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 :
Option D) 2.50 X
Mol/(L s)
Explanation: While calculating the average reaction rate for the given reaction in terms of Cl;

.
using the rate equation which is;

![\frac{delta [Cl]}{delta t}](https://tex.z-dn.net/?f=%20%5Cfrac%7Bdelta%20%5BCl%5D%7D%7Bdelta%20t%7D%20)
=

=
2.50 X
Mol/(L s)
Answer:
Q = 25360.269 j
Explanation:
Given data:
Mass = 165 g
Initial temperature = 10.55 °C
Final temperature = 47.32°C
Energy absorbed = ?
Solution:
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
ΔT = T2 - T1
ΔT = 47.32°C - 10.55 °C
ΔT = 36.77 °C
Q = m.c. ΔT
Q = 165 g . 4.18 j/g.°C . 36.77 °C
Q = 25360.269 j
2F⁻ → F₂ + 2e⁻
(mainly electrochemical oxidation)