A jar contains 100 mL or a 4.0 M silver nitrate solution. What mass of solid copper would you add to bring all the silver out of the solutions as a solid?
To calculate the mass of solid copper needed to react with the silver nitrate solution, we can use the concept of stoichiometry and the balanced chemical equation for the reaction.
The balanced chemical equation for the reaction between silver nitrate (AgNO3) and copper (Cu) is:
2 AgNO3 + Cu -> Cu(NO3)2 + 2 Ag
From the balanced equation, we can see that 2 moles of silver nitrate react with 1 mole of copper to produce 1 mole of copper(II) nitrate and 2 moles of silver.
First, let's calculate the number of moles of silver nitrate in the solution:
Number of moles of AgNO3 = concentration (in moles/liter) * volume (in liters)
= 4.0 M * 0.100 L (since 100 mL = 0.100 L)
= 0.400 moles
Since the stoichiometric ratio between AgNO3 and Cu is 2:1, we need half the number of moles of copper (Cu) to react completely with the silver nitrate.
Number of moles of Cu = 0.400 moles / 2
= 0.200 moles
To calculate the mass of copper (Cu) needed, we need to know the molar mass of copper (Cu). The molar mass of copper is approximately 63.55 g/mol.
Mass of Cu = number of moles * molar mass
= 0.200 moles * 63.55 g/mol
= 12.71 grams
Therefore, you would need to add approximately 12.71 grams of solid copper to completely react with the 4.0 M silver nitrate solution and obtain all the silver as a solid.