Which of these is an example of a physical change? a banana ripening in the air hydrogen burning in the air zinc reacting with an acid liquid water turning into vapor

An example of a physical change is liquid water turning into vapor. Physical change is that it may involve a change in phase but does not involve a change in molecular structure.

Water into water vapor is a physical change

In the matter of a substance, there is a process of change.

2 changes occur in the mater, namely: changes in physics and chemical changes

Classification uses the principle of the initial and final state of the substance.

Changes in physics are changes in the matter which in the process do not cause new substances. So the properties of the particles remain the same.

Generally, the physical changes that occur are changes in shape/size and size, changes due to heating, or changes in volume

Chemical changes are changes in the process produce new substances that are different from the initial/forming substances. Chemical changes are usually known as chemical reactions. So there are products/reactions and reactants

So in chemical changes, there is a change in the molecule/particle

If we see the answers

1. ripe banana

In the process of ripening bananas, there are changes in skin color (green to yellow due to loss of chlorophyll), changes in sugar levels (increase in fructose/glucose) and softness of fruit flesh

So that the ripening process of bananas is a chemical change

2. Hydrogen  burning in the air

Burning is a chemical process that involves fuel and oxidizing agents that will produce products and heat (removing heat)

Burning hydrogen will produce a water vapor compound

H₂ + O₂ ---> H₂O

So combustion of hydrogen is a chemical change

3. The reaction of zinc with acid

This reaction is one of the reduction and oxidation reactions where zinc is the reducing agent that undergoes oxidation and acid reaction as an oxidizer which undergoes a reduction reaction

Examples of reactions with HCl (hydrochloric acid)

Zn (s) + 2HCI (aq) ⇒ ZnCl₂ (aq) + H₂ (g)

Hydrogen gas and zinc chloride are formed here

So zinc reacts with acids including chemical changes

4. water becomes water vapor

This process is included in the evaporation process, where there is a change in the liquid phase (water) into a gas (water vapor) through the heating process. So the nature of the particles is the same and the shape can be made back to the original substance. The only thing that changes is the physical.

So water into water vapor is a change in physics

The difference between physical and chemical change  

example of a chemical change link

examples of chemical changes link

Grade: high school

Subject: chemistry

Chapter: material changes

Keywords: chemical change, physical change, hydrogen combustion, evaporation, ripe banana, reduction, oxidation, zinc, metal

1 a

2 d

3 a

4 c

explanation:

in scientific notation, the value of the  speed of light in a vacuum

  will be written as 2.995 * 10^8. when this value is represented in the form of

  a * 10^b, then, a = 2.995 and b = 8.

the value of the speed of light in a vacuum given above can also be rounded up to approximately 300000000. in this case, the scientific notation will be written as 3 *10^8.