SAT化学真题练习

　　SAT考试中，SAT化学是大家喜爱的一个理科课程，它的学习以理论和实操为主，主要是一些化学实验的反应原理，还有一些化学元素的记忆，那么今天小编就为大家带来了SAT化学真题，一起来练习一下吧！

　　Have you ever noticed that hot dogs are sold in packages of 10, while the buns come in packages of eight? In this scenario, the buns are the limiting reactant in the sense that they limit the hot dog preparation to eight. The limiting reactant or reagent is the one that is consumed first in the chemical reaction, and its consumption halts the progress of the forward reaction.When answering questions about limiting reagents on the exam, your first step should always be to convert all the masses you were given into moles. You should set up your table as you did before, only now you’ll have two amounts and thus two numbers of moles to get you started. Let’s look at a specific question, involving the Haber process. Basically, this is the process of making ammonia from the reaction of nitrogen and hydrogen gases. The reaction is shown below:Molar mass(28.02)(2.02)(17.04)

　　Balanced equation N2 +3H2 2NH3

　　No. of moles

　　Amount

　　Suppose you have a total of 25.0 kg of nitrogen to react with a total of 5.00 kg of hydrogen. What mass of ammonia can be produced? Which reactant is the limiting reactant? What is the mass of the reactant that’s in excess? Insert the masses in the correct rows and find the number of moles of both.

　　Molar mass(28.02)(2.02)(17.04)

　　Balanced equation N2 +3H2 2NH3

　　No. of moles892 mol2475 mol

　　Amount25,000 g5000 g

　　Start with nitrogen. You have 892 moles of it available, and in order for the nitrogen to react completely with hydrogen, you’d need 3(892 mol) = 2676 moles of hydrogen, which you don’t have. Therefore, hydrogen is the limiting reagent. Now let’s answer the other parts of the question. The mass of ammonia that can be produced is limited by the amount of hydrogen, so do your calculations based on the number of moles of hydrogen available. Your chart should look like the one below:Molar mass(14.02)(2.02)(17.04)

　　Balanced equationN2 +3H2 2NH3

　　No. of moles825 mol used2475 mol usedtherefore 1650 mol produced

　　Amount 892 mol　23,117 g used 25,000g 5000 g1650 mol (17.04) = 28,116 g produced

　　以上就是小编为大家分享的SAT化学真题训练，希望大家在备考中一定要重视起来，提高自己的考试分数，如果还想了解更多关于SAT2化学考试、SAT2考试报名的内容，可以添加我们的客服微信kewo11。