Answer : The value of 
is, -103.4 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 given main reaction is,
The intermediate balanced chemical reaction will be,
(1) 
(2) 
Now reversing and multiplying by 2 of reaction 1 and 2 then adding all the equations, we get :
(1) 
(2) 
The expression for will be,
Therefore, the value of is, -103.4 kJ
Answer:
B. Aluminum is a good conductor of heat
Explanation:
Physical properties are usually those that can be observed using our senses such as color, luster, freezing point, boiling point, melting point, density, hardness and odor. The Physical Properties of Aluminum are as follows: Color : Silvery-white with a bluish tint.
The answer is c it is Carbon Dioxide
The part of an atom that is actively exchanged or shared in a chemical bond is ELECTRON.
An atom is made up of three sub particles, which are electron, proton and neutron. The proton and the neutron are located in the nucleus of the atom and they make up the major mass of the atom. The electron is located outside of the nucleus and it orbit around the nucleus; it has negligible mass. The electron is negatively charged and because it is located outside of the nucleus, it is the one that is always involved in chemical reactions. There are different types of chemical bonds in chemical compounds and it is electrons that are normally used to form these bonds. During bond formation, electrons can either be donated or shared.
