鹼石灰吸收了二氧化碳後質量會否增加？

Hi Kathy, as for your 1) answer, I am quite agree with you but not so for the 2) answer.

1) The increase in the 鹼石灰 is due to the digestion of glucose by yeast getting rise to the by-product CO2 which will finally react with the 鹼石灰 to give rise to a reaction products which has larger weight than the original starting material.
(CaO + CO2 = CaCO3 ; 2NaOH + CO2 = Na2CO3 + H2O) So, by calculating the difference in weight that you can calculate the rate of reaction of yeast and glucose.

2) There may be two possible scenerios:
i - 鹼石灰與二氧化碳的反應 maybe ENDOTHERMIC that the heating of the 鹼石灰will boost the reaction of 鹼石灰 with atomospheric CO2;
ii- the heating of 鹼石灰 may lead to decomposition of 鹼石灰 itself which gives rise to the products which is heavier then the starting materials themselves.

This is my own interpretation. I look forward to hearing further discussions from you guys! :)

2007-12-02 02:43:27 補充：
Ca(OH)2 (heat) → CaO H2O

2007-12-02 02:53:05 補充：
I finally found that 鹼石灰與二氧化碳的反應 is an exothermic reaction. Thus, all the problems are solved. The first 鹼石灰put in 冰箱 is to show that there is no 鹼石灰與二氧化碳的反應 under this condition and so no/not significant increase in mass.

2007-12-02 02:53:18 補充：
As for the 熱水浴, there is atmospheric CO2 absorbed by the 鹼石灰 and hence increase in weight.

2007-12-02 02:53:59 補充：
Soda lime is used in breathing systems to absorb expired CO2 during anaesthesia. It can be incorporated in a Mapleson C system or a circle system. The reaction:CO2 H2O leads to H2CO32H2CO3 2NaOH leads to Na2CO3 4H2O Heat2Ca(OH)2 Na2CO3 leads to 2CaCO3 2NaOH Heat

1. the yeast carry out respiration and give out CO2(二氧化碳). the lime stone(鹼石灰) absorbed the CO2 and thus its weight increased.
the weight increased = the weight of CO2 absorbed.
so u can calculate how much CO2 is absorbed by knowing the mass increased of the lime stone.

2. it really depends on how hot is the water bath...if the water bath is so hot that it kills all the yeast, then no respiration could be carried out and all absorbed CO2 is from the air inside the jars.
if it's not so hot and some yeast survives, then the CO2 is given out by the yeast survived.