I need help with number 17 pls someone pls ???

can you pls say what subject it is pls and thank u

Explanation:

glass cup as it can trap oxygen from getting in and out meaning that the fire can't grow

convalent bond :

is a chemical bond formed by the sharing of electron between 2 atoms.

it is the direct chemical bond between 2 atoms.

in bond formation atoms are involved here.

electrovalent bond:

is a chemical bond defined as electroststic attraction between 2 atoms.

it is the electrostatic attraction between 2 atoms.

in bond formation, ions are involved here.

hope it

and ur welcm

: )

answers: to make sure that all of the broken pieces of tablet were added to the water, to allow for fair comparison of all three trials, with different particle sizes to avoid experimental error