Answer:
The answer is: (a) positive; (b) negative.
Explanation:
The change in enthalpy (ΔH) of a reaction is the amount of energy absorbed or released during a chemical reaction carried out at constant pressure.
a) In an endothermic chemical reaction, heat energy is absorbed by the system from the surrounding. Therefore, the sign of enthalpy change for an endothermic process is positive, ΔH= positive.
b) In an exothermic chemical reaction, heat energy is released by the system into the surrounding. Therefore, the sign of enthalpy change for an exothermic process is negative, ΔH= negative.
Answer:
HF - hydrogen bonding
CBr4 - Dispersion
NF3 - Dipole-dipole
Explanation:
Hydrogen bonding occurs when hydrogen is covalently bonded to a highly electronegative atom such as fluorine, chlorine nitrogen, oxygen etc. Hence the dominant intermolecular force in HF is hydrogen bonding.
CBr4 is nonpolar because the molecule is tetrahedral and the individual C-Br dipole moments cancel out leaving the molecule with a zero dipole moment hence the dominant intermolecular force are the dispersion forces.
NF3 has a resultant dipole moment hence the molecules are held together by dipole-dipole interaction.
The values of the coefficients would be 4, 5, 4, and 6 respectively.
<h3>Balancing chemical equations</h3>
The equation of the reaction can be represented by the following chemical equation:
ammonia (g) + oxygen (g) ---> nitrogen monoxide (g) + water (g)
+
--->
+ 
Thus, the coefficient of ammonia will be 4, that of oxygen will be 5, that of nitrogen monoxide will be 4, and that of water will be 6.
More on balancing chemical equations can be found here: brainly.com/question/15052184
#SPJ1
Answer:
a lot that's why it's really hot