Question

question 9 (1 point)
use the molar mass of ( ca_3(po_3)_2 ) to calculate the number of formula units in 10.0 g of cp. choose the closest answer.
( (10.0 g cp)(---------) = 1mol cp(---------) = 2fu )
a. ( 1.11\times10^{10} ) b. ( 3.98\times10^{3} ) c. ( 2.39\times10^{4} ) d. 0.360 e. 2.90
f. ( 2.16\times10^{22} ) g. 0.345 h. ( 1.68\times10^{25} ) i. ( 1.85\times10^{9} ) j. 34.5
k. ( 1.44\times10^{5} ) l. ( 2.78\times10^{3} ) m. ( 4.00\times10^{7} ) n. ( 5.97\times10^{-26} )
o. ( 5.97\times10^{26} ) p. ( 3.60\times10^{-2} ) q. ( 2.78\times10^{-3} )

Explanation:

Step1: Calculate the molar mass of \(Ca_3(PO_3)_2\)

The molar mass of \(Ca = 40.08\space g/mol\), \(P = 30.97\space g/mol\), \(O = 16.00\space g/mol\).

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Step2: Calculate the number of moles of \(Ca_3(PO_3)_2\)

Using the formula \(n=\frac{m}{M}\), where \(m = 10.0\space g\) and \(M = 278.18\space g/mol\)

$$n=\frac{10.0}{278.18}\approx0.0360\space mol$$

Step3: Calculate the number of formula units

Using the formula \(N = n\times N_A\), where \(N_A=6.022\times 10^{23}\space mol^{-1}\)

$$N=0.0360\times6.022\times 10^{23}=2.16792\times 10^{22}$$

Answer:

1. \(0.0360\) (corresponds to option P)
2. \(2.16\times 10^{22}\) (corresponds to option F)