If 2.00 grams of potassium are allowed to react with 2.00 grams of bromine by the following equation, which reactant is the limiting reactant?

2K + Br2 ==> 2KBr

mols K = 2/atomic mass K = about 0.05
mols Br2 = 2/molar mass Br2 = about 0.012
Convert mols K to mols Br2. That's about 0.05 x (1 mol Br2/2 mols K) = about 0.05 x 1/2 = about 0.025. Do you have that many mols Br2? NO, so Br2 is the limiting reagent.

To determine the limiting reactant, we need to compare the moles of each reactant and see which one is present in a lesser amount. Let's calculate the moles of potassium (K) and bromine (Br2) using their respective masses and molar masses.

1. Start by finding the molar masses of potassium and bromine:
- Molar mass of potassium (K) = 39.10 g/mol
- Molar mass of bromine (Br2) = 79.90 g/mol

2. Next, calculate the moles of each reactant. Recall that moles can be calculated by dividing the mass of a substance by its molar mass.

Moles of potassium (K):
Moles = Mass / Molar mass
Moles of K = 2.00 g / 39.10 g/mol

Moles of bromine (Br2):
Moles = Mass / Molar mass
Moles of Br2 = 2.00 g / 79.90 g/mol

3. Calculate the moles of each reactant:
Moles of K = 0.051 mol
Moles of Br2 = 0.025 mol

Now that we have calculated the moles of each reactant, we can see that potassium (K) is present in a higher amount (0.051 mol) compared to bromine (Br2) (0.025 mol). The reactant with the lower amount of moles is the limiting reactant. Therefore, in this case, the limiting reactant is bromine (Br2).

To determine the limiting reactant, we need to compare the amount of product that can be formed from each reactant.

The balanced equation for the reaction between potassium (K) and bromine (Br2) is:

2K + Br2 -> 2KBr

To find the limiting reactant, we need to calculate the number of moles for each reactant.

First, let's find the number of moles for potassium (K):

Given mass of potassium = 2.00 grams
Molar mass of potassium (K) = 39.10 g/mol

Number of moles of potassium = Mass of potassium / Molar mass of potassium
Number of moles of potassium = 2.00 g / 39.10 g/mol
Number of moles of potassium = 0.051 mol

Now, let's find the number of moles for bromine (Br2):

Given mass of bromine = 2.00 grams
Molar mass of bromine (Br2) = 79.90 g/mol

Number of moles of bromine = Mass of bromine / Molar mass of bromine
Number of moles of bromine = 2.00 g / 79.90 g/mol
Number of moles of bromine = 0.025 mol

Considering the balanced equation, we can see that 2 moles of potassium react with 1 mole of bromine.

Comparing the number of moles of each reactant, we have:
Potassium: 0.051 mol
Bromine: 0.025 mol

Since we need 2 moles of potassium to react with 1 mole of bromine, the limiting reactant would be bromine, as there is less moles of bromine available compared to the required amount for the reaction.