If 0.670mol of liquid Br2 and 460mL of 1.72M aqueous NaI are reacted stoichiometrically according to the balanced equation, how many moles of liquid Br2 remain? Round answer to 3 sig figs.
2NaI(aq) + Br2(l) -> 2NaBr(aq) + I2(s)
Additional Information:
MM of Br2 = 159.81 g/mol
MM of NaI = 149.89 g/mol
Density of Br2 = 3.12g/mL
Molar Volume = 22.4L at STP
Gas Constant = 0.0821
This is a limiting reagent problem.
Determine moles Br2. You have that in the problem. Determine moles NaI from moles = M x L. Look at the equation. It will taake twice as much NaI to react so if you have twice as much NaI as Br2, then Br2 will be the limiting reagent and you will have NaI remain. From the way the problem is stated, I assume NaI is the limiting reagent and Br2 will remain. You can tell from the moles of each. Post your work if you get stuck.
To determine how many moles of liquid Br2 remain after the reaction, we need to calculate the moles of Br2 initially reacted and compare it to the moles of Br2 that are consumed in the reaction.
First, we need to calculate the moles of Br2 initially reacted. We are given the volume of liquid Br2 and its density, so we can calculate its mass using the formula:
mass = volume × density
The volume of liquid Br2 is given as 0.670 mol. Since the density of Br2 is given as 3.12 g/mL, we can convert the volume from mL to grams:
mass = 0.670 mol × 3.12 g/mL × 460 mL
mass ≈ 932.0448 g
Next, we can convert the mass of Br2 to moles using its molar mass:
moles of Br2 = mass / molar mass
moles of Br2 = 932.0448 g / 159.81 g/mol
moles of Br2 ≈ 5.8209 mol
So, initially, there are approximately 5.821 moles of liquid Br2 reacted.
According to the balanced equation, we can see that the stoichiometry is 1:1 between Br2 and NaI. This means that for every mole of Br2 reacted, one mole of Br2 is consumed.
Therefore, the moles of Br2 that remain after the reaction are:
moles of Br2 remaining = moles of Br2 initially reacted - moles of Br2 consumed
moles of Br2 remaining = 5.821 mol - 5.8209 mol
moles of Br2 remaining ≈ 0.0001 mol
Rounding this answer to 3 significant figures, we find that approximately 0.000 mol of liquid Br2 remains after the reaction.