Question

Trini adds 10g if baking soda to 100g of vinegar. The mixture begins to bubble. When the bubbling stops, Trini finds the mass of the resulting mixture. She determines its mass is 105g. Why has the mass changed?

F) A gas has formed and left the mixture.

G) Vinegar evaporated during the experiment.

H) Mixtures are always less massive than their parts.

I) Matter was destroyed when vinegar reacted with baking soda.

Answer 1

The mass has changed because a gas has formed and left the mixture.

Answer: Option A

Explanation:

According to law of conservation of masses which is followed by every chemical reaction, the sum of masses of the reactants equal to the sum of the masses of the products. But in this case of baking soda of 10 g reacting with 100 g of vinegar is giving a resulting mixture of 105 g.

So, this mismatch in the resultant mass of the product with the sum of masses of the reactants is due to the formation of bubbles in the chemical reaction between baking soda and vinegar. This gas bubbles formed on reaction of vinegar with baking soda will leave the mixture.

As we known from conservation of mass, the resultant mixture should be equal to the sum of mass of vinegar and baking soda reacted which would have been equal to 110 g ( baking soda 10 g +100 g of vinegar). But we have obtained only 105 g of resultant mixture so the remaining 5 g has been converted into gas and left the mixture.