Answer:
120g Using Density Equation.
Explanation:
Density =mass/volume
We need to the solve for the mass.
Mass=Density * Volume
Mass= 2.40 g/ml * 50.0 ml = 120g
Answer:
The energy difference between these 2p and 2s orbitals is 
Explanation:
Wavelength of the photon emitted = 
Energy of the photon will corresponds to the energy difference between 2p and 2s orbital = E
Energy of the photon is given by Planck's equation:

h = Planck's constant = 
c = Speed of the light = 


The energy difference between these 2p and 2s orbitals is 
Mass of solute ( m1 ) = 50.0 g
mass of solvent ( m2 ) = 150.0 g
Therefore:
m/m = ( m1 / m1 + m2 )
m/m = ( 50.0 / 50.0 + 150.0 )
m/m = ( 50.0 / 200 )
m/m = 0.25
Answer: C.) It burns and causes lung cancer