Answer:
Demonstration 1 showed a chemical change because a new gaseous substance was formed, and demonstration 2 showed a physical change because liquid water became water vapor.
Explanation:
Chemical changes alter the chemical makeup of a subject, and a physical change only alters the appearance of a subject, not the chemical makeup.
They work by lowering the activation energy
Answer:

Explanation:
Mass ( m ) = 52 kg
Acceleration ( a ) = 5 m / s²
Force ( F ) = ?
According to Newton's second law of motion ,



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