In a container, a solid consisting of clear crystals is combined with a blue liquid and the following observations are obtained:

Question

How many of the listed observations indicate a new substance was formed?

~ The color of the liquid changes from blue to red

~ The solid got larger.

~ Solution temperature changed from 20∘
to 30∘

~ Bubbles were forming in the container

Responses

1
1

2

Answer 1

To determine how many of the listed observations indicate that a new substance was formed, let's analyze each observation:

1. The color of the liquid changes from blue to red: This indicates a chemical change, suggesting that a new substance may have been formed.

2. The solid got larger: This may indicate either a physical change (such as crystallization) or a reaction. By itself, this does not definitively indicate the formation of a new substance.

3. Solution temperature changed from 20°C to 30°C: A temperature change can indicate an exothermic or endothermic reaction, suggesting that a reactant has been transformed into a product, which implies a new substance may have been formed.

4. Bubbles were forming in the container: The formation of bubbles often indicates gas production, which typically occurs during a chemical reaction. This suggests that new substances have likely formed.

Based on the analysis:

• The first observation (color change).
• The third observation (temperature change).
• The fourth observation (bubbles forming).

These observations indicate the formation of new substances. The second observation does not definitively indicate a new substance without further context.

Therefore, 3 observations indicate that a new substance was formed.