Answer:
The correct answer is 63.67.
Explanation:
The atomic mass of copper is 63.546 amu
The atomic mass of zinc is 65.38 amu
The weight of total sample is 7.36 grams
Weight of zinc is 0.51 gram
Therefore, weight of copper is 7.36 - 0.51 = 6.85 grams.
By calculating the percent composition we get:
% of copper = 6.85 * 100 / 7.36 = 93.07 %
% of zinc = 100 - 93.07 = 6.93 %
Average atomic mass of sample = (atomic mass of copper * % copper) + (atomic mass of zinc * % of zinc) / 100
= (63.546 * 93.07) + (65.38 * 6.93) / 100
(5914.22 + 453.08) / 100
= 6367.3 / 100 = 63.67
Hence, the measured atomic mass of the sample is 63.67.