Final answer:
To calculate the molarity of the given solution, sum the moles of Br₂ and KBr, calculated using their molar masses, and divide by the volume of the solution in liters. Compare the result with the given choices to find the correct molarity.
Step-by-step explanation:
The question asks to determine the molarity of a solution that contains 7.75g of Br₂ and 6.25g of KBr dissolved in 25mL of water. The molarity is a measure of concentration in moles of solute per liter of solution. To solve this, we need to calculate the number of moles of each compound separately using their molar masses and then sum those up to get the total moles of solute. We can calculate this by doing the following:
- Calculate the number of moles of Br₂:
Molar mass of Br₂ = 79.904 g/mol × 2 = 159.808 g/mol
Moles of Br₂ = 7.75g ÷ 159.808 g/mol - Calculate the number of moles of KBr:
Molar mass of KBr = 119.0 g/mol
Moles of KBr = 6.25g ÷ 119.0 g/mol - Sum the moles of Br₂ and KBr to get total moles.
Total moles = Moles of Br₂ + Moles of KBr - Convert 25mL to liters (0.025 L) because molarity is moles/L.
Molarity (M) = Total moles ÷ 0.025 L
After calculating these steps, you would find the molarity that matches one of the given choices (a) 0.1 M, (b) 0.5 M, (c) 1.0 M, or (d) 2.0 M.