Answer:
The molarity of a solution is 2.5 M
Explanation:
Molarity is a concentration unit that describes how much of a solution is dissolved in solution.
Molarity of a solution can found by using the formula,
Molarity (M) = (moles of solute)/(Liters of Solution).
Given, mass of Sodium = 114.95 grams.
Volume of water = 2 L.
Here, Sodium is solute as it is dissolved in water, which is the solvent.
Moles of Sodium(solute) can be found by using the formula,
Number of Moles = mass/Molecular weight.
mass of Sodium = 114.95 grams.
Molecular weight = 22.989 grams
Number of Moles of Sodium(solute) =114.95/22.989 = 5.
Substituting the values in the formula, we get,
M = 5/2 = 2.5 M
Answer:
Ai --> Bii
Aii --> Bi
Aiii --> Bv
Aiv --> Biii
Av --> Biv
Explanation:
For Ai, naphthalene sublimes directly from a solid to gas when heated at around 80 degree Celsius.
For Aii, Ozone has a molecular formula of O₃.
For Aiii, weeds are normally considered as "unwanted" plants. Many people may consider using herbicides to clear the weeds in their gardens.
For Aiv, filtration is a physical method for separating solid and liquid from a mixture. A filter paper is normally used, in which the complex structure of the paper only allows fluid to pass through it, but not the solid ones. The solid left behind on the filter paper is called "residue".
For Av, photosynthesis is a chemical reaction that occurs in the leaves of a plant, which produces food for plants to survive. Carbon dioxide, water and light are required for photosynthesis to take place.
Answer:Cell reaction is going forward.
Explanation:
For any chemical reaction to be spontaneous or to move in forward direction the ΔG ,the Gibbs free energy must be negative.
The cell potential of a battery is positive for a spontaneous reaction, so for a battery to give output its cell potential must be positive.
Thermodynamics and electro-chemistry are related in the following manner:
ΔG=-nFE
n=number of electrons involved
F=Faradays constant
E=cell pottential of battery
so from the above equation ΔG would only be negative when E cell that is the cell potential is positive.
For a battery which is being used its cell potential is positive and hence the ΔG would be negative. So the cell reaction occurring would be in forward direction as ΔG is negative.
when the cell potential Ecell is 0 then ΔG is also zero then the reaction occurring in battery would be at equilibrium.
When the cell potential Ecell is - then ΔG is positive and the reaction would be occurring backwards.
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.
“Water” is the best thermal insulator.
Option: B
<u>Explanation</u>:
“Thermal insulators” are the materials which do not allow heat to transfer. “Water” is the substance which does not transfer heat. Hence, the “water” is the best “thermal insulator”. Water is the bad conductor of thermal heat. Water has “low thermal conductivity” than other substances, so this acts as an insulator as long as it is not traveled from one place to another. Heat is transferred when a “hot object collides” with “the cold objects”. The “thermal conductivity” of “water” is 0.6 W/m K.
