Question

question 14 if a box of cacl₂ has a mass of 2.56 g. 0.0231 moles are in the box. 4.17x10^22 atoms are in the box. blank 1 0.0231 blank 2 4.17 blank 3 22

Explanation:

Step1: Identify given values

Mass of $CaCl_2 = 2.56$ g, moles = 0.0231 mol, number of atoms = $4.17\times10^{22}$

Step2: Check moles calculation

Molar mass of $CaCl_2$: $Ca$ has molar - mass 40.08 g/mol, $Cl$ has molar - mass 35.45 g/mol. Molar mass of $CaCl_2=40.08 + 2\times35.45=40.08 + 70.9 = 110.98$ g/mol. Moles of $CaCl_2=\frac{2.56\ g}{110.98\ g/mol}\approx0.0231$ mol.

Step3: Check number of atoms calculation

1 mole of any substance contains $6.022\times10^{23}$ atoms. For 0.0231 moles of $CaCl_2$, number of formula - units of $CaCl_2$ is $n = 0.0231\times6.022\times10^{23}=1.391082\times10^{22}$. But in $CaCl_2$, there are 3 atoms per formula - unit. So number of atoms $=3\times1.391082\times10^{22}=4.173246\times10^{22}\approx4.17\times10^{22}$ atoms.

Answer:

The values in the blanks are correct as they are consistent with the mole - mass and mole - atom relationships for $CaCl_2$.