Are the following examples of chemical or physical changes?
Column A
1.
Digesting lunch:
Digesting lunch
2.
Cutting your hair:
Cutting your hair
3.
Crumbling up your snack wrapper:
Crumbling up your snack wrapper
4.
Grilling chicken:
Grilling chicken
Column B
a.Chemical Changes
b.Physical Changes
Column A:
1. Digesting lunch: Chemical change
2. Cutting your hair: Physical change
3. Crumbling up your snack wrapper: Physical change
4. Grilling chicken: Chemical change
Column B:
a. Chemical Changes
b. Physical Changes
Column A:
1. Digesting lunch: This is a chemical change because the food is broken down and chemically transformed during digestion.
2. Cutting your hair: This is a physical change because the hair is being physically altered in length but no new substances are being formed.
3. Crumbling up your snack wrapper: This is a physical change because the wrapper is being physically broken into smaller pieces but no new chemical substances are being created.
4. Grilling chicken: This is a chemical change because the heat from grilling causes chemical reactions in the chicken, leading to the formation of new compounds that change its texture and taste.
Column B:
1. Digesting lunch: a. Chemical Changes
2. Cutting your hair: b. Physical Changes
3. Crumbling up your snack wrapper: b. Physical Changes
4. Grilling chicken: a. Chemical Changes
To determine if the examples given are chemical or physical changes, we need to understand the definitions of these two types of changes.
A chemical change occurs when a substance undergoes a transformation in its chemical composition, forming new substances with different properties. This usually involves the breaking and forming of chemical bonds.
A physical change, on the other hand, does not involve a change in the chemical composition of a substance. It usually involves a change in the physical properties such as shape, size, or phase (solid, liquid, gas) without forming new substances.
Now, let's analyze each example:
1. Digesting lunch:
Digesting lunch is a chemical change because the food you consume undergoes a complex process involving enzymes and acids in your digestive system, breaking down the molecules of food into simpler substances that can be absorbed by your body. During digestion, the chemical composition and properties of the food change significantly.
2. Cutting your hair:
Cutting your hair is a physical change because it only alters the physical appearance and length of your hair. The chemical composition of the hair strands remains the same.
3. Crumbling up your snack wrapper:
Crumbling up your snack wrapper is a physical change because it changes the shape and possibly the size of the wrapper, but it does not alter its chemical composition.
4. Grilling chicken:
Grilling chicken is both a chemical and physical change. The physical change occurs when the chicken cooks, causing the proteins in the meat to denature and the water within the chicken to evaporate, resulting in a change in its texture, color, and taste. The chemical change occurs due to the Maillard reaction, where the heat causes a reaction between amino acids and reducing sugars in the chicken, resulting in the formation of flavorful compounds.
To summarize:
- Digesting lunch: Chemical change
- Cutting your hair: Physical change
- Crumbling up your snack wrapper: Physical change
- Grilling chicken: Both chemical and physical change