A chemistry graduate student is given 300. mL of a 0.20 M ammonia (NH_3) solution. Ammonia is a weak base with K_b = 1.8 times 10^-5. What mass of NH_4 Br should the student dissolve in the NH3 solution to turn it into a buffer with pH = 9.10? You may assume that the volume of the solution doesn't change when the NH4Br is dissolved in it. Be sure your answer has a unit symbol, and round it to 2 significant digits.

Two things that biomedical has invented or innvated

Which explanation is true about what happens to a ray of light when it strikes a mirror? a. a light ray is transmitted toward a mirror at a certain angle. the light ray is then reflected by the mirror at an equal angle but in the opposite direction of the transmitted ray. b. an incident ray strikes a mirror at an angle with a line perpendicular to the mirror. the light ray is then reflected at an angle equal to the angle of incidence but on the opposite side of the perpendicular line. c. a reflecting ray strikes a mirror at an angle with a line perpendicular to the mirror. the light ray is then refracted at an angle equal to the angle of the reflecting ray and on the same side of the perpendicular line. d. an incident ray strikes a mirror at an angle with a line parallel to the mirror. the light ray is then transmitted at an angle equal to the angle of incidence but on the opposite side of the parallel line. you so much! : -d take the time to try and answer correctly.

What is the ph of a 0.0010 m hno3? 1.0 3.0 4.0 5.0