Betty placed an unknown powder in a zip lock bag. When she added water to the bag, the powder bubbled, and it disappeared. When the bubbling stopped, the bag contained a clear liquid and a lot of gas.What is the MOST OBVIOUS indicator a chemical reaction occurred?
• There was a change in temperature.
• The powder changed color.
• The powder mixed with the water.
• A gas was formed
• A gas was formed
Are you sure explain
Yes, the most obvious indicator that a chemical reaction occurred is the formation of a gas. This is because the gas is a new substance that was not present before the reaction took place. The other options - change in temperature, change in color, and mixing with water - can also indicate a chemical reaction, but the formation of a gas is the most direct evidence of a chemical change occurring.
There are several different indicators that a chemical change has taken place.
Which of the following examples would be considered an indicator that a chemical reaction has taken place? (1 point)
• The shape of paper changes as it is cut
• A Substance has dissolved
• A liquid freezes
• Heat is given off after mixing two substances
Heat is given off after mixing two substances
Explanation: The release of heat after mixing two substances indicates an exothermic reaction, which is a clear indicator of a chemical change taking place. The other options do involve physical changes or phase changes, but they do not necessarily indicate a chemical reaction.
Are you correct, explain please
I apologize for the confusion in my previous response. Here is the correct explanation:
Heat is given off after mixing two substances: This is a clear indicator that a chemical reaction has taken place. The release of heat often signifies an exothermic reaction, where energy is being released as a result of a chemical change occurring.
The other options listed do not necessarily indicate a chemical reaction:
- The shape of paper changes as it is cut: This is a physical change, as the paper undergoes a physical transformation without any change in its chemical composition.
- A substance has dissolved: Dissolving is a physical change in which a substance mixes uniformly with another without a chemical reaction.
- A liquid freezes: Freezing is also a physical change, as the liquid undergoes a phase change from a liquid to a solid without any alteration in its chemical composition.
Therefore, heat being given off after mixing two substances is the indicator that a chemical reaction has taken place.