Question

.

Three students are asked to discuss why the CO2 produced from the reaction

rose upward out of the mouth of the test tube even though CO2 is denser than

air. Select the student that employs correct scientific reasoning.

Student 1: The reason the carbon dioxide rose despite being denser than air is because the heat

caused it to condense.

• Student 2: The carbon dioxide produced by decomposition of baking soda was able to rise above

the air because the oxygen in the test tube was consumed.

• Student 3: The carbon dioxide rose up because the heat expanded the gas and it became less

dense.

O Student 3

OStudent 1

O Student 2

Answer 1

The correct reasoning is provided by Student 3, who explains that the heat from the reaction causes the CO2 to expand and become less dense, allowing it to rise in the cooler surrounding air.

Step-by-step explanation:

The student with the correct scientific reasoning for why the CO2 produced from the reaction rose upward out of the mouth of the test tube even though CO2 is denser than air is Student 3. This student correctly identifies that the heat from the reaction expands the gas, making it less dense than the cooler surrounding air. The notion of gases becoming less dense when heated is explained by the ideal gas law, which states that the density of a gas is inversely proportional to its temperature when pressure is held constant. This expansion allows the CO2 to rise due to the buoyant force exerted by the colder, denser air around it.

Answer 2

Student 3

Step-by-step explanation:

This question lets us know something about how the density of a gas varies with temperature.

When a gas is heated, its molecules spread out and expand. When this happens, the volume of the gas increases. Remember that density is defined as mass/volume. Thus as the volume increases, the density of the gas decreases.

Therefore, the carbon dioxide rose up because the heat expanded the gas and it became less dense.