Answer: 
for the reaction 
is -108kJ
Explanation:
The balanced chemical reaction is,
The expression for enthalpy change is,
![\Delta H=[n\times B.E_{reactants}]-[n\times B.E{products}]](https://tex.z-dn.net/?f=%5CDelta%20H%3D%5Bn%5Ctimes%20B.E_%7Breactants%7D%5D-%5Bn%5Ctimes%20B.E%7Bproducts%7D%5D)
where, n = number of moles
Now put all the given values in this expression, we get
![\Delta H=[1\times B.E_{Cl_2}+1\times B.E_{F_2}]-[2\times B.E_{ClF}]](https://tex.z-dn.net/?f=%5CDelta%20H%3D%5B1%5Ctimes%20B.E_%7BCl_2%7D%2B1%5Ctimes%20B.E_%7BF_2%7D%5D-%5B2%5Ctimes%20B.E_%7BClF%7D%5D)
![\Delta H=[(1\times 243)+(1\times 159)]-[2\times 255]](https://tex.z-dn.net/?f=%5CDelta%20H%3D%5B%281%5Ctimes%20243%29%2B%281%5Ctimes%20159%29%5D-%5B2%5Ctimes%20255%5D)
Thus for the reaction is -108kJ
Living organisms contain relatively large amounts of oxygen, carbon, hydrogen, nitrogen, and sulfur (thesefive elements are known as the bulk elements), along with sodium, magnesium, potassium, calcium, chlorine, and phosphorus (these six elements are known as macrominerals).
Molality= moles NaCl/ Kg H2O
250 g (1 Kg/ 1000 grams)= 0.250 Kg
Molality= 0.611 moles/ 0.250 Kg= 2.44 molal
Answer:
Argon has 8 valence electrons making it non reactive.
Explanation:
Reactive chemicals are store in containers filled with Argon gas because the argon gas is non reactive. This is true because the argon gas has completely filled octet structure.
This can further be explained by writing the electronic configuration of argon.
The electronic configuration of argon is given below:
Ar (18) => 1s² 2s²2p⁶ 3s²3p⁶
Valence electron => 3s²3p⁶ = 2 + 6 = 8
From the above illustration, we can see that the outermost shell (i.e 3s²3p⁶) is having 8 electrons indicating that it is completely filled as the maximum number of electrons any shell can accommodate outside the first shell is 8 electrons. Thus, argon has 8 valence electrons ( i.e electrons in the outermost shell) and hence it is non reactive as the outermost shell is completely filled.
