【11.12-18 Weekly Question】+3 points for participation, +4~17 points for correct answer
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This post was last edited by pay_modem on 2015-11-13 at 13:19. Multiple-choice question: The decremental weighing method is most suitable for weighing ( ). A. Substances that are corrosive to balances B. Highly toxic substances C. Substances that are prone to deliquescence, absorption of CO2, or oxidation D. Volatile substances. Correct answer: C
C. Substances that are hygroscopic, prone to absorbing CO2, or susceptible to oxidation – The weight-reduction method: also known as the decrement weighing method. This approach is used for weighing substances that absorb water easily, oxidize readily, or react with CO2. There is no need for a fixed value regarding the mass of the sample; it only needs to fall within the specified weighing range. An appropriate amount of the sample is placed in a dry and clean weighing flask. A clean piece of paper is wrapped around the flask, and the flask is placed on the balance pan to determine its mass m1. The flask is then removed, the lid is taken off the container holding the sample, the flask is tilted, and the lid is used to tap the opening of the flask so that the sample slowly falls into the container. When the desired weight is nearly reached, the lid is again tapped to cause any remaining sample stuck to the opening to fall out. The flask is then slowly turned upright, the lid is put back on, and its mass m2 is measured. The difference between these two masses represents the mass of the first portion of sample that has been transferred into the container. This method can be used to obtain multiple portions of sample in this way.
The decreasing weighing method is most suitable for weighing (C)
C. Substances that are hygroscopic, prone to absorbing CO2, or susceptible to oxidation.....................
C. Substances that are hygroscopic, prone to absorbing CO2, or susceptible to oxidation
C. Substances that are hygroscopic, prone to absorbing CO2, or susceptible to oxidation
C. Substances that are hygroscopic, prone to absorbing CO2, or susceptible to oxidation
The decrement weighing method is most suitable for weighing substances that are prone to deliquescence, absorption of CO2, or oxidation
The decreasing weighing method is most suitable for weighing (C) A. Substances that are corrosive to balances B. Highly toxic substances C. Substances that are hygroscopic, prone to absorbing CO2, or easy to oxidize D. Volatile substances
C. Substances that are hygroscopic, prone to absorbing CO2, or susceptible to oxidation
The decrement weighing method is most suitable for weighing (C) A. Substances that are corrosive to balances B. Highly toxic substances C. Substances that are hygroscopic, prone to absorbing CO2, or easily oxidized D. Volatile substances