Write C for chemical change and P for physical change. Give evidence to support your answer.
1. glass breaking
2. a rusting bicycle
3. spoiling food
4. burning paper
5. frying an egg
6. baking a cake
7. melting butter
1. C - glass breaking: When glass breaks, the bonds between the molecules are broken, resulting in a rearrangement of the atoms within the glass. This is a chemical change.
2. C - a rusting bicycle: Rust is formed when iron reacts with oxygen in the presence of water. This chemical reaction results in the formation of iron oxide, which is the rust on the bicycle.
3. C - spoiling food: Spoiling food involves the growth of bacteria or fungi, which break down the organic matter in the food. This is a chemical change.
4. C - burning paper: Burning paper involves a chemical reaction with oxygen, resulting in the release of heat, light, and smoke. The cellulose in the paper is broken down into carbon dioxide and water vapor.
5. C - frying an egg: When an egg is fried, the proteins within the egg undergo a chemical change as they denature and coagulate due to the heat. This causes the egg to solidify and change its texture and color.
6. C - baking a cake: The process of baking a cake involves several chemical reactions, such as the leavening agents reacting with acids to release carbon dioxide, which helps the cake to rise. Additionally, the heat causes the proteins, starches, and fats in the cake ingredients to undergo various chemical changes, resulting in a cooked and finished cake.
7. P - melting butter: Melting butter is a physical change because it involves a change in state from solid to liquid. The chemical composition of the butter does not change during melting.
In 6 sentences, what do you think the difference is between a physical and chemical change? Be specific with your answer!
Physical changes involve a transformation in the physical properties of a substance, such as its shape, size, or state, without altering its chemical composition. In physical changes, the substance still retains its original identity and can be reverted back to its original form. An example of a physical change is when ice melts into water. The ice undergoes a change in state from a solid to a liquid, but its chemical composition remains the same.
On the other hand, chemical changes result in the formation or breaking of chemical bonds, leading to a change in the chemical composition of a substance. Chemical changes are characterized by the formation of new substances with different properties than the original substances. An example of a chemical change is when iron rusts in the presence of oxygen and moisture. The iron reacts with oxygen to form iron oxide (rust), resulting in a change in both the physical and chemical properties of the substance.
In summary, physical changes involve alterations in the physical properties of a substance without changing its chemical composition, while chemical changes involve the formation or breaking of chemical bonds, resulting in a change in the chemical composition of a substance.
1. Glass breaking: Physical change (P) - When glass breaks, the chemical composition of the glass does not change. It is still made up of the same material, only the physical arrangement of the glass particles is altered.
2. Rusting bicycle: Chemical change (C) - Rusting is a chemical reaction that occurs when iron reacts with oxygen in the presence of moisture to form iron oxide (rust). The chemical composition of the iron is changed, indicating a chemical change.
3. Spoiling food: Chemical change (C) - When food spoils, it undergoes chemical reactions due to the growth of microorganisms or the oxidization of its components. This leads to changes in taste, smell, and appearance, indicating a chemical change.
4. Burning paper: Chemical change (C) - When paper burns, it undergoes combustion and chemical reactions with oxygen in the air. The paper is converted into new substances like ash, smoke, and gases, indicating a chemical change.
5. Frying an egg: Chemical change (C) - When an egg is fried, heat causes the proteins in the egg to denature and coagulate, forming a solid structure. The chemical composition of the egg proteins changes, indicating a chemical change.
6. Baking a cake: Chemical change (C) - When a cake is baked, the ingredients, such as flour, sugar, and eggs, undergo chemical reactions with heat. The proteins denature, starches and sugars undergo caramelization, and leavening agents release gas. These changes result in a new product with different properties, indicating a chemical change.
7. Melting butter: Physical change (P) - When butter melts, it changes from a solid to a liquid state due to the increase in temperature. The chemical composition of the butter remains the same, indicating a physical change.
1. Glass breaking: P (physical change)
Evidence: When glass breaks, the composition of the glass does not change. It is still made up of the same molecules and retains its chemical identity.
2. Rusting bicycle: C (chemical change)
Evidence: Rusting involves a chemical reaction between iron in the bicycle and oxygen in the air. This reaction forms a new compound, iron oxide, which gives a reddish-brown color. The chemical composition of the iron is changed during rusting.
3. Spoiling food: C (chemical change)
Evidence: Spoiling food involves the growth of microorganisms like bacteria, fungi, or yeasts that break down the organic compounds in the food. These microorganisms produce enzymes that react with the food, leading to changes in taste, odor, and texture. The chemical composition of the food changes during spoilage.
4. Burning paper: C (chemical change)
Evidence: When paper burns, it undergoes a combustion reaction with oxygen in the air. The paper combines with oxygen to form new compounds, such as carbon dioxide, water vapor, and ash. The chemical composition of the paper changes as it is converted into different compounds.
5. Frying an egg: C (chemical change)
Evidence: When an egg is fried, heat causes the proteins in the egg to denature and coagulate, resulting in a change in texture and color. The chemical composition of the proteins in the egg is altered during frying.
6. Baking a cake: C (chemical change)
Evidence: Baking a cake involves a series of chemical reactions, such as the reactions between baking powder or baking soda and acidic ingredients, the Maillard reaction between proteins and sugar, and the coagulation of proteins. These reactions result in the production of carbon dioxide, giving the cake its fluffy texture, and the formation of new compounds with different flavors and textures.
7. Melting butter: P (physical change)
Evidence: When butter melts, it undergoes a physical change from a solid to a liquid state. The molecules in the butter rearrange due to an increase in temperature, but the chemical composition of the butter remains the same.