Question
- A chemist carries out an experiment to determine the number of moles of
ions in a 1 L sample of
water. The salt water reacts with excess
solution. The resulting precipitate is collected, dried
and weighed. The mass of the AgCl precipitate is found to be 5.4 g . The chemical equation for the
reaction is:
Calculate the moles of
ions in the sample, and describe how the number of moles was found. Re
to the periodic table.
water. The salt water reacts with excess
and weighed. The mass of the AgCl precipitate is found to be 5.4 g . The chemical equation for the
reaction is:
to the periodic table.
Ask by Ramirez Wang. in the United States
Mar 11,2025
Upstudy AI Solution
Tutor-Verified Answer
Answer
The number of moles of
ions in the sample is approximately 0.0377 moles.
Solution
To calculate the moles of
ions in the sample, we need to use the chemical equation provided and the mass of the AgCl precipitate.
Given:
- Mass of AgCl precipitate = 5.4 g
- Chemical equation:
First, we need to find the molar mass of AgCl. The molar mass of AgCl can be calculated by adding the atomic masses of Ag and Cl.
The atomic mass of Ag is 107.868 g/mol, and the atomic mass of Cl is 35.453 g/mol.
Molar mass of AgCl = 107.868 g/mol + 35.453 g/mol = 143.321 g/mol
Next, we can calculate the number of moles of AgCl precipitate using the mass of the precipitate and the molar mass of AgCl.
Number of moles of AgCl = Mass of AgCl precipitate / Molar mass of AgCl
Number of moles of AgCl = 5.4 g / 143.321 g/mol
Now, we need to find the number of moles of
ions in the sample. Since the chemical equation shows that 1 mole of AgCl is formed from 1 mole of
ions, the number of moles of
ions is equal to the number of moles of AgCl.
Therefore, the number of moles of
ions in the sample is 5.4 g / 143.321 g/mol.
Let’s calculate this.
Calculate the value by following steps:
Calculate the value by following steps:
- step0: Calculate:
- step1: Convert the expressions:
- step2: Multiply by the reciprocal:
- step3: Reduce the numbers:
- step4: Multiply:
- step5: Multiply:
The number of moles ofions in the sample is approximately 0.037678 moles.
To find the number of moles of
ions, we first calculated the number of moles of AgCl precipitate using the mass of the precipitate and the molar mass of AgCl. Since the chemical equation shows that 1 mole of AgCl is formed from 1 mole of
ions, the number of moles of
ions is equal to the number of moles of AgCl. Therefore, the number of moles of
ions in the sample is approximately 0.037678 moles.
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The Deep Dive
To find the moles of
ions in the sample, we first need to determine the number of moles of the precipitate
. The molar mass of
is approximately 143.32 g/mol (with silver
being about 107.87 g/mol and chlorine
being about 35.45 g/mol).
Using the mass of
precipitate, we calculate the moles:
Because the reaction shows a 1:1 stoichiometry between
and
, the moles of
ions in the sample are also approximately 0.0376 mol.
Understanding the stoichiometry of reactions is crucial, as it helps chemists quantify reactants and products. For instance, in this case, each mole of
generates one mole of precipitate
. This fundamental principle underlies many laboratory analyses in chemistry and ensures accurate interpretations of experimental results.
Using precise measurements and calculations is key in lab work. A common mistake is improperly converting grams to moles due to incorrect molar masses or unit confusion. Always double-check calculations, especially when measuring sample weights or balancing equations. This ensures the integrity of your results, which is especially important when determining concentrations or moles in a solution.