Answer:
39.02
Step-by-step explanation:
From the question given above, the following data were obtained:
Isotope A:
Mass of A = 38
Abundance of A (A%) = 9.67%
Isotope B:
Mass of B = 39
Abundance of B (B%) = 78.68%
Isotope C:
Mass of C = 40
Abundance of C (C%) = 11.34%
Isotope D:
Mass of D = 41
Abundance of D (D%) = 0.31%
Average atomic mass of X =?
The average atomic mass of X can be obtained as follow:
Average = [(Mass of A × A%)/100] + [(Mass of B × B%)/100] + [(Mass of C × C%)/100] + [(Mass of D × D%)/100]
= [(38 × 9.67)/100] + [(39 × 78.68)/100] + [(40 × 11.34)/100] + [(41 × 0.31)/100]
= 3.6746 + 30.6852 + 4.536 + 0.1271
= 30.02
Thus, the average atomic mass of X is 39.02