Combien ? La quantité de changement chimique
Baccalauréat international · IB Diploma · Chemistry · HL Sujet 16 4:30 Narration en anglais · Sous-titres anglais + 中文 incrustés
Chapitres
Transcript
A burette reading is not the delivered volume.
滴定管读数并非实际释放的体积。
The titre 滴定体积 is the difference between final and initial readings, and both readings have uncertainty.
滴定体积是最终读数与初始读数的差值，且两个读数均存在不确定度。
A titration measures the amount of one solution needed to react with a known amount of another.
滴定用于测量与已知量的另一种溶液反应所需的一种溶液的体积。
The equation gives the mole ratio.
该方程式给出摩尔比。
An indicator endpoint approximates the equivalence point, or stoichiometric point, when a suitable indicator is used.
当使用合适的指示剂时，指示剂终点近似于化学计量点。
Titre: The volume delivered between two burette readings.
滴定体积：两次滴定管读数之间释放的体积。
Equivalence point: The point of stoichiometric reaction completion.
化学计量点：化学反应按化学计量关系完全完成的点。
Calculate the known amount first, apply the stoichiometric ratio, then divide by the unknown solution volume in cubic decimetres.
首先计算已知量，应用化学计量比，然后除以未知溶液的体积（单位为立方分米）。
Use concordant titres as required by the school method and report the accepted values.
按照学校方法要求使用一致滴定值，并报告公认数值。
In the lab: Rinse the burette with its solution and the pipette with the solution it transfers.
在实验室中，用待装溶液润洗滴定管，用待移取溶液润洗移液管。
Rinse the flask with distilled water.
用蒸馏水润洗锥形瓶。
Add titrant slowly near the endpoint, swirl, and read the meniscus at eye level.
接近终点时缓慢加入滴定剂，摇动锥形瓶，并在视线水平处读取弯月面读数。
Use a white tile and appropriate eye protection.
使用白色衬板并佩戴适当的护目镜。
Known: twenty-five point zero cubic centimetres of acid reacts one to one with twenty point zero cubic centimetres of zero point one zero zero moles per cubic decimetre alkali.
已知：25.0 cm³ 酸与 20.0 cm³ 浓度为 0.100 mol·dm⁻³ 的碱按 1:1 反应。
N equals C V equals zero point one zero zero times zero point zero two zero zero equals zero point zero zero two zero zero moles.
n = cV = 0.100 × 0.0200 = 0.00200 mol。
Acid amount is zero point zero zero two zero zero moles.
酸的物质的量为 0.00200 mol。
C equals n over V equals zero point zero zero two zero zero divided by zero point zero two five zero equals zero point zero eight zero zero moles per cubic decimetre.
c = n/V = 0.00200 / 0.0250 = 0.0800 mol·dm⁻³。
Your turn: Burette readings are 1.40 and 23.65 cubic centimetres.
轮到你了。 滴定管读数分别为 1.40 和 23.65 立方厘米。
Calculate titre.
请计算滴定体积。
Adding distilled water to the flask changes volume, but not the transferred amount of analyte.
向锥形瓶中加入蒸馏水会改变体积，但不会改变已转移的待测物量。
Do not average a rough titre with carefully measured concordant values.
切勿将粗略滴定值与精确测量的相符值取平均。
Not true: A flask must be rinsed with analyte to avoid dilution of its mole amount.
不正确。 锥形瓶不能用待测液润洗以避免稀释其物质的量。
The pipette delivers a fixed AMOUNT of analyte into the flask; extra water in the flask changes the volume but not the moles present, and the titration measures moles.
移液管向锥形瓶中移入固定量的待测液。 锥形瓶中的额外水会改变体积，但不会改变其中存在的物质的量，而滴定测量的是物质的量。
Rinsing the flask with analyte would add unknown extra moles and spoil the result.
用待测液润洗锥形瓶会引入未知的额外物质的量，从而破坏实验结果。
A titration measures the amount of one solution needed to react with a known amount of another.
滴定测量与已知量的另一种物质反应所需的某种溶液的量。
Calculate the known amount first, apply the stoichiometric ratio, then divide by the unknown solution volume in cubic decimetres.
首先计算已知量，应用化学计量比，然后除以未知溶液的体积（单位为立方分米）。
Watch for adding distilled water to the flask changes volume but not the transferred amount of analyte.
注意：向烧瓶中加入蒸馏水会改变体积，但不会改变转移的分析物的量。
Burette readings are zero point eight five and twenty-one point three five cubic centimetres.
滴定管读数分别为0.85和21.35立方厘米。
Find the titre.
求滴定体积。
Extra water in the flask does not change the amount delivered by the pipette.
锥形瓶中的额外水不会改变移液管所转移的量。
The result is a titre of 20.50 cubic centimetres.
结果是滴定体积为20.50立方厘米。
Read the burette at eye level before and after.
滴定前后都要平视读取滴定管读数。
The difference is the titre, the volume delivered.
两者之差就是滴定体积，即加入的体积。
Convert it to moles and use the balanced equation’s ratio.
把它换算成物质的量，再用配平方程式的比例计算。
In a fictional one-to-one titration, 25.0 cubic centimetres of acid need 18.0 cubic centimetres of 0.100 moles per cubic decimetre alkali.
虚构的1:1滴定。 25.0 cm³酸需要18.0 cm³浓度为0.100 mol/dm³的碱液。
Find the acid concentration and explain how an overshot endpoint biases it.
求酸的浓度，并解释终点过量如何导致结果偏差。
n is 0.100 times 0.0180, which is 0.00180 moles; c is 0.00180 divided by 0.0250, which is 0.0720 moles per cubic decimetre.
n 等于 0.100 乘以 0.0180，即 0.00180 mol；c 等于 0.00180 除以 0.0250，即 0.0720 mol/dm³。
Overshoot increases the recorded volume and the inferred concentration in this model.
在这个模型中，滴定过量会使记录的体积和推算出的浓度都偏大。
Use concordant runs.
应使用平行一致的数据。
Retrieve the technical meanings, then vary one input in the original transfer and justify the model condition.
回顾专业术语的含义，然后在原始迁移中改变一个输入变量，并为模型条件提供依据。