Answer : The value of 
for the reaction is, -135.2 kJ
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) 
We are dividing the reaction 1, 2 and 3 and reversing reaction 3 and then adding all the equations, we get :
(1) 
(2) 
(3) 
The expression for enthalpy of formation of will be,
Therefore, the value of for the reaction is, -135.2 kJ
Halogens are elements that can be found in group 7 of the periodic table. They have 7 electrons in their outer shell and thus can form only a single covalent bond with other elements. Examples of halogens include chlorine, bromine and fluorine. A carbon compound that is covalently bonded with chlorine or bromine is called a halocarbon.
Covalent and ionic bonds are two different types of chemical bonding. Covalent bonds involve the sharing of electrons between 2 atoms while ionic bonds involve the complete transferring of electrons from one atom to another. Covalent bonds usually form between two nonmetals while ionic bonds usually form between a metal and a nonmetal.
I hope this helps. Let me know if anything is unclear.
Answer:
0.4444 g/cm³ ≅ 0.44 g/cm³ (2 significant figures).
Explanation:
<em>d = m/V,</em>
where, d is the density of the material (g/cm³).
m is the mass of the material (m = 28 g).
V is the volume of the material (V = 63.0 cm³).
<em>∴ d = m/V </em>= (28 g)/(63.0 cm³) = <em>0.4444 g/cm³ ≅ 0.44 g/cm³ (2 significant figures).</em>
From the equation above the reacting ratio of KClO3 to O2 is 2:3 therefore the number of moles of oxygen produced is ( 4 x3)/2 = 6 moles since four moles of KClO3 was consumed
mass=relative formula mass x number of moles
That is 32g/mol x 6 moles =192grams
