The heat used in phase changes is calculated by multiplying the mass of the substance by the energy of the phase change. In this case, for liquid to boil, we would find total heat by multiply the mass of liquid by the latent heat of vaporization (Hvap). If we are instead given the Hvap and the total heat of 1 kJ, we would divide 1 kJ by the Hvap (which is usually in kJ/kg) to get the mass of liquid boiled (in kg).
Answer:
Fe
Explanation:
The cell potential is:
ΔE°cell = E°red(red) - E°red(oxid)
Where, E°red(red) is the reduction potential of the substance that is reducing, and E°red(oxid) is the reduction potential of the substance that is oxidizing. For the reaction be spontaneous and happen, ΔE°cell > 0.
The reduction takes place in the cathode, which is the negative pole, and the oxidation in the anode, which is the positive pole. So, the electrons flow from the positive pole to the negative pole (anode to cathode).
Then, if the voltmeter measured a negative potential, it means that is was attached incorrectly. So, the anode is Fe.
Answer : Option C) 0.3 mol of Gold.
Explanation : Amongst the options given in the question, 0.3 mol of Au is the greatest in mass in grams.
As 0.3 mol X atomic weight of Au (196.966) = 59.088 grams;
Silver has 0.5 mol X atomic weight of Ag (107.86) = 53.93 grams;
The other options are not relevant as they deal in the atomic range which has mass value very less as compared to the moles of elements.
Therefore, it is clear that Au has the greatest mass amongst the given choices.
Explanation:


The above two reactions xcan also be written in form of single chemcial equation:
![FeCl_3+K(SCN)\rightleftharpoons KCl+[Fe(SCN)]Cl_2(blood-red)](https://tex.z-dn.net/?f=FeCl_3%2BK%28SCN%29%5Crightleftharpoons%20KCl%2B%5BFe%28SCN%29%5DCl_2%28blood-red%29)
1. Color of ferric chloride solution is yellow. This is due to presence of ferric ions which have yellow color in their aqueous solutions.
2. KSCN has the colorless solution. This due to potassium ion forms colorless aqueous solution.
3. On mixing, KSCN with
we will get blood red color solution of
.
Answer:
The correct answer is option 3.
Explanation:

The expression of
is given by :
![K_w=[H^+][OH^-]](https://tex.z-dn.net/?f=K_w%3D%5BH%5E%2B%5D%5BOH%5E-%5D)
![K_w\propto [H^+]](https://tex.z-dn.net/?f=K_w%5Cpropto%20%5BH%5E%2B%5D)
![K_w\propto [OH^-]](https://tex.z-dn.net/?f=K_w%5Cpropto%20%5BOH%5E-%5D)
Rise in temperature will result in more dissociation of water molecules into hydrogen ions and hydroxide ions.
With an increase in concentration of hydrogen ions and hydroxide ions value of
will also increase.