4. This is an endothermic reaction, what does that mean and how is this illustrated in the video? (What did the reaction do that indicates it is an endothermic reaction?):

Which of these reactions are redox reactions? check all that apply.cd + hcl → cdcl2  + h2cucl2  + na2s → 2nacl + cuscaco3  → cao + co2          2zns + 3o2  → 2zno + 2so2          ch4  + 2o2  → co2  + 2h2o

Describe the interaction that occurs between two objects with the same electrical charge.

Acontrol during an experiment. might change remains constant does not exist does change