Answer:
2.765amu is the contribution of the X-19 isotope to the weighted average
Explanation:
The average molar mass is defined as the sum of the molar mass of each isotope times its abundance. For the unknown element X that has 2 isotopes the weighted average is defined as:
X = Mass X-19 * Abundance X-19 + MassX-21 * Abundance X-21
The contribution of the X-19 isotope is its mass (19.00 amu) times its abundance (14.55% = 0.1455). That is:
19.00amu * 0.1455 =
2.765amu is the contribution of the X-19 isotope to the weighted average
The mass percentage is 15.1465%.
Yes, you should memorize them. While it is easy to predict them by looking at a periodic table, you should still have a strong grasp of simpler chemistry such as this before more challenging topics are taught.
P=0.0902 g/l
v=22.4 l/mol (stp)
M=vp
M=22.4 l/mol * 0.0902 g/l=2.020 g/mol
M=2.020 g/mol
The mathematical expression for mass percent is given by:
Put the values,
mass of zinc = 
= 
or 65.4 g
Now, number of moles of zinc =
= 
= 1.00 mole
Number of atoms of zinc is calculated by the Avogadro number.
Now, according to mole concept
molecules of enzyme consists of atoms of zinc
So, 1 molecule of enzyme contains =
= 1 atom of zinc.
Hence, every carbonic anhydrase molecule consists of 1 atom of zinc.
