Nail Lab 铁钉实验

PART.1

Purpose 目的

To explain the chemical reaction between copper (II) chloride and iron.

解释氯化铜和铁的化学反应

PART.2

Materials 材料

Nail

Jar

Steel wool

Electronic scale

Laboratory sealing film

钉子

广口瓶

钢丝棉

电子秤

实验室密封膜

Diagram

Chemicals 化学品

Procedures 实验步骤

Observation and Data collection

观察结果和数据收集

    Obersvation：After putting the nail into copper(II) chloride, Fe and CuCl2 chemically react to double replacement, and finally the copper forms a brown cluster around the nail.Finally, the water in copper evaporates.The solvent color change from blue to yellow.

    观察结果：将钉子放入氯化铜(II)中后，Fe和CuCl2发生双置换反应，最终铜在钉子周围形成棕色簇，铜中的水蒸发，溶剂颜色由蓝色变为黄色。

The first day  第一天

The second day  第二天

The third day  第三天

Data Collection: 数据收集

Data Analysis: 数据分析

Measure the amount of copper and copper(II) chloride to get their chemical equation:

final - initial = chemical that participates in the chemical reaction

weight s of Fe: 9.95-9.78=-0.17g ( been used)

weight of copper: 76.77-76.99=0.22g (been form)

测量铜和氯化铜(II)的含量，得到它们的化学方程式：

初始量-最终量 = 参与反应的化合物

Fe重量: 9.95-9.78=-0.17g (使用的)

Cu重量: 76.77-76.99=0.22g (形成的)

Mass / volume = molarity * molar mass

质量/体积 = 摩尔浓度*摩尔质量

100ml=0.1L

0.1L=0.5molar mass

Molar mass:0.1/0.5=0.2 mole

摩尔质量:0.1/0.5=0.2 mole

Fe + CuCl2 → FeCl2 + Cu

1)Determine limiting reactant and excess reactant

  求出限制反应物和过量反应物

Fe:0.17g Fe x 1 mole Fe/55.845g Fe ➗ 1 = 0.003= 3 x 10^-3     LR

CuCl2:0.2 mole CuCl2 ➗1 =0.2    ER

0.0030 mol Fe x 1 mole Cu/ 1 mole Fe x 63.546g Cu/ 1 mol Cu= 0.2g Cu

2Fe + 3CuCl2 → 2FeCl3 + 3Cu

Fe:0.17g Fe x 1 mole Fe/55.845g Fe ➗ 2 = 0.002     LR

CuCl2:0.2 mole CuCl2 ➗ 3 =0.067    ER

0.0030 mol Fe x 3 mole Cu/ 2 mol Fe x 63.546g Cu/ 1 mol Cu= 0.3g Cu

2)Calculate the % yield of Cu

   计算Cu的产出率

Fe(s)+ CuCl2(aq→ FeCl2(aq)+ Cu(s)

%yield = (actual yield/theoretical yield) x 100

产出率 = (实际产量/理论产量) x 100

110% = (0.22/0.2)x100

2Fe(s)+ 3CuCl2(aq)→ 2FeCl3(aq)+ 3Cu(s)

%yield = (actual yield/theoretical yield) x 100

产出率 = (实际产量/理论产量) x 100

73.3% = (0.22/0.3)x100

Result: The data of the first equation is close to the product that we got, therefore the second equation is the actual chemical equation.

结果:第一个方程的数据与我们得到的产物很接近，因此第二个方程是实际的化学方程。

3)Calculate the # of Cu atoms in your product sample

计算产物样本中Cu原子的#

1 mole = 6.02 x 10^23 atoms

1 mole = 6.02 x1023atoms

0.22g Cu x 1 mole/ 63.546g Cu x 6.02 x 1023Cu atoms = 2 x 102atoms Cu

4)Write the balanced redox ½ rxns

写出平衡的氧化还原反应式

Fe(s)+ CuCl2(aq→ FeCl2(aq)+ Cu(s)

Reduction 还原

Cu2++ 2e− → Cu

Oxidation 氧化

Fe→ Fe2++ 2e−

Complete Equation完整化学方程式: Cu2+(aq) +2Cl1-(aq)  + Fe(s)→ Cu (s)+ Fe2+(aq)+ 2Cl1-(aq)-

Ionic Equation离子方程式: Cu2+(aq) + Fe(s)→ Cu (s)+ Fe2+(aq)

  Particle diagram 粒子图

Discussion讨论

  The purpose of this lab is using the single replacement that happens between Fe and Copper II chloride to figure out the actual chemical equation of the reaction that occurs in this lab. Because the Copper inside the solvent that is unknown for it is +2 charge or +3 charge. So people can say that a less reactive element can be replaced by a more reactive element in a compound to determine the chemical equation.

    这个实验的目的是利用发生在Fe和氯化铜之间的单一置换来计算出反应的实际化学方程式。因为溶剂中的铜不知道是+2电荷还是+3电荷，人们可以根据化合物中活性较低的元素可以被活性较强的元素所取代来确定化学方程式。

   For doing the calculation of the stoichiometry to figure out the chemical equation, record the data of Fe has been used and amount of the Copper II has been formed are the requirements. There are a few precautions still to be reminded in this lab. The first nail is easy to rust. Before we conduct the experiment, we must ensure that there is only Fe on the nail, otherwise the contact area between Fe and Copper II chloride will affect the efficiency of the chemical reaction between them. The second point is also the one that is most easily overlooked. After we take out the nail that has chemically reacted with copperII chloride, no matter how carefully and smoothly we take it out, it will shake in the process, which leads to the fusion of the copper molecule and the solvent. The possibility exists, so after we take out the nail, it is best to let it sit for a period of time to allow the copper to completely settle before measuring is the best way to ensure the accuracy of the experiment.

    为了用化学计量学计算出化学方程式，需要记录铁的用量和铜的形成量。在这个实验中有一些事项需要注意，第一，第一颗钉子容易生锈，在我们进行实验之前，一定要保证钉子上只有Fe，否则Fe和氯化铜的接触面积会影响它们之间的化学反应效率。第二，我们取出与氯化铜发生化学反应的钉子后，无论多么小心、多么平稳，它都会在这个过程中晃动，导致铜分子与溶剂发生融合。所以我们取出钉子后，最好让它静置一段时间，让铜完全沉淀下来，再进行测量，从而保证实验准确性。

   Stoichiometry is the main theory used to find the correct chemical equation. It expresses the relationship between the relative amounts of substances participating in a reaction or forming a compound.After we have written two chemical formulas that may occur （Fe(s) + CuCl2(aq → FeCl2(aq) + Cu(s) and 2Fe + 3CuCl2 → 2FeCl3 + 3Cu), we need to apply stoichiometry to determine which chemical equation actually occurs. We use the collected data to find out that Fe is a limiting reactant, and then use it to figure out how much Cu formed after reaction, and then use two chemical equations to get the theoretical amount of Cu that will be form and compare to the actual Cu formed in our lab, we can know that the Cu quantity calculated by Fe(s) + CuCl2(aq → FeCl2(aq) + Cu(s)is the most similar to the experimental result, we can know that this is the correct chemical equation.

    化学计量学是用来找到正确化学方程式的主要理论。它表示参与反应或形成化合物的物质的相对数量之间的关系。在我们写了两个可能发生的化学公式(Fe(s) + CuCl2(aq→FeCl2(aq) + Cu(s)和2Fe + 3CuCl2→2FeCl3 + 3Cu)之后，我们需要应用化学计量学来确定到底发生了哪个化学反应。我们使用收集到的数据发现铁是一个限制反应物，使用它来计算出反应后形成的铜，然后使用两个化学方程得到理论的铜的量，它将与实际产生的铜的量比较。在实验中，我们可以知道由Fe(s) + CuCl2 (aq→FeCl2 (aq) +Cu(s)计算的铜量与实验结果最接近，因此这是正确的化学方程式。

    Redox reaction is a chemical reaction in which the oxidation number of elements has corresponding rise and fall changes before and after the reaction. This reaction can be understood as consisting of two half-reactions, namely oxidation reaction and reduction reaction. Such reactions obey the conservation of charge.Redox reactions have four categories that belong to it, they are single replacement, synthesis, decomposition and combustion. The exact name of what kind of is single replacement redox reaction.

    一种元素的氧化量在反应前后有相应的升降变化的化学反应被称作氧化还原反应是。这个反应可以理解为两个半反应，即氧化反应和还原反应。这种反应遵从电荷守恒定律。氧化还原反应有四类，分别是单一置换反应、合成反应、分解反应和燃烧反应。确切的名称是单一置换氧化还原反应。

Error Analysis 误差分析

approximated value近似值 : 0.22g Cu

exact value精确值: 0.2g Cu

0.22-0.2/0.2 x 100 =9.1%

Error 1: Did not wait for the solvent to completely dry out when measuring Copper II precipitation.

Propagation: Because of there still have some solvent mix inside the copper II precipitation, which leads to copper II measuring weight higher than the actual weight, because there is only one day to let it air dry, if it is naturally air-dried, the time is not enough, so in order to avoid this error, we It’s best to turn on the fan, let it be in an environment with flowing wind.

错误1:测量铜的沉淀时没有等待溶剂完全干燥。

简述:由于铜内部还有一些溶剂的混合沉淀，铜的测量重量高于实际重量。因为只有一天的时间让它风干，如果是自然风干，时间是不够的，所以为了避免这种误差，我们最好打开风扇，让它处于有流动风的环境中。

Error 2:When taking out the nail and separating the copper attach on it, use the nail to stir in the solvent.

Propagation: Stirring in the solvent with nails caused a small part of the copper molecules to break away from the precipitation group and mix with the solvent, so some copper molecules were poured out together with the solvent, which resulted in a reduction in the actual weight of the copper. In order to avoid this error, we When taking out the nail, it is best to rinse the copper on it with water instead of stirring it, and then filter it with a filter when pouring out the solvent.

错误2:取出铁钉并将铜片分开时，用铁钉在溶剂中搅拌。

简述:用钉子在溶剂中搅拌，使一小部分铜分子脱离沉淀组与溶剂混合，因此有一部分铜分子随溶剂一同倒出，导致铜的实际重量降低。为了避免这种错误，我们在取出钉子时，最好是用水冲洗上面的铜而不是搅拌，然后在倒出溶剂时用过滤器过滤。

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