Question

How many atoms are in 3.2 pg of Ca? The molar mass of Ca is 40.08 g/mol.

Answer 1

Answer:

4.81×10¹⁰ atoms.

Explanation:

We'll begin by converting 3.2 pg to Ca to grams (g). This can be obtained as follow:

1 pg = 1×10¯¹² g

Therefore,

3.2 pg = 3.2 pg × 1×10¯¹² g / 1 pg

3.2 pg = 3.2×10¯¹² g

Therefore, 3.2 pg is equivalent to 3.2×10¯¹² g

Next, we shall determine the number of mole in 3.2×10¯¹² g of Ca. This can be obtained as follow:

Mass of Ca = 3.2×10¯¹² g

Molar mass of Ca = 40.08 g/mol

Mole of ca=.?

Mole = mass /molar mass

Mole of Ca = 3.2×10¯¹² / 40.08

Mole of Ca = 7.98×10¯¹⁴ mole.

Finally, we shall determine the number of atoms present in 7.98×10¯¹⁴ mole of Ca. This can be obtained as illustrated below:

From Avogadro's hypothesis,

1 mole of Ca contains 6.02×10²³ atoms.

Therefore, 7.98×10¯¹⁴ mole of Ca will contain = 7.98×10¯¹⁴ × 6.02×10²³ = 4.81×10¹⁰ atoms.

Therefore, 3.2 pg of Ca contains 4.81×10¹⁰ atoms.