What is the atomic weight of an element if 4.00 grams of it contain
Atoms?
A)20.2 u
B)80.8 u
C)19.7 u
D)8.08 u
E)2.02 u

Question

What is the atomic weight of an element if 4.00 grams of it contain 
Atoms?
A)20.2 u 
B)80.8 u 
C)19.7 u 
D)8.08 u 
E)2.02 u

Quizplus · Accepted Answer

The atomic weight of an element is the average mass of an atom of that element, taking into account all its isotopes. We can calculate the atomic weight of the element using the following formula:

Atomic weight = (mass of sample ÷ number of atoms) × Avogadro's number

In this problem, we are given the mass of the sample (4.00 grams) and the number of atoms (11.3 x 10^23 atoms). We know that Avogadro's number is 6.02 x 10^23 atoms per mole.

So, plugging in the values we get:

Atomic weight = (4.00 g ÷ 11.3 x 10^23) × 6.02 x 10^23 = 80.8 u

Therefore, the best choice is B.

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