# What happens to the entropy when a rubber band is stretched?

## What happens to the entropy when a rubber band is stretched?

When stretched the polymer strands should be more aligned and straighten out along the direction of the stretching. When you relax it the strands go in all directions, or become more disordered. For this change the entropy increases, which means the heat is positive.

### Why does a rubber band heat up when stretched?

When molecules, not just rubber molecules, but any molecules, form crystals, they give off heat. This is why the rubber band feels hot when its stretched. When you let go of the rubber band, the polymer molecules break out of those crystals. Whenever molecules break out of crystals, they absorb heat.

#### Why is stretching a rubber band exothermic?

A stretched rubber band feels warm against your lip, meaning that heat is released for stretching. Stretching is an exothermic process, so AH < 0. Similarly, when the rubber band gets limp, the process is endothermic, and AH > 0. Let it limp and absorb heat until it reaches the indoor temperature.

How temperature affects the stretch of a rubber band?

The rubber band actually expands when it gets colder! This occurs because of the unusual polymer structure of rubber. When the long chains get hotter and vibrate, they actually shorten, causing the material to contract. When the chains cool down, they relax and stretch out, causing the material to expand.

Is stretching a rubber band exothermic or endothermic?

By placing the rubber band against their lips, students may detect the slight warming that occurs when the rubber band is stretched (exothermic process) and the slight cooling effect that occurs when the rubber band contracts (endothermic process).

## Is stretching of rubber band is reversible?

Explanation: If we stretch a rubber band with force of our hands, it undergoes a change and its length increases. But, on releasing the force, the rubber band comes back to its original length. So, the stretching of rubber band is a reversible change, the stretching of a spring is also a reversible change.

### Which force is used to stretch a rubber band?

elastic force
When a rubber band is stretched, the force acting on the rubber band is known as the elastic force.

#### Is stretching a rubber band endothermic?

Is stretching a rubber band chemical or physical?

physical change
Stretching a rubber band is a physical change because the size of the rubber band changes. The color of the rubber band sometimes can change as well when it is stretched. However, the material that the rubber band is made of does not change.

How do you make rubber more stretchy?

1. Spray the rubber with silicone spray.
2. Keep the rubber in the plastic bag for three to seven days.
3. Lift the bagged piece of rubber and bend it to check for pliability.
4. Heat some water in a stew pot on the stove.
5. Set the stew pot in the sink and submerge the rubber in the water to soften it.

## What type of change is stretching a rubber band?

Stretching of a rubber band is a physical change.

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