A light layer of vacuum grease is applied to the rim of the belljar. Water at room temperature is placed inside and the vacuum pump is then used to evacuate the vessel. When the air pressure is reduced to the vapour pressure of water at room temperature the water will begin to boil.
Answer:
7430.5 Joules (7.4*10^4 Joules)
Explanation:
Q=mc∆T
where Q is energy in Joules.
Now m=250 g
c= 0.386 J/g°C
∆T = 99 - 22 = 77 °C
plugging the values in gives
Q=250*0.386*77=7430.5 Joules
(7.4*10^4 Joules, if 2 significant figures)
The molar mass of sodium is 22.99 ㅤ ㅤ ㅤ 22.99 (28) = 643.72 mol now multiply by avogrados number to find the number of atoms. ㅤ ㅤ ㅤ 643.72 (6.022 x 10^23) = 3.88 x 10^26 number of atoms
For this problem we use the wave equation. It is expressed as the speed (c) is equal to the product of frequency (f) and wavelength (v).
c = v x f
We know the wavelength of the an red light which is 6.5 x 10^-7 m. Now, we solve for the wavelength of the unknown wave to see the relation between the two waves.
2.998 X 10^8 = 5.3 X 10^15 X v
v = 2.998 X 10^8 / (5.3 X 10^15) = 5.657 X 10^-8 m
Therefore, the wavelength of the unknown wave is less than the wavelength of the red light.
The process where fossil fuels, forests, or other carbon-containing substances are burned, addin more carbon dioxide to the air is the combustion.
Some examples of combustion are:
Fossil fuel:
Carbon + O2
C + O2 -> CO2
Forests (wood)
Wood = cellulose = [C6H10O5]n
[C6H10O5]n + 6nO2 = 6n CO2 + 5n H2O
So, in general the combustion of organic matter produces CO2 and water.
