I'm not sure if what this question is asking but ill be assuming that the average molecular mass is required. An assuming that the abundance of each isotope is 50% the average molecular mass is 69.82 amu.
Answer: 
Explanation:
Electron gain enthalpy is defined as energy released on addition of electron to an isolated gaseous atom.
The amount of energy released will be maximum when the tendency to attract electrons is maximum. As flourine has atomic number of 9 and has electronic configuration of 2,7. It can readily gain 1 electron to attain stable noble gas configuration and hence liberates maximum energy.
Answer:
151.63 g
Explanation:
We first get the number of moles;
Moles = Molarity × volume
= 2.0 × 0.475
= 0.95 moles
1 mole of CuSO4 = 159.609 g/mol
Therefore;
Mass = moles × molar mas
= 0.95 moles × 159.609 g/mol
= 151.63 g
Answer:
Fe₂O₃
Explanation:
To solve this question we must find the moles of Iron in 1.68g. With the difference of the masses we can find the moles of oxygen. The formula will be obtained with the ratio of both amount of moles:
<em>Moles Fe:</em>
1.68g * (1mol / 56g) =0.03moles
<em>Moles O:</em>
2.40g-1.68g = 0.72g * (1mol/16g) = 0.045moles
The ratio O/Fe is:
0.045moles / 0.03moles = 1.5 moles. this ratio is obtained if the formula is:
<h3>Fe₂O₃</h3>
