Which combination is most likely to form a precipitate? A. ammonium hydroxide
B. barium chloride
C. calcium hydroxide
D. calcium acetate
E. iron hydroxide

A - Ammonium Hydroxide (NH3)

Explanation:

• Metals are just too weak

• Calciums' have a low success rate

• Barium is good, but Ammonium is just stronger.

(This is just an opinion, I could definitely be wrong so just do corrections in class. Sorry)

out of these options:

ability to burn paper

pure sodium reacting violently with water

the boiling point of water

helium does not tend to react with anything

i would say this is a physical property:

helium does not tend to react with anything

why? :

i said helium does not tend to react with anything because well, it reacts to ! but ability to burn paper, pure sodium reacting violently with water, & the boiling point of water are chemical or

physical properties: the properties of a substance that can be observed without changing the chemical makeup of the substance

chemical properties: properties of a substance relating to the chemical nature and reactivity of the substance