The constant used for the absorption of heat by the sample in melting is 
. Thus, option A is correct.
The chemical reaction has been defined as the energy in which the energy has been released or absorbed for the breaking of bonds in the reactants and the formation of product.
<h3>Constant for energy absorbed</h3>
The energy has been absorbed in the melting of the copper sample. Thus, the sample has been converted from the solid to the liquid state.
The change in energy with the conversion in solid and liquid state has been termed as heat of fusion.
The energy has been absorbed by the system, thus it has been marked with the positive sign.
Therefore, has been the constant used for the absorption of heat by the sample in melting. Thus, option A is correct.
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Explanation:
Let us assume that the given data is as follows.
V = 3.10 L, T = 
= (19 + 273)K = 292 K
P = 40 torr (1 atm = 760 torr)
So, P = 
= 0.053 atm
n = ?
According to the ideal gas equation, PV = nRT.
Putting the given values into the above equation to calculate the value of n as follows.
PV = nRT
0.1643 = 
n = 
It is known that molar mass of ethanol is 46 g/mol. Hence, calculate its mass as follows.
No. of moles = 
mass = 
g
= 0.315 g
Thus, we can conclude that the mass of liquid ethanol is 0.315 g.
The correct answer is 
.
<h3>Organometallic reagent</h3>
Organometallic chemistry is the study of organometallic compounds, which are substances that contain at least one chemical bond between a carbon atom from an organic molecule and a metal. These substances include alkali, alkaline earth, and transition metals, as well as metalloids like boron, silicon, and selenium. In addition to links to organyl fragments or molecules, bonds to 'inorganic' carbon, such as those to carbon monoxide (metal carbonyls), cyanide, or carbide, are also typically regarded as organometallic. Although they are not strictly speaking organometallic compounds, some similar compounds, such as transition metal hydrides and metal phosphine complexes, are frequently included in discussions of such substances. The phrase "metalorganic compound," which is comparable but different, describes molecules that contain metals but do not have direct metal-carbon bonds but do have organic ligands.
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Explanation:
molarity = no. of moles of solute/solution in litres
molarity =0.202/7.98
=0.025 M
