Indicate whether each of these reactions is endothermic or exothermic. NH4CI(S) - NHA" (aq) + Cl(aq) AHxn = 14.7 kJ
NaOH(s) Nat(aq) + OH (aq) AHixo = -44.5 kJ
CH2(g) + 2O2(g) CO2(g) + 2H20(g) Hrxn < 0
CH3COOH(aq) + NaHCO3(s) + CO2(g) + H2O(l) + Na"(aq) + CH3COO(aq)
AHxn > 0

1. is endothermic

2. is exothermic

3. is exothermic (less than zero)

4. is Endothermic, greater than zero

Explanation:

The key to answering this is knowing how we interpret the values of delta H when given at the side of a reaction.

To know what the value of delta H means at that point, we should understand whether it is greater than zero or less than zero.

When it is greater than zero it is endothermic, when it is negative i.e less than zero it is exothermic

So;

1. is endothermic

2. is exothermic

3. is exothermic (less than zero)

4. is Endothermic, greater than zero

the dissolution of polymer can be thermodynamically described in 2 steps.