Limiting Reactant Problems in Chemistry

A balanced chemical equation shows the molar amounts of reactants that will react together to produce molar amounts of products. In the real world, reactants are rarely brought together with the exact amount needed. One reactant will be completely used up before the others. The reactant used up first is known as the ​limiting reactant. The other reactants are partially consumed where the remaining amount is considered in excess. This example problem demonstrates a method to determine the limiting reactant of a chemical reaction. Example Problem Sodium hydroxide (NaOH) reacts with phosphoric acid (H3PO4) to form sodium phosphate (Na3PO4) and water (H2O) by the reaction: 3 NaOH(aq) H3PO4(aq) → Na3PO4(aq) 3 H2O(l) If 35.60 grams of NaOH is reacted with 30.80 grams of H3PO4, a. How many grams of Na3PO4 are formed?b. What is the limiting reactant?c. How many grams of the excess reactant remains when the reaction is complete? Useful information: Molar mass of NaOH 40.00 gramsMolar mass of H3PO4 98.00 gramsMolar mass of Na3PO4 163.94 grams Solution To determine the limiting reactant, calculate the amount of product formed by each reactant. The reactant the produces the least amount of product is the limiting reactant. To determine the number of grams of Na3PO4 formed: grams Na3PO4 (grams reactant) x (mole of reactant/molar mass of reactant) x (mole ratio: product/reactant) x (molar mass of product/mole product) Amount of Na3PO4 formed from 35.60 grams of NaOH grams Na3PO4 (35.60 g NaOH) x (1 mol NaOH/40.00 g NaOH) x (1 mol Na3PO4/3 mol NaOH) x (163.94 g Na3PO4/1 mol Na3PO4)grams of Na3PO4 48.64 grams Amount of Na3PO4 formed from 30.80 grams of H3PO4 grams Na3PO4 (30.80 g H3PO4) x (1 mol H3PO4/98.00 grams H3PO4) x (1 mol Na3PO4/1 mol H3PO4) x (163.94 g Na3PO4/1 mol Na3PO4)grams Na3PO4 51.52 grams The sodium hydroxide formed less product than the phosphoric acid. This means the sodium hydroxide was the limiting reactant and 48.64 grams of sodium phosphate is formed. To determine the amount of excess reactant remaining, the amount used is needed. grams of reactant used (grams of product formed) x (1 mol of product/molar mass of product) x (mole ratio of reactant/product) x (molar mass of reactant)grams of H3PO4 used (48.64 grams Na3PO4) x (1 mol Na3PO4/163.94 g Na3PO4) x (1 mol H3PO4/1 mol Na3PO4) x (98 g H3PO4/1 mol)grams of H3PO4 used 29.08 grams This number can be used to determine the remaining amount of excess reactant. Grams H3PO4 remaining initial grams H3PO4 - grams H3PO4 usedgrams H3PO4 remaining 30.80 grams - 29.08 gramsgrams H3PO4 remaining 1.72 grams Answer When 35.60 grams of NaOH is reacted with 30.80 grams of H3PO4, a. 48.64 grams of Na3PO4 are formed.b. NaOH was the limiting reactant.c. 1.72 grams of H3PO4 remain at completion.

Postag197v1 And Buddy D. Therapist Dan - 942 Words

Bandito and Buddy-D Therapist Dan: â€Å"We’ve talked a lot about Xavier and a little about his friends. What about you and your friends. Don’t you think that’s worth talking about?† Me: â€Å"Sure. Where should I start?† Therapist Dan: â€Å"With whomever you want.† Me: â€Å"Well, I first met Bandito in my high school geometry class. I thought he was strange looking with his huge clunky looking metallic braces, and half a tongue. He looked like a Mexican Adam Sandler, but he had this infectious charm about him. He was outspokenly funny in class and I wanted to share that laughter with him. I wanted to be friends with Bandito, but I didn’t know how until Xavier, my best friend, invited me to hang with him and his new friend Buddy-D one Friday after school. Buddy-D was a larger than life kid physically (he weighed 400 lbs.) and was as sharp mentally as a samurai sword. He sported wire framed nerdy eye glasses, his skin was a light brown and he wore a ponytail. He looked like a big fucking Samoan, okay. When I came over to his house with Xavier, I realized he was in my social studies class, so we were familiar with each other already. Therapist Dan: â€Å"I don’t mean to interrupt, but was Buddy-D your corpulent friend the one you hung out with until 4:00 A.M. at Denny’s?† Me: â€Å"Yes, but that happened a long after I first met him. So he was hospitable, offered us drinks and even set up his PlayStation for us to play games with. Xavier and I got comfortable on the comfy couch while Buddy-D was busyShow MoreRelatedPostag197v1 And Buddy D. Therapist Dan939 Words   |  4 PagesBandito and Buddy-D Therapist Dan: â€Å"We’ve spoken a lot about Xavier and some about his mates. What about you and your mates. Don’t you reason that’s worth speaking about?† Me: â€Å"Sure. Where shall I start?† Therapist Dan: â€Å"With whomever you want.† Me: â€Å"Well, I met Bandito in my high school geometry class. I thought he appeared strange with his massive awkward looking metal braces and half a tongue. He looked like a Mexican Adam Sandler, but he had this contagious charm about him. He was outspokenly

A Good Man Is Hard to Find. Free Essays

Fiction Essay Nobel Prize winner William Faulkner said that a writer must â€Å"leave no room in his workshop for anything but the old verities and truths of the heart, the old universal truths lacking with any story is ephemeral and doomed- love and honor and pity and pride and compassion and sacrifice. † Flannery O’Connor uses these universal truths in her short story, A Good Man Is Hard to Find. An old southern woman trying to come to terms with the new culture of the south dooms her family by unknowingly leading them to come face to face with a notorious criminal called â€Å"The Misfit†. We will write a custom essay sample on A Good Man Is Hard to Find. or any similar topic only for you Order Now O’Connor pushes her characters to the edge using violence so that they may find grace. In the story, there is a human versus human conflict. The grandmother constantly compares her two grandchildren with the way things used to be in her time. The grandmother says, â€Å"In my time, children were more respectful of their native states and their parents and everything else. † (O’Connor 119). The grandchildren are terribly rude and are always speaking everything that is on their minds without a filter. There is also a human versus environment/society conflict. The grandmother comes from a time where slavery still existed, or, the Old South. She was brought up differently than her grandchildren who represent the New South. Viewing the relationship between the grandmother and the grandchildren, it appears that the cultures of the Old South and New South are polar opposites. This brand new generation has different values due to the changes that were happening in history. Within this story there is another human versus human conflict between the family and the Misfit. When the grandmother recognizes The Misfit and shouts it out, she instantly dooms her family. As The Misfit orders the father and son to be killed first the grandmother tries to reason with him in order to spare her life. Desperately she says, â€Å"I know you’re a good man. You don’t look a bit like you have common blood. I know you must come from nice people! † (O’Connor 127). Surprisingly enough, the grandmother does not seem to be interested in saving the family from this impending doom. She is only interested in saving herself and that is her motivation for trying to reason ith The Misfit. Only during the last moments of her life does she begin to shout out for her son. The story ends tragically because the whole family is murdered. The grandmother realized that her generation was the reason why The Misfit existed calling him â€Å"one of my own children† (O’Connor 132). This goes back to the culture of the Old South, which bred the next generation of the New South. The grandmother realizes that the reason why this new culture is so different is because the Old South created it, old southern values were no longer respected. When The Misfit shoots the grandmother she â€Å"half sat and half lay in a puddle of blood with her legs crossed under her like a child’s and her face smiling up at the cloudless sky. † (O’Connor 132). In these moments after her death O’Connor gave her grace. Even though she has been brutally murdered she has been given this peace as she looks up into the sky. In this story, Flannery O’Connor pushed her characters to the edge by using extreme violence. In â€Å"A Reasonable Use of the Unreasonable,† O’Connor explains her reasons for doing this. O’Connor writes, â€Å"I have found that violence is strangely capable of returning my characters to reality and preparing them to accept their moment of grace. † (O’Connor 1048). The grandmother’s violent murder gave her grace and clarity. O’Connor also shows us that there are humans that fear only for themselves and not others and that sometimes tragedy happens even though it is not fair. But another thing O’Connor shows us is that just like how tragedy happens, grace is also given to those who do not deserve it. How to cite A Good Man Is Hard to Find., Papers