Question

mixing baking soda and vinegar makes the temperature of the solution decrease and release carbon dioxide. which conclusion about this investigation is not valid?

• mixing the chemicals caused them to absorb heat.
• a chemical reaction took place.
• new elements were formed.
• the procedure caused a gas to be formed.

Explanation:

1. When baking soda and vinegar react, the temperature drop means heat is absorbed from the surroundings, so the first conclusion is valid.
2. The production of a new gas (carbon dioxide) and temperature change confirm a chemical reaction occurred, so the second conclusion is valid.
3. A chemical reaction forms new substances (like carbon dioxide, water, and sodium acetate), but it does not create new elements. The elements present (sodium, hydrogen, carbon, oxygen) are just rearranged, so this conclusion is invalid.
4. The problem explicitly states carbon dioxide (a gas) is released, so the fourth conclusion is valid.

Answer:

New elements were formed.