The correct answer is C. Slicing through a block of sodium
Explanation:
Physical changes imply a change in density, state, shape, volume, etc. of a substance, but not changes in the chemical properties or chemical composition of it. Due to this, physical changes include processes such as boiling a substance, cutting it or freezing it as these processes only affect physical properties. On the opposite, processes such as oxidation or combustion that affect the composition of a substance lead to chemical changes.
According to this, the one that is an example of physical change is "Slicing through a block of sodium" because this process involves only a change in the volume or shape of the substance that is the block of sodium which means it changes physically but its identity and chemical properties remain intact.
