Answer:
The molar mass of the unknown gas is 100.4 g/mol
Explanation:
Step 1: Data given
Molar mass of argon = 39.95 g/mol
After filling with argon the flask gained 3.221 grams
After filling with an unknown gas, the flask gained 8.107 grams
Step 2: Calculate the molar mass of the unknown gas
The gas with the higher molar mass will have the higher density.
Ar - 3.224 g; molar mass = 39.95 g/mol
X = 8.102 g; molar mass = ??
Molar mass of the unknown gas = 8.102g X *(39.95 g/mol / 3.224 g) = 100.4 g/mol
The molar mass of the unknown gas is 100.4 g/mol
One of the best buffer choice for pH = 8.0 is Tris with Ka value of 6.3 x 10^-9.
To support this answer, we first calculate for the pKa value as the negative logarithm of the Ka value:
pKa = -log Ka
For Tris, which is an abbreviation for 2-Amino-2-hydroxymethyl-propane-1,3 -diol and has a Ka value of 6.3 x 10^-9, the pKa is
pKa = -log Ka
= -log (6.3x10^-9)
= 8.2
We know that buffers work best when pH is equal to pKa:
pKa = 8.2 = pH
Therefore Tris would be a best buffer at pH = 8.0.
Pieces of copper, silver and gold are dropped into a solution of iron sulphate. The piece that will get a coating of copper is. ... Therefore, none of the three metals can displace iron from its salt solution. Hence, we observe that no reaction takes place and none of the pieces get coated.
Using the method chromatography