At the end of which of the following reactions will the temperature of the surrounding increase? H2 (g) + F2 (g)-->2HF (g) ΔH = -542.2 kJ

H, 2, (g) + F, 2, (g)-->2HF (g) ΔH = -542.2 kJ
6C(s) + 3H2 (g)→ C6H6 (g) ΔH° = +49.03 kJ

C + O2 → CO2 ΔH = -393.5 kJ

C + O, 2, → CO, 2 , ΔH = -393.5 kJ

CaCO3(s) CaO(s) + CO2(g) ΔH = +400.5 kJ

Consider a culture medium on which only gram-positive organisms such as staphylococcus aureus colonies can grow due to an elevated nacl level. a yellow halo surrounds the growth, indicating the bacterium fermented a sugar in the medium, decreasing the ph as a result and changing the color of a ph indicator chemical. this type of medium would be referred to as a differential and enrichment culture.