14. Which of the following is an example of a physical change?

Question

(1 point)
Responses

Burning wood to produce ash and smoke.
Burning wood to produce ash and smoke.

Dissolving sugar in water to make a sweet solution.
Dissolving sugar in water to make a sweet solution.

Rust forming on a metal surface when exposed to moisture.
Rust forming on a metal surface when exposed to moisture.

Baking a cake where the ingredients transform into a new substance.

Answer 1

Dissolving sugar in water to make a sweet solution is an example of a physical change. This process does not create a new substance; the sugar can be recovered by evaporating the water. The other options involve chemical changes, where new substances are formed.

Answer 2

so whats the answer and can you explain why the others are wrong

Answer 3

The correct answer is Dissolving sugar in water to make a sweet solution. This is a physical change because it involves the dissolution of sugar in water, which does not result in the formation of new substances. The sugar retains its chemical identity, and it can be recovered by evaporating the water.

Here’s why the other options are incorrect:

1. Burning wood to produce ash and smoke: This is a chemical change because burning (combustion) involves a reaction where the wood reacts with oxygen and transforms into new substances such as ash and smoke. These products have different properties from the original wood.

2. Rust forming on a metal surface when exposed to moisture: This is also a chemical change. Rust is a new substance (iron oxide) that forms when iron reacts with oxygen in the presence of moisture. The original metal is chemically altered in this process.

3. Baking a cake where the ingredients transform into a new substance: This represents a chemical change as well. The heat causes the proteins and sugars in the cake batter to undergo chemical reactions, leading to the formation of a new substance (baked cake). The original ingredients cannot be separated back into their original forms after baking.

In summary, a physical change is one that does not alter the chemical identity of a substance, while a chemical change results in the formation of new substances.