General Knowledge
In which part of a chemical reaction do reagents appear?
The product.
What is a limiting reagent?
The reagent that is completely used up or reacted.
What is the theoretical yield?
The maximum amount of product that could be formed from given amounts of reactants.
CH4 + 2O2 → CO2 + 2H2O
24 grams of CH4 was added to the above reaction. Calculate the theoretical yield of CO2.
66 grams
What is the formula for finding percent yield?
What is (actual yield / theoretical yield)x 100 = percent yield.
What happens when there isn't enough of one reactant in a chemical reaction?
The reaction stops abruptly.
What is an excess reagent?
Reactants that are not used up when the reaction is finished
What is the actual yield?
The amount of product that actually forms when the reaction is carried out in the laboratory
Given the reaction
Na2S(aq) + 2AgNO3(aq) → Ag2S(s) + 2NaNO3(aq)
How many grams of Ag2S will form when 3.94 g of AgNO3 and an excess of Na2S are reacted together?
2.87 g of Ag2S will be produced from 3.94 g of AgNO3
What is the percent yield if you have an actual yield of 143g of H and a theoretical yield of 167g. Calculate to Three significant figures.
What is 85.6%.
A molar mass always has the ratio of what units?
What is grams per mole.
Which product in a reaction is the limiting reagent?
The one that produces less product is the limiting reagent
You need to make sure that an equation is ______ before finding the theoretical and actual yield.
balanced
If 4.50 g of HCl are reacted with 15.00 g of CaCO3, according to the following balanced chemical equation, calculate the theoretical yield of CO2.
2HCl + CaCO3 → CaCl2 + H2O + CO
2.71g CO2
If the theoretical yield is 75g N and the percent yield is 45%, what is the actual yield. Calculate answer to three significant figures.
What is 33.8g N.
A mole ratio always has the ratio of what units?
What is moles/moles.
Find the limiting reagent by looking at the number of _______ of each reactant.
moles
To find the theoretical yield, you need to find the _____ _____ between the _____ and the _____.
mole, ratio, reactant, product
For the balanced equation shown below, if 93.8 grams of PCl5 were reacted with 20.3 grams of H2O, how many grams of H3PO4 would be produced?
PCl5+4H2O=>H3PO4+5HCl
27.63 grams of H3PO4
Produced from 16 g H2(2.01588) ,the actual yield of H2O(18.0153) is 138g . What is the percent yield? Three Significant Figures.
2H2+O2=2H2O
What is 96.7%.
Why are excess and limiting reagents important?
They let us know when the reaction cannot proceed and limits it from continuing.
What is the first step that needs to be completed in order to find the limiting reagent in a chemical reaction?
Balance the equation.
What does percent yield indicate?
The efficiency of the lab
For the balanced equation shown below, if 18.3 grams of C2H5Cl were reacted with 37.3 grams of O2, how many grams of Cl2 would be produced?
4C2H5Cl+13O2=>8CO2+10H2O+2Cl2
10.1 grams of Cl2
What is the percent yield of the following reaction if 60 grams of CaCO3(100.087) produces 15 grams (actual yield) of CaO(56.0774)? CaCO3→CaO + CO2
What is 44.6% .