The Cu2+ ions in this experiment are produced by the reaction of 1.0g of copper.
Information already found out
.016 mol Cu2+ produced
Overall reaction is
Cu2+(aq)+Cl-(aq)+Cu(s)=2 CuCl(s)
Maximum mass of CuCl that can be prepared from the reaction sequence of this experiment using 1.00g of Cu turnings to prepare the Cu2+ solution is 3.1679 g CuCl
A sample of the compound prepared in this experiment, weighing .1021g, is dissolved in HNO3 and diluted to a volume of 100mL. A 10mL aliquot of that solution is mixed with 10mL 6 M NH3. The [Cu(NH3)4 2+] in the resulting solution is 5.16x10^-3 M.
How many moles of Cu were in the original sample, which had been effectively diluted to a volume of 200mL?
How many grams of Cu were in the sample?
How many grams of Cl were in the sample?How many moles?
What is the formula of the Copper Chloride compound?
What exactly do you not understand about this?
To answer these questions, we need to use stoichiometry and concentration calculations. Let's go step by step:
1. Determine the number of moles of Cu in the original sample (which has been effectively diluted to a volume of 200 mL):
Given:
Volume of the original sample = 100 mL
Volume after dilution = 200 mL
Concentration of [Cu(NH3)4 2+] = 5.16 × 10^-3 M
First, calculate the number of moles of [Cu(NH3)4 2+] in the 10 mL aliquot:
moles of [Cu(NH3)4 2+] = Concentration × Volume
moles of [Cu(NH3)4 2+] = 5.16 × 10^-3 M × 10 mL × (1 L / 1000 mL)
moles of [Cu(NH3)4 2+] = 5.16 × 10^-5 mol
Since the dilution was 1:2 (100 mL to 200 mL), the number of moles of Cu in the original sample will be twice that of the aliquot:
moles of Cu = 5.16 × 10^-5 mol × 2
moles of Cu = 1.032 × 10^-4 mol
2. Calculate the grams of Cu in the sample using its molar mass:
Given:
Molar mass of Cu = 63.55 g/mol (from the periodic table)
grams of Cu = moles of Cu × molar mass of Cu
grams of Cu = 1.032 × 10^-4 mol × 63.55 g/mol
grams of Cu = 0.00656 g (rounded to four decimal places)
3. Calculate the grams of Cl in the sample using the stoichiometry of the reaction:
Given:
Mass of the CuCl compound = 3.1679 g
From the balanced equation: Cu2+(aq) + Cl-(aq) + Cu(s) → 2 CuCl(s)
The stoichiometric ratio between Cu and Cl is 1:2.
moles of CuCl = 0.016 mol (as given in the information)
moles of Cl = 2 × moles of CuCl
moles of Cl = 2 × 0.016 mol
moles of Cl = 0.032 mol
grams of Cl = moles of Cl × molar mass of Cl
grams of Cl = 0.032 mol × 35.45 g/mol (molar mass of Cl)
grams of Cl = 1.132 g (rounded to three decimal places)
4. The formula of the Copper Chloride compound:
From the balanced equation: Cu2+(aq) + Cl-(aq) + Cu(s) → 2 CuCl(s)
We can see that the formula of the Copper Chloride compound is CuCl.
To summarize the answers to your questions:
- The number of moles of Cu in the original sample, effectively diluted to a volume of 200 mL, is 1.032 × 10^-4 mol.
- The grams of Cu in the sample are 0.00656 g.
- The grams of Cl in the sample are 1.132 g.
- The formula of the Copper Chloride compound is CuCl.