Question

A student was given two clear liquids; a colorless liquid and a dark-blue liquid. The student was asked to combine the liquids in a beaker and record observations. Which of the following results, if true, would provide the best evidence that a chemical change took place when the liquids were combined
1The resulting mixture was cloudy.
2The total volume of the mixture was equal to the sum of the initial volumes.
3The resulting liquid was light blue.
4The liquids formed two separate layers in the beaker.

Answer 1

Answer:

1. The resulting mixture was cloudy.

Explanation:

There are 5 observations that can be observed when a chemical change takes place:

1. Color change.

2. Temperature change.

3. Formation of precipitate.

4. Production of gas.

5. Light Emission.

1st option clearly implies that a precipitate has been formed, which according  to the 3rd point as mentioned above is an evidence of a chemical change.

3rd option shows a color change but is not the best evidence because it might also be that dilution has taken place, which isn't a chemical change. Hence, it isn't the best evidence.

Therefore, 1st option is the best choice.

Answer 2

3 The resulting liquid was light blue.

Of the ten characteristics of chemical reactions, the occurrence of color changes is the characteristic that is most easily seen and known quickly, so the third choice is the most appropriate answer.

Further Explanation

Chemical changes are changes in a substance or material that causes the formation of new substances. The characteristics of chemical change are: new types of substances are formed, substances that change cannot return to their original form, followed by changes in chemical properties through chemical reactions. During chemical changes, the mass of the substance before the reaction is the same as the mass of the substance after the reaction.

Different chemical reactions are used together in chemical synthesis to produce the desired compound product. In biochemistry, a series of chemical reactions are catalyzed by enzymes to form metabolic pathways, where synthesis and decomposition that are normally not possible in cells are carried out.

Chemical properties are properties for which chemical changes are needed.

The nature of matter tends to carry out chemical reactions, including:

• Limitation
• Power of Ionization
• Reactivity
• Solubility
• Bias / can not rot

Characteristics of Chemical Reactions

Here are ten characteristics of chemical reactions that are most easily observed.

• Gas bubble formation.
• Sediment formation.
• Discoloration.
• Temperature change.
• Light Emitting.
• Volume Change Occurs.
• Changes in Conductivity.
• Odor changes occur.
• Taste change.
• There was a change in Boiling Point and Freezing Point.

Learn more

definition of chemical changes brainly.com/question/13971733

characteristics of chemical reactions brainly.com/question/13971733

Details

Grade: Middle School

Subject: Chemistry

keywords: Chemical changes, characteristics of chemical reactions