Answer:
1.71 × 10²¹ molecules
Explanation:
1 gram is equal to 1000 milligrams. The mass in grams corresponding to 500 mg is:
500 mg × (1 g / 1000 mg) = 0.500 g
The molar mass of ascorbic acid is 176.12 g/mol. The moles corresponding to 0.500 grams of ascorbic acid are:
0.500 g × (1 mol/ 176.12 g) = 0.00284 mol
In 1 mole of ascorbic acid, there are 6.02 × 10²³ molecules of ascorbic acid (Avogadro's number). The molecules in 0.00284 moles are:
0.00284 mol × (6.02 × 10²³ molecules/ 1 mol) = 1.71 × 10²¹ molecule
I think the awnser to your question is C
<u>Answer:</u> The fugacity coefficient of a gaseous species is 1.25
<u>Explanation:</u>
Fugacity coefficient is defined as the ratio of fugacity and the partial pressure of the gas. It is expressed as 
Mathematically,

Partial pressure of the gas is expressed as:

Putting this expression is above equation, we get:

where,
= fugacity coefficient of the gas
= fugacity of the gas = 25 psia
= mole fraction of the gas = 0.4
P = total pressure = 50 psia
Putting values in above equation, we get:

Hence, the fugacity coefficient of a gaseous species is 1.25
The molality is calculated using the following rule:
molality = number of moles of solute / kg of solvent
From the periodic table:
molar mass of lithium = 6.941 gm
molar mass of chlorine = 35.453 gm
molar mass of LiCl = 6.941 + 35.453 = 42.394 gm
number of moles found in 42 gm = mass / molar mass = 42 / 42.394 = 0.99
molality = 0.99 / 3.6 = 0.275 m