Question

Which procedure could be used to demonstrate that matter is conserved during a physical change? Use responses
Responses
Find the mass of a piece of ice. Let the ice melt. Find the mass of the liquid water.
Find the mass of a cup of water. Boil the water. Find the mass of the water that remains.
Find the mass of a raw egg. Cook the egg. Find the mass of the cooked egg.
Find the mass of an apple. Cut the apple and remove the core. Find the mass of the remaining apple

Answer 1

To demonstrate that matter is conserved during a physical change, you need to choose a process that doesn't involve adding or removing any substances, aside from changing the state of the matter. Among the provided responses, the first one can be used to illustrate the conservation of mass in a physical change:

"Find the mass of a piece of ice. Let the ice melt. Find the mass of the liquid water."

Here's why this procedure demonstrates the conservation of matter during a physical change:

1. The mass of the piece of ice is measured while it is in its solid state.
2. The ice undergoes a physical change when it melts, transitioning from a solid to a liquid, but no matter is added or lost during this process – it is just a change in state.
3. After the ice has fully melted, the mass of the resulting liquid water is measured. According to the law of conservation of mass, this mass should be the same as the mass of the ice before melting, provided the process is contained in a closed system that doesn't allow mass to escape or external mass to enter.

For the other responses, while they involve physical changes, they also come with issues that could misrepresent the conservation of mass:

- "Find the mass of a cup of water. Boil the water. Find the mass of the water that remains." This doesn't show the conservation of mass because when you boil the water, some of it turns into steam and can be lost to the surrounding air unless contained in a completely closed system.

- "Find the mass of a raw egg. Cook the egg. Find the mass of the cooked egg." This is problematic because cooking can lead to loss of water through evaporation, and there may be small amounts of material sticking to the cooking vessel, leading to a reduction in mass.

- "Find the mass of an apple. Cut the apple and remove the core. Find the mass of the remaining apple." In this example, mass is intentionally removed (the core), so it doesn't demonstrate the conservation of mass during a physical change.

Consequently, the first procedure most accurately demonstrates the conservation of matter during a physical change, assuming the process occurs in a closed system where no water vapor escapes.