How many cations are in 10.0 g of sodium phosphate? A)3)67 × 10²² cations B)1)10 × 10²³ cations C)9)87 × 10²⁴ cations D)2)96 × 10²⁵ cations

Question

Quizplus · Accepted Answer

To find the number of cations in 10.0 g of sodium phosphate, we need to first determine the formula of sodium phosphate, which is Na3PO4. This formula tells us that in each molecule of sodium phosphate, there are 3 sodium cations (Na+) and 1 phosphate anion (PO43-).

Next, we need to use the formula weight of sodium phosphate to determine how many molecules are present in 10.0 g of the compound. The formula weight of Na3PO4 is:

(3 x atomic weight of Na) + atomic weight of P + (4 x atomic weight of O)
= (3 x 22.99 g/mol) + 30.97 g/mol + (4 x 15.99 g/mol)
= 163.94 g/mol

So, 1 mole of Na3PO4 weighs 163.94 g. Using dimensional analysis, we can convert 10.0 g of Na3PO4 to moles:

10.0 g Na3PO4 x (1 mol Na3PO4/163.94 g Na3PO4) = 0.061 mol Na3PO4

Finally, we can use the Avogadro's number (6.022 x 10^23) to convert moles of Na3PO4 to the number of molecules:

0.061 mol Na3PO4 x (6.022 x 10^23 molecules/mol) = 3.67 x 10^22 molecules Na3PO4

Since there are 3 sodium cations in each molecule of Na3PO4, the total number of sodium cations in 10.0 g of sodium phosphate is:

3 x 3.67 x 10^22 molecules Na3PO4 = 1.10 x 10^23 cations

Therefore, the best choice is B, which states that there are 1.10 x 10^23 cations in 10.0 g of sodium phosphate.

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