Question

What is the mass in grams of a single formula unit of silver chloride, AgCI? A) 4.21 x 1021 g B) 8.61 x 10258 C) 1.66 x 10-248 D) 2.38 x 10-228 E) 1.16 x 10-26

Answer 1

Answer : The mass in grams of a single formula unit of silver chloride will be
`2.38* 10^(-22)g`

Step-by-step explanation:

Formula units : It is defined as lowest whole number ratio of ions in an ionic compound. It is calculate by multiplying the number of moles by Avogadro's number which is
`6.022* 10^(23)`.

Single formula unit of silver chloride means that 1 mole of silver chloride.

We are given :

Number of moles of silver chloride = 1 moles

The molar mass of silver chloride = 143.32 g/mole

That means, 1 mole silver chloride contains 143.32 grams of silver chloride.

Now we have to determine the mass in grams of a single formula unit of silver chloride.

As,
`6.022* 10^(23)` formula unit has mass = 143.32 g

So, 1 formula unit has mass =
`(1)/(6.022* 10^(23))* 143.32=2.38* 10^(-22)g`

Therefore, the mass in grams of a single formula unit of silver chloride will be
`2.38* 10^(-22)g`

Answer 2

Answer: D)
`2.38*10^-^2^2` g

Explanation: The question asks to convert formula unit to grams. It is a unit conversion problem.

1 mole equals to Avogadro number of formula units. So, to convert the given number of formula units to moles, we need to divide by the Avogadro number. After this, we do moles to grams conversion and for this the moles are multiplied by the molar mass of the compound. Molar mass of AgCl is 143.32 gram per mol.

`1FormulaUnitAgCl((1mol)/(6.022*10^2^3formulaUnits))((143.32g)/(1mol))`

=
`2.38*10^-^2^2` g

So, the correct option is D)
`2.38*10^-^2^2` g