which laboratory activity involves a chemical change?\nleaving a copper penny in vinegar until it turns…

which laboratory activity involves a chemical change?\nleaving a copper penny in vinegar until it turns green\nboiling saltwater for several minutes until only solid salt remains\nextracting iron filings from a sand mixture using a magnet\ncrushing a rock with a hammer to extract mineral deposits

which laboratory activity involves a chemical change?\nleaving a copper penny in vinegar until it turns green\nboiling saltwater for several minutes until only solid salt remains\nextracting iron filings from a sand mixture using a magnet\ncrushing a rock with a hammer to extract mineral deposits

Answer

Brief Explanations:

A chemical change results in a new substance being formed. When a copper penny is left in vinegar and turns green, copper reacts with acetic - acid in vinegar and oxygen in the air to form copper acetate and other copper - containing compounds (a new substance). Boiling saltwater is a physical change (evaporation of water leaving salt). Extracting iron filings with a magnet is a physical separation. Crushing a rock is a physical change (changing the physical form).

Answer:

leaving a copper penny in vinegar until it turns green