In the first law of thermodynamics, ΔE=Q−W , what does ΔE stand for? the change in the internal energy of the system

the work done by the piston

the heat added to the system

the internal energy of the system

Ithink the answer would be a 

The chemical reactions lab we did is typically called a "copper plating lab,  because the acid solution cleaned the pennies and made the copper look shinier;   the acid solution cleaned the paperclips and made them look like pennies;   &   the copper from the pennies was removed, and then added to the paperclips. 

B. that is the answer

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