A chemical change affects on the molecular level of matter, which makes it irreversible. Combustion is a pretty good exmple. Physical changes are reversible and dont alter the formula. Hope this helped!
Complete Question
The complete question is shown on the first uploaded image
Answer:
The bond angle is 104.48⁰
Explanation:
The explanation is shown on the second uploaded image
The reaction will produce 12.1 g Ag₂S.
<em>Balanced equation</em> = 2Ag + S ⟶ Ag₂S
<em>Mass of Ag₂S</em> = 10.5 g Ag × (1 mol Ag/107.87 g Ag) × (1 mol Ag₂S/2 mol Ag)
× (247.80 g Ag₂S/1 mol Ag₂S) = 12.1 g Ag₂S
<span>Assuming that there are 36 strontium and 24 phosphate, there
aren’t any equal cations and anoins because in theory only one ionic bond is
formed by a strontium with each phosphate ion. To the point that a cation will
eventually have an excess.</span>
