Chemical and physical changes.
please could someone help me i need to say whether the following are chemical or physical changes and explain why. I`ve looked myself but i can`t find anything that helps. grateful for any help .thanks
Frying an egg , burning paper , mixing a cake ,whisking an egg , digesting food , puddle drying up,rusting metal , breaking a bottle
Just remember that with a PHYSICAL change the chemical make up of the item remains the same; it changes it's looks but is the same chemically.
When CHEMICAL changes occur, then the make up changes as well.
For example when ice melts, the ice is now water but the chemical make up remains the same - thus PHYSICAL change
But when milk becomes "sour", then it's not the exact same milk anymore - it has added substances that caused the milk to sour - thus, it's a CHEMICAL change.
Since this is not my area of expertise, I searched Google under the key words "chemical physical change" to get these possible sources:
http://www.physlink.com/Education/AskExperts/ae244.cfm
http://www.chem4kids.com/files/matter_chemphys.html
http://www.teacherbridge.org/public/bhs/teachers/Dana/chemphys.html
http://www.fordhamprep.org/gcurran/sho/sho/lessons/lesson15.htm
http://www.mcwdn.org/chemist/pcchange.html
In the future, you can find the information you desire more quickly, if you use appropriate key words to do your own search. Also see http://hanlib.sou.edu/searchtools/.
I hope this helps. Thanks for asking.
what is the scintific name for rainbow
its albert not nikola tesla
Sure, I'd be happy to help you determine whether each of the following processes is a chemical or a physical change and explain why.
1. Frying an egg: Chemical change. When you fry an egg, the proteins in the egg undergo a chemical reaction, known as denaturation, which involves the breaking and reforming of chemical bonds. The liquid egg turns into a solid due to this reaction, which is why it's considered a chemical change.
2. Burning paper: Chemical change. When paper burns, it reacts with oxygen in the air and undergoes a combustion reaction. The paper breaks down and forms new substances, such as carbon dioxide, water vapor, and ash. This transformation is a chemical change.
3. Mixing a cake: Physical change. Mixing a cake involves combining dry and wet ingredients together, but it does not change the chemical composition of the ingredients. The ingredients retain their original properties, so this is considered a physical change.
4. Whisking an egg: Physical change. Whisking an egg involves physically blending the egg white and yolk together. During this process, the physical properties of the egg, such as its texture and consistency, change, but its chemical composition remains the same. This is why whisking is classified as a physical change.
5. Digesting food: Chemical change. Digestion is a complex process that occurs in our bodies where the food we consume breaks down through a series of chemical reactions. Enzymes and acids in our digestive system break down the food into smaller molecules that can be absorbed by the body. Since the chemical composition of the food changes during digestion, it is considered a chemical change.
6. Puddle drying up: Physical change. When a puddle dries up, the water undergoes a physical change. It evaporates, converting from a liquid state to a gas state without a change in its chemical composition. The puddle is no longer present, but the water molecules still remain in the environment, just in a different form.
7. Rusting metal: Chemical change. Rusting occurs when iron or metal alloys come into contact with oxygen and water. This reaction leads to the formation of iron oxide (rust). The chemical composition of the metal changes during this process, making rusting a chemical change.
8. Breaking a bottle: Physical change. Breaking a bottle involves the physical shattering of glass but does not alter the chemical composition of the glass. The broken pieces retain their original properties, indicating a physical change.
Remember that determining whether a change is chemical or physical often requires an understanding of the changes happening at the molecular level.