Answer:
density=1.43 g/L
Explanation:
Since the density formula is density = mass / volume, we need to find out the mass of the gas and the volume is that of the container.
The mass of the gas is 130.0318 g-129.6375 g=0.3943 g
The gas volume is 276mL*(1L/1000mL) 0.276 L
density = mass / volume=0.3943g/0.276L
density =1.43g/L
From the calculation, the moles of water produced is 18 moles of water.
<h3>What is a decomposition reaction?</h3>
A decomposition reaction is one in which a substance is split up into smaller parts.
We have the reaction; 2 Cr(OH)3(aq) ------------> Cr2O3(s) + 3H2O(l)
From this reaction;
2 moles of Cr(OH)3 produced 3 moles of water
12 moles of Cr(OH)3 will produce;
12 moles * 3 moles / 2moles
= 18 moles of water
Hence, 12 moles of chromium (III) hydroxide produces 18 moles of water.
Learn more about decomposition reaction:brainly.com/question/8009068?
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Answer : The equilibrium concentration of
in the solution is, 
Explanation :
The dissociation of acid reaction is:

Initial conc. c 0 0
At eqm. c-x x x
Given:
c = 

The expression of dissociation constant of acid is:
![K_a=\frac{[H_3O^+][C_6H_5COO^-]}{[C_6H_5COOH]}](https://tex.z-dn.net/?f=K_a%3D%5Cfrac%7B%5BH_3O%5E%2B%5D%5BC_6H_5COO%5E-%5D%7D%7B%5BC_6H_5COOH%5D%7D)

Now put all the given values in this expression, we get:
![6.3\times 10^{-5}=\frac{(x)\times (x)}{[(7.0\times 10^{-2})-x]}](https://tex.z-dn.net/?f=6.3%5Ctimes%2010%5E%7B-5%7D%3D%5Cfrac%7B%28x%29%5Ctimes%20%28x%29%7D%7B%5B%287.0%5Ctimes%2010%5E%7B-2%7D%29-x%5D%7D)

Thus, the equilibrium concentration of
in the solution is, 