If temperature is increased, what happens to the rate of diffusion?
The rate of diffusion increases.
The change in rate of diffusion is unaffected.
Diffusion halts.
The change in rate of diffusion is unpredictable.
The Correct Answer is A
Choice A rationale: The rate of diffusion is the speed at which particles move from an area of high concentration to an area of low concentration. This depends on the temperature, the size of the particles, and the medium they are in. Temperature affects the kinetic energy and the speed of the particles, which in turn affects the frequency and intensity of their collisions. Higher temperatures mean higher kinetic energy and faster particles, which leads to faster diffusion. ³
Choice B rationale: The change in rate of diffusion is not unaffected by temperature. Temperature is one of the main factors that influences the rate of diffusion, as explained above. Therefore, this choice is incorrect.
Choice C rationale: Diffusion does not halt when temperature is increased. On the contrary, diffusion becomes faster when temperature is increased, as explained above. Therefore, this choice is incorrect.
Choice D rationale: The change in rate of diffusion is not unpredictable when temperature is increased. There is a clear relationship between temperature and diffusion, as explained above. Therefore, this choice is incorrect.
Choice E rationale: The rate of diffusion does not decrease when temperature is increased. On the contrary, diffusion becomes faster when temperature is increased, as explained above. Therefore, this choice is incorrect..
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is B
Explanation
Choice A rationale: Sudan IV is a stain used to stain lipids. It is a red powder that dissolves in lipids and stains them red, but does not react with sugars. ¹
Choice B rationale: Benedict's is a reagent used to test for reducing sugars. It is a blue solution of copper (II) sulfate, sodium carbonate, and sodium citrate that reduces the copper (II) ions to copper (I) ions when heated with a reducing sugar, forming a red, orange, or green precipitate of copper (I) oxide. ⁴
Choice C rationale: Biuret is a reagent used to test for proteins and polypeptides. It is a blue solution of copper (II) sulfate and sodium hydroxide that forms a violet or pink complex with the peptide bonds in proteins or peptides. ⁸
Choice D rationale: Phenol red is a pH indicator. It is a red solution that changes color from yellow to red over the pH range 6.8 to 8.2, and from pink to fuchsia over 8.2 to 10.0. It does not react with sugars. ¹¹
Choice E rationale: Iodine is a reagent used to test for starch. It is a brown solution of iodine and potassium iodide that forms a blue-black complex with the starch molecules. It does not react with simple sugars. ¹⁴
Correct Answer is E
Explanation
Choice A rationale: Albumin solution is not a negative control, but a positive control for the test for protein. Albumin is a type of protein that reacts with the biuret reagent and produces a violet color. A positive control is used to confirm that the test works and gives a positive result when the substance is present³.
Choice B rationale: Starch solution is not a negative control, but a positive control for the test for starch. Starch is a type of carbohydrate that reacts with the iodine solution and produces a blue-black color. A positive control is used to confirm that the test works and gives a positive result when the substance is present³.
Choice C rationale: Glucose solution is not a negative control, but a positive control for the test for sugar. Glucose is a type of sugar that reacts with the Benedict's solution and produces a red-orange color. A positive control is used to confirm that the test works and gives a positive result when the substance is present³.
Choice D rationale: Olive oil is not a negative control, but a positive control for the test for lipids. Olive oil is a type of lipid that reacts with the Sudan III solution and produces a red color. A positive control is used to confirm that the test works and gives a positive result when the substance is present³.
Choice E rationale: Distilled water is a negative control for the tests for protein, lipids, sugars, and starch. Distilled water is a pure solvent that does not contain any of these substances. It does not react with any of the reagents and does not produce any color change. A negative control is used to confirm that there is no response to the reagent or the microorganism used in the test. It is used to set the baseline and verify that the detecting reagent is working properly³.
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