Chemical Analysis
Limiting/ Excess Reagents
Titration
The Curvature of Titration
Let's Do Some Labs!
100
The 3 methods used to analyze an unknown compound
What are colorimetry, gravimetric analysis and titration.
100
The reactant that is completely used up in the reaction
What is the limiting reagent?
100
Label the picture provided
A: burette B: clamp C: titrant D:stand E: Stopcock F: Erlenmeyer flask
100
Describe the shape of a curve of a strong acid titrated with a strong base
100
Which is a precipitate reaction?
(A) SO3 + H2O --> H2SO4
(B) 2AgNO3 + Na2S --> Ag2S + 2NaNO3
(C) CH4 + 2O2 --> CO2 + 2H2O
What is RXN B?
(2AgNO3 + Na2S --> Ag2S + 2NaNO3)
200
The blue to green color emitted when this burned
What is the color of copper
200
Cu + AgNO3 --> Ag + CuNO3 If 9.21 g of copper forms Silver and you also use 17.9 g of silver (I) nitrate, which is your limiting reagent?
What is Silver (I) nitrate.
200
The following data is collected from the titration of 15.0 mL samples of phosphoric acid with 0.112mol/L potassium hyroxide. Find the concentration of the acid.
Trial 1 Trial 2 Trial 3 Trial 4
Final buret reading (mL) 19.3 36.9 17.9 35.3
Initial buret reading (mL) 1.22 19.3 0.40 17.9
Volume added (mL)
What is 4.39 x 10-3 mol/L OR 0.00439 mol/L of acid
200
Describe the shape of a curve of a strong base titrated with a strong acid and the equivalence point value.
equivalence point=pH=7
200
Which indicator would be most useful in identifying the equivalence point of a titration for a solution that has an [H3O+] of 0.02 mol/L at the equivalence point?
What is cresol red (pH range for color change is 0.0-1.0)
300
The determination of the chemical amount of a substances OR the detection of whether a substance is present (HINT: Q and Q)
What is the fundamental difference between quantitative and qualitative analysis
300
Al2(SO3)3 + 6 NaOH ----> 3 Na2SO3 + 2 Al(OH)3 Determine the number of grams of excess reagent left over in the reaction.
What is 1.84 grams NaOH.
300
Titration 1: strong monoprotic acid with a strong base
Titration 2: weak monoprotic acid with a strong base
How does the initial pH and equivalence point pH differ between them?
Initial pH of weak acid solution higher, and pH higher at the equivalence point in the titration of a weak acid
300
Describe the shape of a curve of a di-protic acid titrated with a strong base
300
This apparatus is used in the process commonly as titration.
What is a buret?
400
The use of stoichiometric calculations and a burette to determine the concentration of a unknown solution
What is titration analysis
400
A 50.6 g sample of Mg(OH)2 is reacted with 45.0 g of HCl according to the reaction: Mg(OH)2 + 2 HCl --> MgCl2 + 2 H2O What is the theoretical mass of MgCl2?
What is 58.6g of MgCl2
400
Predict whether the equivalence point of each of the following titrations is below, above, or at pH 7:
1. NaHCO3 titrated with NaOH
2. NH3 titrated with HCl
3. KOH titrated with HBr
What is above pH 7, below pH 7, at pH 7
400
Describe the shape of a curve of a di-protic base titrated with a strong acid
400
Name of solution in the burette during a titration.
What is the titrant?
500
Why might a chemist need to need to carry out qualitative analysis of a solution? Give an example
TO determine whether a compound/substance is present in the sample. Eg. Water testing for toxic or harmful substances.
500
In an experiment 25 grams of chloroform(119.378) and 25 grams of chlorine(70.906) were mixed. Which is the excess reactant? CHCl3 + Cl2 = CCl4 + HCl
What is chlorine
500
During the titration of HCl with NaOH, a very rapid change in pH occurs at the equivalence point which is:
a. when the first addition of known solution is made.
b. when roughly equivalent amounts of H3O+ ions and OH- ions become presen
c. at several point
d. at no point.
What is b?
500
Explain why one might see multiple equivalence points
polyprotic acid/base
500
Thymol blue has two color changes:
1. red to yellow at ~pH 3
2. yellow to blue at ~pH 9
Which color change will generally be more suitable for titration of a weak acid with a strong base?
yellow to blue