Answer : The activation energy for the reaction is, 51.9 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 295 K
= rate constant at 305 K = 
Ea = activation energy for the reaction = ?
R = gas constant = 8.314 J/mole.K
= initial temperature = 295 K
= final temperature = 305 K
Now put all the given values in this formula, we get:
![\log (\frac{2K_1}{K_1})=\frac{Ea}{2.303\times 8.314J/mole.K}[\frac{1}{295K}-\frac{1}{305K}]](https://tex.z-dn.net/?f=%5Clog%20%28%5Cfrac%7B2K_1%7D%7BK_1%7D%29%3D%5Cfrac%7BEa%7D%7B2.303%5Ctimes%208.314J%2Fmole.K%7D%5B%5Cfrac%7B1%7D%7B295K%7D-%5Cfrac%7B1%7D%7B305K%7D%5D)

Therefore, the activation energy for the reaction is, 51.9 kJ
Chromium and copper (ii) sulfate react according the reaction below;
2Cr + 3CuSO4 = 3Cu +Cr2(SO4)3
We can calculate the number of moles of CuSO4 present;
no of moles of CuSO4 = 0.75 × 0.125 = 0.09735 moles
According to the reaction the mole ratio is 2 : 3
Moles of Chromium = (0.09735 × 2)/3
= 0.0625 Moles
Mass of chromium = 0.0625 moles × 52 g/mole
= 3.25 g of chromium
<span>The law of conservation of mass applies to all chemical reaction, so this means that there was equal mass before and after the reaction. However, if the mass has decreased, then it means there has been a loss of substance. The most common cause of this is the liberation of gases from a chemical reaction mixture, the mass of which is not measured by the scale.</span>
Answer:
Same number of electrons and the same chemical reactivity.
Answer:
See Explanation
Explanation:
The rate of a chemical reaction depends on certain factors. Some of these factors include; surface area, temperature, nature of reactants etc.
The trial that exhibits the slowest rate of dissolution of CuSO4 crystals is trial 2 because the crystals have a small surface area since the crystals were large. Also, the solution was not agitated or stirred to increase the rate of collision between the water and the CuSO4 crystals.
Increase in temperature, agitation of the reaction solution and high surface area increases the rate of collision between the water and CuSO4 crystals leading to a faster rate of dissolution. This occurs in trial 3.