Answer:
<h3>The answer is 11 g/cm³</h3>
Explanation:
The density of a substance can be found by using the formula

From the question
mass = 2.75 kg = 2750 g
volume = 250 cm³
We have

We have the final answer as
<h3>11 g/cm³</h3>
Hope this helps you
Answer : The activation energy for the reaction is, 43.4 KJ
Explanation :
According to the Arrhenius equation,

or,
![\log (\frac{K_2}{K_1})=\frac{Ea}{2.303\times R}[\frac{1}{T_1}-\frac{1}{T_2}]](https://tex.z-dn.net/?f=%5Clog%20%28%5Cfrac%7BK_2%7D%7BK_1%7D%29%3D%5Cfrac%7BEa%7D%7B2.303%5Ctimes%20R%7D%5B%5Cfrac%7B1%7D%7BT_1%7D-%5Cfrac%7B1%7D%7BT_2%7D%5D)
where,
= rate constant at 
= rate constant at
= 
= activation energy for the reaction = ?
R = gas constant = 8.314 J/mole.K
= initial temperature = 
= final temperature = 
Now put all the given values in this formula, we get:
![\log (\frac{3K_1}{K_1})=\frac{Ea}{2.303\times 8.314J/mole.K}[\frac{1}{291K}-\frac{1}{310K}]](https://tex.z-dn.net/?f=%5Clog%20%28%5Cfrac%7B3K_1%7D%7BK_1%7D%29%3D%5Cfrac%7BEa%7D%7B2.303%5Ctimes%208.314J%2Fmole.K%7D%5B%5Cfrac%7B1%7D%7B291K%7D-%5Cfrac%7B1%7D%7B310K%7D%5D)

Therefore, the activation energy for the reaction is, 43.4 KJ
Water vapor is moisture in the air or humidity, they results from the evaporation of water, it also traps heat, and condenses to make clouds. Water vapor is water in its gaseous state instead of liquid or solid . It is extremely important to the weather and climate.