Answer:
characteristic properties of an element are the defining properties of that element and it does not change with quantity of the element used.
Explanation:
the amount or the quantity of the element used does not affect the characteristic property of the element. it does not matter is the if the amount or the quantity of the element used in the reaction is large or the small the characteristic properties like boiling point, melting point, density, thermal conductivity, etc remain the same or remain constant.
Exothermic reactions:
1) release heat to the surroundings
2) the change of enthalpy, ΔH, is negative: ΔH < 0
3) the temperature of the system increases
With that you can conclude about every equation given:
<span>NH3(g) + 12.0 kcal → ½N2(g) + 3/2 H2(g) : is not exothermic because heat in the side of the reactants means that heat is being used, not released.
C(graphite) → C(diamond), ΔH = - 0.45 kcal : is exothermic because ΔH is negative
C + 2S → CS2, ΔH = 27,550 cal: is not exothermic because ΔH is positive
CH4 + 2O2 → CO2 + 2H2O + 212,800 cal : is exothermic because heat appears as a product of the reaction, which means that it is released.
2H2O → 2H2 + O2, ΔH = +58 kcal : is not exothermic because ΔH is positive.</span>
<span>(2) butynu........................</span>
