How many moles are represented by 9.34 x 1021 sodium atoms a. 1.25x10^2 moles

b. 1.55x10^3 moles

c. 1.55x10^2 moles

d. 1.55 moles

1.55×10⁻² moles of sodium

Explanation:

Given data:

Number of atoms of sodium = 9.34×10²¹ atoms

Number of moles of sodium = ?

Solution:

Avogadro number:  

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.  The number 6.022 × 10²³ is called Avogadro number.

1 mole = 6.022 × 10²³ atoms

9.34×10²¹ atoms × 1 mol / 6.022 × 10²³ atoms

1.55×10⁻² mol

when [oh-] is 10-5  m, and [h3o+] is 10-9  m, the poh is 5 and ph is 9. again in both cases the sum of ph and poh is 14. however, the hydrogen ion concentration is not always going to be equal to exactly 1 x 10 raised to a negative number. for example, we skipped over the value of 2.0 x 10-7.