To calculate the percent by mass of NaCl in the mixture, you need to follow the steps outlined in the problem. Here's how you can do it step by step:
Step 1: Determine the mass of AgCl formed
Given that 1.913g of AgCl is formed, use the molar mass of AgCl (143g/mol) to calculate the number of moles:
moles of AgCl = mass of AgCl / molar mass of AgCl
moles of AgCl = 1.913g / 143g/mol
moles of AgCl = 0.01336 mol
Step 2: Determine the number of moles of NaCl and NaNO3
Let's assume the mass of NaCl in the mixture is x grams. Then, the mass of NaNO3 in the mixture would be (0.887g - x) grams.
Calculate the number of moles for each compound using their respective molar masses (NaCl: 58g/mol, NaNO3: 85g/mol):
moles of NaCl = mass of NaCl / molar mass of NaCl
moles of NaCl = x g / 58g/mol
moles of NaNO3 = mass of NaNO3 / molar mass of NaNO3
moles of NaNO3 = (0.887g - x) g / 85g/mol
Step 3: Use stoichiometry to equate moles of AgCl and NaCl
Since AgNO3 reacts with NaCl to form AgCl, you can set up a balanced equation:
AgNO3 + NaCl -> AgCl + NaNO3
The stoichiometric ratio between AgCl and NaCl is 1:1.
So, the moles of AgCl formed should be equal to the moles of NaCl:
0.01336 mol = moles of NaCl = moles of NaNO3
Step 4: Solve for x to find the mass of NaCl
Since the moles of NaCl and NaNO3 are equal, you can create an equation and solve for x:
moles of NaCl = x g / 58g/mol = 0.01336 mol
x g = 0.01336 mol * 58g/mol
x g = 0.7739 g
Step 5: Calculate the percent by mass of NaCl in the mixture
The percent by mass is given by:
percent by mass = (mass of NaCl / total mass of the mixture) * 100
percent by mass = (0.7739 g / 0.8870 g) * 100
percent by mass = 87.13 %
Therefore, the percent by mass of NaCl in the mixture is approximately 87.13%.
Note: The answer you provided (87.87%) may be due to rounding errors in the calculations.