What substance changed physically under all three condition? Copper Wire
What substance changed chemically under all three condition? Steel Wool
What evidence indicates a chemical reaction is occurring? New gases are produced; A phase change has occurred; A color change
Select the three answers that are examples of a chemical reaction. The mixing of an acid and base shows an increase in temperature; after baking bread there is a new odor or smell; when hair is bleached it changes to a lighter color
Which data supports this inference? Baking soda dissolving; A gas formed, creating bubbles
Which experiment best shows evidence of energy being released in a chemical reaction? Heat and light are given off when paper is burned
Which experiment likely resulted in the formation of a precipitate? Two solutions are mixed together and a yellow solid forms
The BEST evidence for a chemical reaction is the formation of a new substance.
Explanation:
2. When heat and light are being given off, energy is being released. Paper burning is a chemical reaction b/c when paper is burnt, it is a new substance and the act can't be undone.
3. When a yellow solid forms, that solid is the participate.
4. You will for sure have a chemical reaction if a new substance is created.
5. Copper wire changed physically b/c the copper wire can be returned to its original condition in all of these situations and no new substance was formed. Steel Wool changed chemically b/c it can't be returned to its original state under any condition and new substances were formed every time.
6. New substances formed indicate a chemical reaction. A color change also is an indication of a chemical reaction.
7. When a substance can't be turned into its original position or a new substance is produced, a chemical reaction occurred.
