Half life is defined as the time when the final concentration reduced to half of the initial value.
Thus, for first half life, the remaining percentage of the reactant is 50 percent that is 
Now, for second half life, the remaining percentage will be 50 percent of the remaining 50 percentage that is 
or 
Thus, general formula for n half lives =
Now, 98.4 years is equal to eighth times 12.3 years that is 
=
remaining material.
Therefore, mass of the nuclide will remain after 98.4 years= 
= 
Mass of remaining nuclide after 98.4 years =
I’d say probably a forest
<span>D) Two electrons are shared between each hydrogen atom and the carbon atom bonded to it, and four electrons are shared between the carbon atoms.
I HOPE THIS HELPS :)</span>
Answer:
Explanation:
2Al(s) + Fe₂O₃(s) ⟶ Al₂O₃(s) + 2Fe(s); ΔᵣH = ?
The formula for calculating the enthalpy change of a reaction by using the enthalpies of formation of reactants and products is
2Al(s) + Fe₂O₃(s) ⟶ Al₂O₃(s) + 2Fe(s)
ΔfH°/kJ·mol⁻¹: 0 -824.3 -1675.7 0
![\begin{array}{rcl}\Delta_{\text{r}}H^{\circ} & = & [1(-1675.7) + 2(0)] - [2(0) - 1(-824.3)]\\& = & -1675.7 + 824.3\\& = & \textbf{-851.4 kJ/mol}\\\end{array}\\\text{The enthalpy change is } \large \boxed{\textbf{-851.4 kJ/mol}}](https://tex.z-dn.net/?f=%5Cbegin%7Barray%7D%7Brcl%7D%5CDelta_%7B%5Ctext%7Br%7D%7DH%5E%7B%5Ccirc%7D%20%26%20%3D%20%26%20%5B1%28-1675.7%29%20%2B%202%280%29%5D%20-%20%5B2%280%29%20-%201%28-824.3%29%5D%5C%5C%26%20%3D%20%26%20-1675.7%20%2B%20824.3%5C%5C%26%20%3D%20%26%20%5Ctextbf%7B-851.4%20kJ%2Fmol%7D%5C%5C%5Cend%7Barray%7D%5C%5C%5Ctext%7BThe%20enthalpy%20change%20is%20%7D%20%5Clarge%20%5Cboxed%7B%5Ctextbf%7B-851.4%20kJ%2Fmol%7D%7D)
Answer:Two Main Types of Pure Substances
Elements and compounds are the two types of pure substances. Examples of common elements include carbon, nitrogen and hydrogen. They consist of one type of atom and cannot break down into something else. Every pure carbon substance, for example, has the same particles in it.
Explanation:I think
