Use avogadro's number---> 6.02 x 10^23 atoms= 1 mol
7.81 x 10^21 (1 mole/ 6.02 x 10^23)= 0.0130 moles of Cu
Answer:
A. 0.295 mole
B. 0.055 mole
C.0.144 mole
D. 0.03 mole
Explanation:
To find the amount in moles, we simply use a mathematical relation that connects mass, atomic mass and number of moles.
Number of moles = mass/atomic mass
A. Atomic mass of Argon is 40
n = 11.8/40 = 0.295 mole
B. Atomic mass of zinc is 65
n = 3.55/65 = 0.055 mole
C. Atomic mass of Tantalum is 181
n = 26.1/181 = 0.144 mole
D. Atomic mass of lithium is 7
n = 0.211/7 = 0.03 mole
