Charles law states that volume of gas is directly proportional to temperature at constant pressure
V/T = k
where V - volume , T - temperature and k - constant

where parameters for the first instance are on the left side and parameters for the second instance are on the right side of the equation
in the question it states that the temperature has been increased from 278 K to 231 K but it should actually be temperature is decreased from 278 K to 308 K
substituting the values in the equation

V = 462 cm³
the answer should be D. 462 cm³
The atomic mass of an atom if its mass is approximately equal to carbon-12 will be 12 and in case of 4.5 times carbon-12 will be 54
Atomic mass of an element is the average mass of the atoms of an element which are measured in atomic mass unit. Or we can also say that the atomic mass is actually the weighted mass is a weighted average of all of the isotopes of elements, in which the mass of each element is multiplied by the abundance of that particular isotope.
So the atomic mass of an atom if the mass is approximately equal to carbon-12 then the mass of the element will be equal to 12 as the atomic mass of carbon-12 is 12.
where as the atomic mass of an atom if its mass is approximately equal to 4.5 times as much as carbon-12 will be ⇒ 4.5×12= 54
To know more about atomic mass
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Question in incomplete, complete question is:
Technetium (Tc; Z = 43) is a synthetic element used as a radioactive tracer in medical studies. A Tc atom emits a beta particle (electron) with a kinetic energy (Ek) of
. What is the de Broglie wavelength of this electron (Ek = ½mv²)?
Answer:
is the de Broglie wavelength of this electron.
Explanation:
To calculate the wavelength of a particle, we use the equation given by De-Broglie's wavelength, which is:

where,
= De-Broglie's wavelength = ?
h = Planck's constant = 
m = mass of beta particle = 
= kinetic energy of the particle = 
Putting values in above equation, we get:


is the de Broglie wavelength of this electron.
Answer:
Percent yield of PI3 = 95.4%
Explanation:
This is the reaction:
2P (s) + 3I2 (g) > 2PI3 (g)
Let's determine the moles of iodine that has reacted.
58.6 g / 253.8 g/mol = 0.231 mol
Ratio is 3:2. Let's make a rule of three to state the moles produced at 100 % yield reaction.
3 moles of I2 react to make 2 moles of PI3
0.231 moles of I2 would make (0.231 .2) / 3 = 0.154 moles of PI3
As we have produced 0.147 moles let's determine the percent yield.
(Yield produced / Theoretical yield) . 100 > (0.147 / 0.154) . 100 = 95.4%
Answer: 5
Explanation: add up all the electrons and it will amount to 23. Arranging by the old model for electronic configuration, we have : 2, 8, 8, 5
The last number being 5 represent its valence electron