# Stoichiometry Essay

Submitted By christopherseven
Words: 2712
Pages: 11

Can the Charge of Iron be Calculated in a Single Replacement Reaction With Copper (II) Sulfate, and Can a Hydrate be Predicted From an Initial and Final Mass? Sometimes atoms have more or less electrons than they do protons. These atoms are known as ions, any atom or molecule that has an ionic charge. Some atoms or molecules have “common” ionic charges, or a number of electrons that is normal for them. An example of this is sulfate, or which has an ionic charge of 2-, which means it has 2 more electrons than protons. Now atoms that have negative ionic charges are known as “anions”. Atoms that have positive ionic charges are known as “cations”. Cations and anions will bond to usually form ionic charges of 0. In two of our experiments, we used copper (II) sulfate, or CuS. Since copper has a charge of 2+, and sulfate has a charge of 2-, the new charge of copper (II) sulfate is 0. Copper is the cation, and sulfate is the anion. In some reactions, possibly involving sulfate, one cation is replaced by another. This is only possible when the latter cation is more reactive than the original. This occurred in our first experiment, where iron replaced copper because iron is more reactive. Another compound associated with bonds and reactions is a hydrate. A hydrate is a compound or element that has bonded with water. There is a ratio between the water molecules and the elemental molecules. These definitions are very interesting, but not very useful unless stoichiometry is studied. Stoichiometry is the relationship between substances in an equation or reaction. Stoichiometry primarily uses moles to calculate masses, volumes, and amounts of substances. By finding the relationship between two substances, the amount of each specific substance can then be calculated. These terms and definitions are key in the experiments conducted in this report, and crucial in both parts. PART 1 INTRO: After the aforementioned definitions and terms were defined, a problem arose. If iron was added to copper (II) sulfate in a single replacement reaction, and the final copper was found, could the charge of the iron be found? So essentially, if in a single replacement reaction, the final standalone cation’s mass was known and the initial standalone cation’s mass was known, could one calculate the charge of the initial cation? In equation form this appears as such: . The charge of the iron ion was unknown. Iron only has two common charges, 2+ and 3+. If in this reaction iron (II) was used then the full chemical equation and reaction would occur as:. Now we knew the initial iron we would be using in this reaction, 2.00 g of iron filings. However, we didn’t know the charge. So if 2g of iron were used and the iron in question was iron (II), then we could expect a certain amount of copper using these equations: 2g Fe/55.845 (g/mol) Fe = .03581 moles. 55.845 (g/mol) is the molar mass of iron. So we would have .03581 moles of iron. Then, .03581 moles Fe * 1 mol Cu/1 mol Fe = .03581 moles Cu. We multiplied the moles of iron by 1 over 1 because there is 1 mole of iron for every mole of copper. Then, .03581 moles Cu * 63.556 (g/mol) Cu = 2.2756 g Cu. 63.556 (g/mol) is the molar mass of copper. If the iron was iron (II), then 2.2756 grams of copper would be produced from the reaction. Now if the iron was iron (III), then a new equation can be formed: . To calculate the amount of copper in this experiment, these equations were used: 2g Fe/111.69 (g/mol) Fe = .01791. 55.845 (g/mol) is the molar mass of iron, and there are two moles of iron. So we would have .01791 moles of iron. Then, .01791 moles Cu * 190.638 (g/mol) Cu = 3.4143 g Cu. 63.556 (g/mol) is the molar mass of copper, and there are 3 moles of copper. So if the iron was iron (III), then 3.4143 grams of copper would be produced as a result. Our hypothesis was that the iron would be iron (II) and produce 2.2756 grams of copper as a result. In this experiment, iron was the independent