Answer is: <span>a. two 511 kEv photons are formed.
</span><span>When the positrons reach thermal energies, they start to interact with electrons by annihilation.</span>
Positron-emission tomography<span> (</span>PET)<span> is a </span>nuclear medicine functional imaging<span> technique that is used to observe metabolic processes in the body. The system detects pairs of </span>gamma rays<span> emitted indirectly by a </span>positron<span>-emitting </span>radionuclide.
The question is incomplete, here is the complete question:
At 20°C the vapor pressure of benzene 
is 75 torr, and that of toluene 
is 22 torr. Assume that benzene and toluene form an ideal solution.
What is the mole fraction of benzene in the solution that has a vapor pressure of 38 torr at 20°C? Express your answer using two significant figures.
<u>Answer:</u> The mole fraction of benzene is 0.302
<u>Explanation:</u>
Let the mole fraction of benzene be 'x' and that of toluene is '1-x'
To calculate the total pressure of the mixture of the gases, we use the equation given by Raoult's law, which is:
We are given:
Vapor pressure of benzene = 75 torr
Vapor pressure of toluene = 22 torr
Vapor pressure of solution = 38 torr
Putting values in above equation, we get:
![38=[(75\times x)+(22\times (1-x))]\\\\x=0.30](https://tex.z-dn.net/?f=38%3D%5B%2875%5Ctimes%20x%29%2B%2822%5Ctimes%20%281-x%29%29%5D%5C%5C%5C%5Cx%3D0.30)
Hence, the mole fraction of benzene is 0.30
Answer:
Swimming is lots of fun for people of all ages and children especially love getting in the water and enjoying themselves. It helps people get calm and with elders to
Explanation:
Answer:
1.878g
Explanation:
Volume = 30.0ml
Density = 0.626gcm−3
Mass = ?
Be careful in this kind of questions to check for the units. In this case one has to remember 1 mL equal 1 cm³ so density = 0.626g/ml
The relationship between all three parameters is given by the equationn below;
Mass = Density * Volume
Mass = 0.626g/ml * 30 = 1.878g
