Some solid CaO in a test tube picks up water vapor from the surroundings to change
completely to Ca(OH). An observed total initial weight (CaO + test tube) of 10.860 g
goes eventually to 11.149 g. What is the weight of the test tube?
CaO + H2O ==< Ca(OH)2
11.149 g = TT + CaO + H2O
-10.860 g = TT + CaO
-----------
0.289 g = H2O added.
Using stoichiometry, convert g H2O tog CaO. Then
10.860 g = TT + CaO
-xxxxxx g = CaO
----------
xxxxxxx g = TT
Post your work if you get stuck.
Well, it looks like our solid CaO had a bit of an identity crisis and decided to become Ca(OH). I guess it saw the water vapor and thought, "I want to be a hydroxide too!" Talk about peer pressure.
Now, to solve the mystery of the weight of the test tube. We had an initial weight of 10.860 g, and it went up to 11.149 g. So, the change in weight is 11.149 g - 10.860 g = 0.289 g.
Since we know this weight includes both the Ca(OH) and the test tube, we need to find out how much of it is the test tube alone. It's like playing a game of "hide and seek" with the test tube.
Unfortunately, I can't directly tell you the weight of the test tube without some further information. You see, the Ca(OH) and the test tube are kinda like partners in crime here, and I can't separate them without more details.
But hey, don't be too sad! I hope I at least brought a smile to your face with my clown-like explanation.
To find the weight of the test tube, we can subtract the weight of CaO from the total initial weight.
Weight of CaO = 11.149 g - 10.860 g = 0.289 g
Since the weight of the test tube is the total initial weight minus the weight of CaO, we can calculate it as follows:
Weight of test tube = Total initial weight - Weight of CaO
= 10.860 g - 0.289 g
= 10.571 g
Therefore, the weight of the test tube is 10.571 g.
To find the weight of the test tube, we need to calculate the weight of Ca(OH) formed in the reaction.
First, we need to determine the change in weight of CaO during the reaction. This can be calculated by subtracting the final weight of CaO from the initial weight of CaO:
Change in weight of CaO = Final weight of CaO - Initial weight of CaO
Final weight of CaO = 11.149 g
Initial weight of CaO = 10.860 g
Change in weight of CaO = 11.149 g - 10.860 g
Change in weight of CaO = 0.289 g
Now, we need to recognize that the stoichiometry of the reaction is 1:1 between CaO and Ca(OH)2. This means that for every gram of CaO reacted, 1 gram of Ca(OH)2 is formed.
Since the change in weight of CaO is equal to the weight of Ca(OH)2 formed, we can conclude that the weight of the test tube is also equal to the change in weight of CaO:
Weight of test tube = Change in weight of CaO = 0.289 g
Therefore, the weight of the test tube is 0.289 g.