D! the molecules of the warmer water would have a higher average kinetic energy :)
What mass of the following chemicals is needed to make the solutions indicated?
Answer:
271.6g
Explanation:
The mass of the chemicals need to make the needed solution can be derived by obtaining the number of moles first.
Given parameters:
Volume of solution = 1L
Molarity of HgCl₂ = 1M
number of moles of HgCl₂ = molarity of solution x volume
= 1 x 1
= 1 mole
From;
Mass of a substance = number of moles x molar mass;
we can find mass;
Molar mass of HgCl₂ = 200.6 + 2(35.5) = 271.6g/mol
Mass of the substance = 1 x 271.6 = 271.6g
The boiling point of oxygen is higher than nitrogen's boiling
The reason the boiling point of O2 is higher is not because of increased van der Waals interactions, but simple physics. The mass of a molecule of O2 is greater than that of a molecule of N2, so the molecule of O2 traveling at a speed sufficient to break out of the liquid phase has a greater kinetic energy than an analogous N2 molecule.
The net effect is that more energy must be distributed throughout a sample of O2 to achieve a given vapor pressure (in this case equal to atmospheric pressure) than for a sample of N2. More energy means greater temperature.
According to half life equation:
T(1/2) = ㏑2 / K1
when the T(1/2) = 4 min * 60 = 240 sec
by substitution:
240 = 0.6931 / K1
K1 = 2.9 x 10^-3
when the second T(1/2) = 20 sec, so to get K2:
T(1/2) = 0.6931 / K2
by substitution:
20 = 0.6931 / K2
∴K2 = 3.4 x 10^-2
so, we can get T2 by using this formula:
㏑ (K2/K1) = Ea/R (1/T1 - 1/T2)
by substitution:
㏑(3.4 x 10^-2)/(2.9 x 10^-3) = (24520 / 8.314) (1/298 - 1/T2)
∴ T2 = 396.7 K
= 396.7 - 273 = 123.7 °C
