Question

A student is performing a chemistry experiment. The student adds 10 grams of reactant A and 5 grams of reactant B into a beaker. The student notices a bubbling reaction with a considerable amount of gas given off while a white solid residue remains in the beaker. Which observations below are accurate about this experiment? Select ALL that apply.

Responses

A A chemical change occurred. A chemical change occurred.

B Only physical changes occurred in the beaker. Only physical changes occurred in the beaker.

C The products include a gas and the substance remaining in the beaker. The products include a gas and the substance remaining in the beaker.

D The remaining products in the beaker may have less than 15 grams of mass. The remaining products in the beaker may have less than 15 grams of mass.

E The reactants changed phase from solid to gas but stayed the same chemically.

Answer 1

The observations indicate that a chemical change occurred, as evidenced by gas production and the formation of a new solid residue. The products of the reaction include a gas and the remaining solid, and the mass of these remaining solids may be less than the original total mass of reactants due to the gas escaping the system.

Step-by-step explanation:

Based on the observations of the chemical experiment, where 10 grams of reactant A and 5 grams of reactant B were combined with a bubbling reaction and the production of a solid residue, the following statements can be determined:

• A chemical change occurred. The presence of a gas being produced and a new solid residue signifies a chemical reaction. Bubbling in particular is a strong indicator of gas formation during a chemical reaction.
• The products of the reaction include a gas and the remaining substance in the beaker. This statement aligns with the evidence of bubbling and the formation of a white solid residue.
• The mass of the remaining products in the beaker may be less than 15 grams. Due to the law of conservation of matter, while the total mass remains constant in an isolated system, some of the mass in this experiment may be lost to the environment as a gas, resulting in a lower mass for the solid residue remaining.

Statements regarding only physical changes and the reactants changing phase but staying the same chemically are inaccurate, as the evidence points to a chemical reaction having taken place.