14-7

**Limiting Reagents & Percent Composition Worksheet** **//<---Previous Assignment - Next Unit--->media type="custom" key="12515796"//** ** __Time Length__ ** **__Percent Composition Worksheet__ ** >>> Total mass = 18.015 g. >>>> 2 Hydrogens mass = 2.016 g. %H = (2.016/18.015)(100)=11.19% >>>> 1 Oxygen mass = 15.999 g. %O = (15.999/18.015)(100)=88.81% >>>> I know its right because they add up to 100% 1) CuBr 2 2) NaOH 3) (NH 4 ) 2 S 4) N 2 S 2 5) NH 4 BrO 4
 * 2 Days
 * Calculate the percent composition of the following elements
 * This is like Percent Yield, but you divide the part of the weight of each element by the total weight of the molecule. Then times it by 100.
 * Example - H 2 <span style="font-family: 'Times New Roman',Times,serif; font-size: 140%;">O.
 * <span style="font-family: 'Times New Roman',Times,serif; font-size: 140%;">Write the percent sign.

<span style="font-family: 'Times New Roman',Times,serif;"> ** __Limiting Reagent Worksheet__ ** <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 140%; text-align: left;"> divide the question amount by the equation amount. Convert to grams before you divide. Whichever is the smallest number is the limiting reagent. <span style="font-family: 'Times New Roman',Times,serif; font-size: 140%;"><span style="font-family: 'Times New Roman',Times,serif; font-size: 140%;"> Use the equation ** P 4 O 10 + 6 H 2 O ** → ** H 3 PO 4 ** below

<span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 140%; text-align: left;"> 6) If you had 100 g of both reactants, which would be the limiting reagent? <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 140%; text-align: left;">7) If you react 50 g of the first reactant with 100g of the second, which would be the limiting reagent? <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 140%; text-align: left;">8) if you combine 1000 g of the first reactant with 100 g of the second reactant, which is the limiting reactant? <span style="font-family: 'Times New Roman',Times,serif;">** __Test Review Questions__ ** <span style="font-family: 'Times New Roman',Times,serif; font-size: 140%; line-height: 27px;">9) What is the molar mass of H 2 SO 4 <span style="font-family: 'Times New Roman',Times,serif; font-size: 140%;">? (how many grams does it weigh?) <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 140%; text-align: left;"> 10) How much does 3.5 moles of H 2 SO 4 weigh? (Remember that 1 mol = the molar mass (add it up from the Periodic Table). <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 140%; text-align: left;"> 11) How many molecules are in 2.4 moles of H 2 SO 4 ? (remember 1 mol = 6.022 x 10 23 molecules) <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 140%; text-align: left;"> 12) How many Liters does 3.2 moles of H 2 SO 4 as a gas occupy ? (remember 1 mol = 22.4 L)  <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 140%; text-align: left; vertical-align: sub;">Use the equation **  8 Fe + S 8  ** → ** 8 FeS **below <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 140%; line-height: 27px; text-align: left;">13) How many grams of FeS are produced by 15 g of Fe? <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 140%; line-height: 27px; text-align: left;">14) If FeS was a gas how many Liters would be produced by 15 g of Fe? <span style="display: block; font-family: 'Times New Roman',Times,serif; font-size: 140%; line-height: 27px; text-align: left;">15) If you had 100 grams of Fe and 200 g of S 8, which would be the limiting reagent? (remember to divide the question amount by the equation amount. Convert to grams before you divide. Whichever is the smallest number is the limiting reagent.) <span style="font-family: 'Times New Roman',Times,serif; font-size: 140%;">16) what is a limiting reagent? <span style="font-family: 'Times New Roman',Times,serif; font-size: 140%;">17) What did you use to calculate the empirical formula? (look at the title of the chart from the project on 14-5)