78 g of potassium (K) react with 71 g of chlorine (Cl) to produce potassium chloride. According to the Law of Conservation of Mass, what is the mass of the product (2KCl)
(1 point)
Responses
149 g
156 g
2 g
4 g
According to the Law of Conservation of Mass, the mass of the product (2KCl) would be equal to the total mass of the reactants.
The total mass of the reactants is 78 g + 71 g = 149 g.
Therefore, the correct answer is 149 g.
To determine the mass of the product (2KCl), we first need to find the molar masses of potassium (K) and chlorine (Cl).
The molar mass of potassium (K) is approximately 39.10 g/mol.
The molar mass of chlorine (Cl) is approximately 35.45 g/mol.
Next, we calculate the number of moles for each element.
Moles of K = mass of K / molar mass of K
= 78 g / 39.10 g/mol
= 1.998 mol (approximately 2 mol)
Moles of Cl = mass of Cl / molar mass of Cl
= 71 g / 35.45 g/mol
= 2.003 mol (approximately 2 mol)
Since the balanced chemical equation shows that 2 moles of K react with 1 mol of Cl to produce 2 moles of KCl, we can conclude that the limiting reactant is K (since there is not enough Cl to react with all of the K).
Therefore, the number of moles of KCl produced is equal to the number of moles of K reacted, which is 2 mol.
Finally, we calculate the mass of 2KCl.
Mass of 2KCl = molar mass of KCl x 2 mol
= (39.10 g/mol + 35.45 g/mol) x 2 mol
= 74.55 g/mol x 2 mol
= 149.10 g
Therefore, the mass of the product (2KCl) is approximately 149 g.
So, the correct answer is:
149 g
To find the mass of the product (2KCl), we need to first calculate the molar mass of potassium chloride (KCl).
The molar mass of potassium (K) is approximately 39.10 g/mol, and the molar mass of chlorine (Cl) is approximately 35.45 g/mol.
Since there are two potassium atoms and two chlorine atoms in the product (2KCl), we can calculate the molar mass of potassium chloride:
Molar mass of KCl = 2 * (molar mass of K) + 2 * (molar mass of Cl)
= 2 * 39.10 g/mol + 2 * 35.45 g/mol
= 78.20 g/mol + 70.90 g/mol
= 149.10 g/mol
According to the Law of Conservation of Mass, the mass of the product should be equal to the combined mass of the reactants.
Given that 78 g of potassium (K) and 71 g of chlorine (Cl) are used in the reaction, the total mass of the reactants is 78 g + 71 g = 149 g.
Therefore, the correct answer is 149 g.