Question 17
The subscript 2 is the atomic number for helium and subscript 4 is the mass number for Helium
<u><em>explanation</em></u>
when writing down an isotope of an element the mass number of that isotope is written in upper side of the chemical symbol, while atomic number is written on the lower side.
Since 4 is on upper side it is the mass number of He, while 2 is the atomic number since it is on lower side.
Question 18
The type of radiation emitted when polonium -212 form lead 208 is an alpha particle
<u><em>explanation</em></u>
Alpha decay is a decay in which an atomic nuclei emit an alpha particles and be transformed into different atomic nuclei with a mass number that is reduced by 4
polonium 212 is reduced by 4 to form lead 208 therefore it undergo alpha particle decay.
Simply saying, enthalpy is the measure of heat content of a system at constant pressure. Thus it is the thermodynamic potential of a system, which is obtained by summing internal energy(U) & Product of pressure(p) & volume(V) of a system.
I think it is B) 18 but you'd have to check. Help?
Yes. That is a mixture. You are allowed to remove the sugar because there is sugar molecules in the water.
Ionic compound
Al +3 charge, Aluminum
S -2 charge, Sulfur
Al2S3
