I'm pretty sure it is the 2nd one.
The weighted average atomic mass of Silicon is 28.1
(27.98 x .9223) + (28.98 x .0468) + (29.97 x .0309)
= 25.81 + 1.36 + .93
= 28.1
I cant entirely tell for now but an article on rodioactivity should solve the problem
Correct answer is chemical energy.
Reason:
For the chemical reactions to occur, energy is to be supplied for breaking and reorganization of bonds. This energy can be in form of heat, light, etc. Since, breaking of bonds results in chemical reactions to occur, t<span>he energy stored in molecular bonds is called Chemical energy.</span>
Answer : The molar mass of unknown substance is, 39.7 g/mol
Explanation : Given,
Mass of unknown substance = 9.56 g
Volume of solution = 100.0 mL
Molarity = 2.41 M
Molarity : It is defined as the number of moles of solute present in one liter of volume of solution.
Formula used :

Now put all the given values in this formula, we get:


Therefore, the molar mass of unknown substance is, 39.7 g/mol