C. The neutron number.
An element is determined based on how many protons has, if the protons number change then you got a new element.
If the number of neuron change you got the same element except it will be a bit heavier or lighter if you are gaining or loosing neutrons. Those variations of an element are called the isotops of the element.
The protons and neutrons toghether form the nucleus of the atom that is heavy and dense as an elephant.
The electrons are light as fleas and stay on the shels of around the nucleus and if they are more then the number of protons they make the atom negatively charged and vice versa.
<span>A ) AB is a compound . Ionic compound because the electronegativity differs a lot in both !
</span><span>
B) Same
C ) Compound . But the bond between them is covalent .
D ) AB is an ionic compound . A is the cation and B is the anion </span>
Answer:
The ΔH is 5.5 kJ/mol and the reaction is endothermic.
Explanation:
To calculate the ∆H (heat of reaction) of the combustion reaction, that is, the heat that accompanies the entire reaction, you must make the total sum of all the heats of the products and of the reagents affected by their stoichiometric coefficient ( number of molecules of each compound participating in the reaction) and finally subtract them:
Combustion enthalpy = ΔH = ∑H products - ∑Hreactants
In this case:
ΔH = 15.7 kJ/mol - 10.2 kJ/mol= 5.5 kJ/mol
An endothermic reaction is one whose enthalpy value is positive, that is, the system absorbs heat from the environment (ΔH> 0).
<u><em>The ΔH is 5.5 kJ/mol and the reaction is endothermic.</em></u>
