The Synthesis of Silver

One experiment and one report per person. Pairs are not permitted, and reports with identical data will not be marked.

The Report

Include your experimental data and calculations. Lay out all calculations attractively (with no scratching out) showing all steps, units, and correct significant figures.

The Problem

Today you will make silver metal. Not from lead, like alchemists would have wanted, but from silver nitrate solution reacting with copper. It is a beautiful reaction so keep your eye on it – for the first 20 minutes especially. But the real beauty will be that you will be able to predict the mass of product to the nearest 0.01 g before you actually make it. Now that’s incredible! (You should be able to hear the music swelling in the background. If not, try humming……)
Anyway, this lab is like several that have gone before, so you should be getting the hang of it.

Reagents and Equipment

0.100 M silver nitrate solution – avoid getting splashed with it – it leaves brown spots on your skin. If this happens, don’t worry, because in about 4-6 weeks they flake off.

copper wire – don’t get it in your eye

sand paper – don’t eat it – it’s really hard on your teeth

small test tube

Data

concentration of silver nitrate = ______M

volume of silver nitrate solution (to the nearest 0.01 mL)

final reading on burette ______mL

initial reading on burette ______mL

mass of empty test tube = ______g

mass of test tube and silver = ______g

Procedure

  1. Get a piece of copper wire. Polish it up with sand paper until it is shiny. You don’t have to weigh the wire it because it is the excess reactant.
  1. Find the mass of a medium sized test tube. Make sure the test tube is clean.
  1. Using a burette, place about 20.0 mL of AgNO3(aq) into the test tube. Record the volume of AgNO3(aq) in the data table.
  1. Use a pen or pencil to shape the copper wire into a coil. Leave enough copper at the end to make a hook for the top of the test tube. Place the coil of copper wire into the test tube. Keep a close eye on the system for about 20 minutes.
  1. React for a minimum of 30 minutes. Set aside over night if possible.
  1. Examine your product. The silver will need to be recovered. Shake the silver off the copper wire. You may turf the wire.
  1. Rinse and decant the product at least 5 times. Use de-ionized water. You will inevitably decant away some of the silver at this point, but its not a big problem.
  1. Heat the silver until it is bone dry over a Bunsen burner. Then weigh it.
  1. If you wish, you may keep the silver, flog it on the black market, give it to your mother, encase it in epoxy, or melt it into a broach. You may even give it to your teacher. But make sure you pick it up and feel it – you might be surprised.
  1. Rinse or soak all used glassware in DI water.

Tub & basin will be provided.

Calculations

  1. Write the chemical equation for the reaction. It is a single replacement reaction between silver nitrate solution and copper metal. Copper (II) nitrate was one of the products.
  1. Assume that all the silver nitrate reacted. Calculate the number of moles of silver nitrate that were consumed.
  1. Calculate the theoretical yield of silver metal, first in moles, and then in grams, based on n AgNO3 that were consumed.
  1. Calculate the experimental yield based on the actual mass of silver metal that was present in the test tube at the end of the experiment.
  1. Calculate the percent yield of silver based on the experimental and the theoretical yields. Ideally it should be between 98 and 102%.