Answer:
1. A chemical change that produces a precipitate
Explanation:
A solid substance that is formed from a liquid phase is called a precipitate.
A reaction that produces a precipitate is called a precipitation reaction.
Precipitation reactions are an example of a chemical change.
Thus the correct answer is option 1: A precipitate was formed when vinegar and milk were mixed (as there were no solid substances when they were apart).
1. What kinds of metals are REALLY reactive? why?
2. What kinds of non-metals are REALLY reactive? why?
3. What group on the periodic table doesn’t react at all? why?
Answer:
1. Alkali metals (group 1)
2. halogens (Group 17)
3. noble gasses (group 18)
Explanation:
1. alkali metals only have one valence electron meaning that they really want to lose that one valence electron to get a full octet.
2. halogens have 7 valence electrons meaning that they just need to gain 1 to get a full octet.
3. Nobel gasses already have a full octet meaning that they don't want to react. (atoms only react to get a full octet)
I hope this helps. Let me know if anything is unclear.