Question

1. students mixed baking soda and vinegar in two different setups: trial 1: a sealed flask was placed on a scale. the scale reading was 150 g before and after the reaction. trial 2: an unsealed flask was placed on a scale. the scale reading was 150 g before and 144 g after the reaction. which two statements best explain the difference between trial 1 and trial 2? select two correct answers. in trial 2, some atoms were destroyed, which caused the decrease in mass. in trial 2, gas escaped from the flask, so the scale showed a lower mass. in trial 1, no new substances formed, so the mass did not change. in trial 1, the sealed flask kept all the atoms inside, so the mass stayed the same.

Explanation:

In a chemical reaction, mass is conserved according to the law of conservation of mass. In Trial 1, the sealed flask prevents any substances (including gases) from leaving, so the mass remains the same. In Trial 2, the unsealed flask allows gas (produced by the reaction of baking - soda and vinegar) to escape, resulting in a decrease in the measured mass on the scale. Atoms are not destroyed in a chemical reaction as per the law of conservation of mass. A new substance is formed in the reaction of baking - soda and vinegar in both trials.

Answer:

• In Trial 2, gas escaped from the flask, so the scale showed a lower mass.
• In Trial 1, the sealed flask kept all the atoms inside, so the mass stayed the same.