Be sure to answer all parts. tris [tris(hydroxymethyl)aminomethane] is a common buffer for studying biological systems. (ka = 5.01 × 10−9 and pka = 8.3) (a) calculate the ph of the tris buffer after mixing 10.0 ml of 0.15 m hcl solution with 25.0 ml of 0.10 m tris. (b) this buffer was used to study an enzyme-catalyzed reaction. as a result of the reaction, 0.00015 mol of h+ was produced. what is the ph of the buffer at the end of the reaction? (c) what would be the final ph if no buffer were present?

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%

in scientific notation, the value of the  speed of light in a vacuum

  will be written as 2.995 * 10^8. when this value is represented in the form of

  a * 10^b, then, a = 2.995 and b = 8.

the value of the speed of light in a vacuum given above can also be rounded up to approximately 300000000. in this case, the scientific notation will be written as 3 *10^8.

distance, luminosity, brightness, radius, chemical composition, and temperature

hey there!

mass = 6.75 g

volume =   9 cm³

therefore:

d = mass / volume

d   = 6.75 / 9

d = 0.7 g/cm³

answer b