Which of the following could provide definitive evidence of a chemical reaction? Choose two correct answers.
Liquid water has frozen to form ice
A new substance, rust, has form
A solid had dissolved in a liquid
A new substance, oxygen gas, has formed
The two correct answers are:
1. A new substance, rust, has formed - This is evidence of a chemical reaction because rust is formed through the oxidation of iron, which involves a chemical change.
2. A new substance, oxygen gas, has formed - This is evidence of a chemical reaction because the formation of oxygen gas typically involves the breaking and forming of chemical bonds, indicating a chemical change.
The two correct answers that could provide definitive evidence of a chemical reaction are:
1. A new substance, rust, has formed.
2. A new substance, oxygen gas, has formed.