Podcast
Questions and Answers
The standard solution employed in most iodometric processes is ______ thiosulfate.
The standard solution employed in most iodometric processes is ______ thiosulfate.
sodium
Potassium ______ is an example of a primary standard strong oxidizing agent.
Potassium ______ is an example of a primary standard strong oxidizing agent.
iodate
The commercial H2O2 can be titrated by ______ method.
The commercial H2O2 can be titrated by ______ method.
iodometric
The volume numbers of H2O2 correspond to the amount of available ______.
The volume numbers of H2O2 correspond to the amount of available ______.
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A 10-volume solution will be about ______ % H2O2 by weight.
A 10-volume solution will be about ______ % H2O2 by weight.
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Weigh approximately ______ g of Na2S2O3.5H2O and dissolve in distilled water.
Weigh approximately ______ g of Na2S2O3.5H2O and dissolve in distilled water.
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Weigh 2 g of ______ into a 100 mL beaker.
Weigh 2 g of ______ into a 100 mL beaker.
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Add a few mL of ______ water and swirl for a few minutes until iodine is dissolved.
Add a few mL of ______ water and swirl for a few minutes until iodine is dissolved.
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Weigh 0.25 g of ______ starch and add it to 50 mL of near boiling water.
Weigh 0.25 g of ______ starch and add it to 50 mL of near boiling water.
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Dissolve a single tablet in 200 mL of ______ water.
Dissolve a single tablet in 200 mL of ______ water.
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Strain the juice through ______ to remove seeds and pulp.
Strain the juice through ______ to remove seeds and pulp.
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Cut a 100 g sample into small pieces and grind in a ______ and pestle.
Cut a 100 g sample into small pieces and grind in a ______ and pestle.
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Alcohol may remove _______________ from skin and cleaners are available for fabric stains.
Alcohol may remove _______________ from skin and cleaners are available for fabric stains.
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Vitamin C, or _______________, is a water-soluble antioxidant that plays a vital role in protecting the body from infection and disease.
Vitamin C, or _______________, is a water-soluble antioxidant that plays a vital role in protecting the body from infection and disease.
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The concentration of the prepared iodine solution can be more accurately determined by titration with a standard solution of _______________ or a standard solution of potassium thiosulfate using a starch indicator.
The concentration of the prepared iodine solution can be more accurately determined by titration with a standard solution of _______________ or a standard solution of potassium thiosulfate using a starch indicator.
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Ascorbic acid is susceptible to _______________ by atmospheric oxygen over time.
Ascorbic acid is susceptible to _______________ by atmospheric oxygen over time.
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If the samples have to be prepared several hours earlier, oxidation can be minimized by the addition of a small amount of _______________ acid.
If the samples have to be prepared several hours earlier, oxidation can be minimized by the addition of a small amount of _______________ acid.
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Identification of the endpoint in this titration is significantly affected by the _______________ of the sample solution used.
Identification of the endpoint in this titration is significantly affected by the _______________ of the sample solution used.
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For strongly colored juices there can be a problem with the ______ and it is advised to carry out a “rough” titration in order to become familiar with any distinct color change which occurs at the ______.
For strongly colored juices there can be a problem with the ______ and it is advised to carry out a “rough” titration in order to become familiar with any distinct color change which occurs at the ______.
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This will also help by establishing an approximate volume of ______ solution required.
This will also help by establishing an approximate volume of ______ solution required.
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The above method may be used to carry out a number of interesting investigations regarding the concentration of ______ C in various foods and drinks:
The above method may be used to carry out a number of interesting investigations regarding the concentration of ______ C in various foods and drinks:
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Centre photo: At the ______ all the ascorbic acid has reacted, and the excess ______ reacts with the starch indicator to give a pale blue color.
Centre photo: At the ______ all the ascorbic acid has reacted, and the excess ______ reacts with the starch indicator to give a pale blue color.
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Figure 2 shows a ______ of commercial fruit juice.
Figure 2 shows a ______ of commercial fruit juice.
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Left photo: before ______, added iodine reacts with ascorbic acid leaving the solution colorless.
Left photo: before ______, added iodine reacts with ascorbic acid leaving the solution colorless.
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The Left flask, before the endpoint, the color of the solution reflects the pale-yellow color of the ______ juice.
The Left flask, before the endpoint, the color of the solution reflects the pale-yellow color of the ______ juice.
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In the Centre flask, at the titration endpoint all the ascorbic acid has reacted, and any excess iodine reacts with the ______ indicator to form a dark blue-black complex.
In the Centre flask, at the titration endpoint all the ascorbic acid has reacted, and any excess iodine reacts with the ______ indicator to form a dark blue-black complex.
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Figure 3 illustrates the titration of ______ juice.
Figure 3 illustrates the titration of ______ juice.
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Figure 4 illustrates the titration of ______ capsicum.
Figure 4 illustrates the titration of ______ capsicum.
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The Centre flask, once all the ascorbic acid has been oxidized, a slight excess of added iodine complexes with the ______ indicator, giving the solution a green colour in this case.
The Centre flask, once all the ascorbic acid has been oxidized, a slight excess of added iodine complexes with the ______ indicator, giving the solution a green colour in this case.
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The Right flask, if further iodine solution were to be added, the solution's green colour would become darker as shown, due to the formation of further iodine-______ complex.
The Right flask, if further iodine solution were to be added, the solution's green colour would become darker as shown, due to the formation of further iodine-______ complex.
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