Answer:- C. Hafnium.
Solution:- Mass of the sample is 46.0 g and it's volume is 
.
From mass and volume, we can calculate it's density using the formula:
On the basis of the density, this substance could either be mercury or hafnium. Since the substance is a solid at room temperature where as mercury is liquid. So, it can't be mercury.
The right choice is C) Hafnium.
Answer:
No, they don't because of fact some way more than the other even if it's the same type of element.
Explanation:
There are two types of element weight I think.
Answer : The total change in enthalpy of this reaction is 25 kJ.
Explanation :
Enthalpy of reaction : It is defined as the changes in heat energy takes place when reactants go to products. It is denotes as .
ΔH = Energy of product - Energy of reactant
ΔH is positive when heat is absorbed and the reaction is endothermic.
ΔH is negative when heat is released and the reaction is exothermic.
In the given potential energy diagram, the energy of product at higher level and energy of reactant at lower level. The ΔH for this reaction will be positive.
Given:
Energy of product = 55 kJ
Energy of reactant = 30 kJ
ΔH = Energy of product - Energy of reactant
ΔH = 55 kJ - 30 kJ
ΔH = 25 kJ
Thus, the total change in enthalpy of this reaction is 25 kJ.
