Answer : The enthalpy of formation of 
is, -812.4 kJ/mole
Explanation :
According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.
According to this law, the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation. That means the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.
The formation of will be,
The intermediate balanced chemical reaction will be,
(1) 
(2) 
(3) 
(4) 
Now adding all the equations, we get the expression for enthalpy of formation of will be,
Therefore, the enthalpy of formation of is, -812.4 kJ/mole
Answer:
A. 3.5ml
Explanation:
lowest point of liquid or meniscus
The correct answer would be we have no other frame of reference besides the sky. We could actually tell we are moving because of the shifting of stars in the sky over time. But really, “A” would be your answer. We have the same momentum of the earth. It’s like being on a train at a constant speed. The only way you know you’re moving is if you look out the window or the speed changes causing you to be pushed around. Same thing with earth, our only reference is the sky
Explanation:
An alpha particles is basically a helium nucleus and it contains 2 protons and 2 neutrons.
Symbol of an alpha particle is 
. Whereas a neutron is represented by a symbol 
, that is, it has zero protons and only 1 neutron.
Therefore, reaction equation when an aluminum- nuclide transforms into a phosphorus- nuclide by absorbing an alpha particle and emitting a neutron is as follows.
