We wish to determine the mass of [tex]BaSO_4[/tex] formed when [tex]200 \, \text{mL}[/tex] of [tex]0.10 \, \text{M} \, BaCl_2[/tex] reacts with excess [tex]Na_2SO_4[/tex] according to the equation below.

[tex]\[BaCl_2(aq) + Na_2SO_4(aq) \rightarrow BaSO_4(s) + 2NaCl(aq)\][/tex]

How many moles of [tex]BaCl_2[/tex] are present in [tex]200 \, \text{mL}[/tex] of [tex]0.10 \, \text{M} \, BaCl_2[/tex]?



Answer :

To solve the problem, we need to determine the number of moles of [tex]\( \text{BaCl}_2 \)[/tex] present in a [tex]\( 200 \, \text{mL} \)[/tex] solution of [tex]\( 0.10 \, \text{M} \text{BaCl}_2 \)[/tex].

Let's go through the calculations step-by-step:

1. Convert Volume to Liters:
The volume given is [tex]\( 200 \, \text{mL} \)[/tex]. We need to convert this volume from milliliters (mL) to liters (L) because molarity (M) is defined in terms of liters.
[tex]\[ \text{Volume of } \text{BaCl}_2 \text{ solution} = 200 \, \text{mL} = \frac{200}{1000} \, \text{L} = 0.2 \, \text{L} \][/tex]

2. Calculate Moles of [tex]\(\text{BaCl}_2\)[/tex]:
Molarity (M) is defined as the number of moles of solute per liter of solution. Therefore, to find the moles of [tex]\( \text{BaCl}_2 \)[/tex], we use the formula:
[tex]\[ \text{Moles of } \text{BaCl}_2 = \text{Molarity} \times \text{Volume (in L)} \][/tex]
Given the molarity of [tex]\( \text{BaCl}_2 \)[/tex] is [tex]\( 0.10 \, \text{M} \)[/tex]:
[tex]\[ \text{Moles of } \text{BaCl}_2 = 0.10 \, \text{M} \times 0.2 \, \text{L} = 0.02 \, \text{moles} \][/tex]

Therefore, there are [tex]\( 0.02 \)[/tex] moles of [tex]\(\text{BaCl}_2\)[/tex] present in [tex]\( 200 \, \text{mL} \)[/tex] of [tex]\( 0.10 \, \text{M} \text{BaCl}_2\)[/tex].