume = Vcm³
Mass of mercury which was absent in the first weighing = density × volume
= 13.6 g/cm³ × Vcm³ = 13.6V g
now since the cylinder and its contents weigh 101g less than before,
it means the difference in mass between the solid and metal and the mass of mercury is equal to 101 g
so
255 - 13.6V g = 101g
13.6V g = 255 g - 101 g
13.6V = 154
V = 154 / 13.6
V = 11.3245 cm³
Now Density of solid metal will be;
⇒ mass / volume
= 255 / 11.3245
= 22.5176 g/cm
Therefore, the density of the solid metal is 22.5176 g/cm
Mechanical and gravitational potential energy
Answer:
Explanation:
The<em> half-life </em>time of a radiactive isotope (radioisotope) is a constant value, meaning that the amount of the radioisotope that decays will be (1/2) raised to the number of half-lives passed.
Naming A₀ the initial amount to the radioisotope, you can build this table to find the amount left.
Number of half-lives amount of radiosotope left
0 A₀
1 (1/2) × A₀
2 (1/2)×(1/2)×A₀ = (1/2)² × A₀
3 (1/2)³ ×A ₀
4 (1/2)⁴ × A₀
n (1/2)ⁿ × A₀
Now calculate the number of half-lives the strontium-90 sample has passed after 100 years:
- n = 100 years / 28.1 years ≈ 3.5587
Hence, the amount of strontium-90 is:
In percent, that is:
Rounding to two significant figures, that is 8.5%.
<u>Conclusion</u>: <em>The percent of strontium-90 left after 100 yeaers is 8.5% </em>(choice number 4).
