(07.05 HC)In an experiment, sulfuric acid reacted with different volumes of sodium thiosulfate in water. A yellow precipitate wa
s formed during thereaction. A cross drawn at the base of each flask became gradually invisible due the formation of this yellow precipitate. The time taken for thecross to become invisible was recorded. A partial record of the experiment is shown.Experimental RecordFlask Volume of Volume of Volume of TimeH2SO4 Sodium Thiosulfate Water5 mL 50 mL10 mL 119 seconds5 mL 40 ml10 mL3 5 ml 30 ml120 mL4 15 ml 120 mL30 mLBased on your knowledge of factors that affect the rates of chemical reactions, predict the trend in the last column of the experimental record.Use complete sentences to explain the trend you predicted. You do not have to determine exact values for time; just describe the trend youwould expect (increase or decrease) and why it occurs.
2 answers:
The rate of the reaction usually depends on the concentration of the reactants. We have to reactants in this reaction, sulfuric acid and sodium thiosulfate. Let's look at the values that were recorded.
The volume of sulfuric acid that is added is constant, but the volume of sodium thiosulfate is not. It decreases and the volume of water increases, so we are diluting the sodium thiosulfate. The concentration of one reactant is decreasing. So the rate of the reaction is also decreasing. Then the time that it takes for the cross to become invisible should increase.
Answer: the time should increase.
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Answer :
a. The oxidizing agent is:
b. The reducing agent is:
Explanation :
Redox reaction or Oxidation-reduction reaction : It is defined as the reaction in which the oxidation and reduction reaction takes place simultaneously.
Oxidation reaction : It is defined as the reaction in which a substance looses its electrons. In this, oxidation state of an element increases. Or we can say that in oxidation, the loss of electrons takes place.
Reduction reaction : It is defined as the reaction in which a substance gains electrons. In this, oxidation state of an element decreases. Or we can say that in reduction, the gain of electrons takes place.
Reducing agent : It is defined as the agent which helps the other substance to reduce and itself gets oxidized. Thus, it will undergo oxidation reaction.
Oxidizing agent : It is defined as the agent which helps the other substance to oxidize and itself gets reduced. Thus, it will undergo reduction reaction.
The given chemical reaction is,
The oxidation-reduction half reaction will be :
Oxidation :
Reduction :
Now balance oxygen atom on both side.
Oxidation :
Reduction :
Now balance hydrogen atom on both side.
Oxidation :
Reduction :
Now balance the charge.
Oxidation :
Reduction :
In order to balance the electrons, we multiply the oxidation reaction by 6 and reduction reaction by 4 and then added both equation, we get the balanced redox reaction.
Oxidation :
Reduction :
The balanced chemical equation in acidic medium will be,
In the redox reaction, act as oxidizing agent and
act as an reducing agent.