Yes, the darkening of a copper penny is a chemical change. When copper is exposed to air and moisture, it reacts with oxygen and carbon dioxide, leading to the formation of copper oxide and other compounds that give the penny a darker appearance. This process alters the chemical composition of the copper, indicating a chemical change rather than a physical one.
To my knowledge, a penny is not a chemical change. No, I think it is instead a coin; a unit of currency, mostly made from zinc and plated with copper. Nothing I'm describing has anything to do with chemical changes.
Cleaning a penny with vinegar and salt is a chemical change. The vinegar (acetic acid) reacts with the salt (sodium chloride) to form a chemical compound that removes the tarnish on the copper surface of the penny. This reaction changes the composition of the penny's surface, making it appear shiny and clean.
If you use a abrasive to scrape the rust off, then it is a physical change. If you utilize a chemical that combines with the rust leaving the unoxidized penny behind, then it is a chemical change.
To my knowledge, a penny is not a chemical change. No, I think it is instead a coin; a unit of currency, mostly made from zinc and plated with copper. Nothing I'm describing has anything to do with chemical changes.
No, the green color on a penny comes from oxidation of the copper in the coin, while the Statue of Liberty turned green due to the natural weathering of the copper material it is made of over time. Different mechanisms are at play in these two situations.
Chemical.
Putting a penny in lemon juice would cause a chemical change because the lemon juice reacts with the copper in the penny to create copper oxide, which changes the chemical composition of the penny.
Corroding
To my knowledge, a penny is not a chemical change. No, I think it is instead a coin; a unit of currency, mostly made from zinc and plated with copper. Nothing I'm describing has anything to do with chemical changes.
Yes. Dissolution of a copper penny would indeed be a chemical reaction.
You can also turn pennies and some other coins green by letting them sit overnight in a paper towel soaked in vinegar. and if you want to clan pennies to shine, put them in a cup of vinegar and salt dissolved. (I once tried cleaning them with a pinch of kosher salt instead and it dug a hole through the penny! -NOT RECOMENDED!!!)
Cleaning a penny with vinegar and salt is a chemical change. The vinegar (acetic acid) reacts with the salt (sodium chloride) to form a chemical compound that removes the tarnish on the copper surface of the penny. This reaction changes the composition of the penny's surface, making it appear shiny and clean.
If you use a abrasive to scrape the rust off, then it is a physical change. If you utilize a chemical that combines with the rust leaving the unoxidized penny behind, then it is a chemical change.
Coke or sprite will change the color of a penny.
To my knowledge, a penny is not a chemical change. No, I think it is instead a coin; a unit of currency, mostly made from zinc and plated with copper. Nothing I'm describing has anything to do with chemical changes.
Turning a penny gold is a physical reaction rather than a chemical reaction. This process involves coating the penny with a layer of gold, which changes its appearance but does not alter the chemical composition of the penny itself.
A penny can turn silver due to a chemical reaction with substances like vinegar or lemon juice, which react with the copper in the penny to form copper oxide. Copper oxide has a silver color, leading to the appearance of the penny turning silver.