6.
(3) I, III
Which of the following has the largest number of
atoms?
(1) 0.5 g atom of Cu
(3) 0.623 g of Cu
(2) 1023 atoms of Cu
(4) 3.175 g of Cu
Answers
Explanation:
Complete step by step solution:
We know, the molar mass of Cu is 63.5g
I.e. 63.5g of copper contains Avogadro’s number (
N
A
NA) atoms of copper
∴
∴
63.5g copper=
6.023×
10
23
6.023×1023
atoms of copper.
So, following unitary method, we get-
0.635g of copper=
(6.023×
10
23×0.635)÷63.5
(6.023×1023×0.635)÷63.5
atoms of copper=
6.023×
10
21
6.023×1021
atoms of copper
Similarly, for 1g of copper we have,
1g of copper=
(6.023×
10
23×1)÷63.5
(6.023×1023×1)÷63.5
=
9.485×
10
21
9.485×1021
atoms of copper
For 0.5g atom of Cu,
Number of atoms=
0.5×6.022×
10
23
0.5×6.022×1023
=
3.011×
10
23
3.011×1023
atoms of copper
Now, for 0.25 moles of copper,
∵
∵
1 mole of copper=
6.023×
10
23
6.023×1023
atoms of copper
∴
∴
0.25 moles of copper=
0.25×6.023×
10
23
0.25×6.023×1023
=
1.50575×
10
23
1.50575×1023
atoms of copper.
From the above calculations it is clear that 0.5g atom of Copper has the highest number of atoms present.
Therefore, option [A] 0.5g atom of Cu atom is the correct answer.