Answer:
Reflection: you look in the mirror. Refraction: You put a straw in a glass of water, and it looks like it broke. Absorption: If you have a black sweater and you wear it out in the cold, the black sweater is going to hold in heat better than a lighter sweater because the black sweater absorbs light .
Moles Ag = 68.3 g / 107.868 g/mol=0.633
Answer: pH = 2.68
Explanation: pH = - log[H3O^+] .
HCl reacts with water : HCl + H2O -> Cl^- + H3O^+
So [H3O^+] = c(HCl) = 0.0021 M
pH = - log(0.0021) = 2.68
PH indicators detect the presence of H+ and OH-. They do this by reacting with H+ and OH-: they are themselves weak acids and bases. If an indicator is a weak acid and is coloured and its conjugate base has a different colour, deprotonation causes a colour change.
What you have to do is 4/5 * 7/8 and that's your answer