Answer:
1.38 kg
Explanation:
Pre-Solving
We are given a 1.15 M solution of sucrose. There is 3.50 L of this solution.
We want to find how many kilograms of sucrose is needed to make 3.50 L of 1.15 M solution.
Recall that molarity is moles / L.
Solving
First, we need to find how many moles of sucrose we have. We can calculate it using the number of liters we have:
[tex]3.50 L * \frac{1.15 mole}{1 L} = 4.025 moles[/tex] (let's worry about sig figs at the end - make a mental note that the answer should have 3 sig figs).
Now, convert from moles to grams. The molar mass of sucrose is 342.30 g/mol. So:
[tex]4.025 moles * \frac{342.30g}{1 mol} = 1377.7575 g[/tex]
Now, convert from grams to kilograms:
[tex]1377.7575 g * \frac{1 kg}{1000g} = 1.38 kg[/tex] (rounded to 3 sig figs).
