Which of the following is NOT an example of an endothermic reaction? An ice cube melts on a summer day.
An egg cooks in a frying pan.
Water evaporates off a sidewalk.
Fireworks are displayed in the night sky.

Fireworks are displayed in the night sky

Explanation:

Fireworks are exothermic

C. Fireworks are displayed in the night sky

Explanation: I got it right on the quiz. :)

c is having 4 valence electrons and is bonded to three hydrogens and one sulphur atom, therefore, the number of bond pair is equal to four. as all the valence electrons are used in forming the bonds so, there is no lone pair left on carbon.

s is having 6 valence electrons and is bonded to one other sulfur atom and one carbon atom, therefore, the number of bond pair is equal to 2. as only two valence electrons are used in forming the bonds so, four electrons are left. therefore, two lone pairs are present on s.