Carbon-14 is the typical radioisotope used to date materials; however it has limitation to 40000 years a scientist who wants to
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Answer:
C. pH values are different because the solution partially ionizes and the HCl solution ionizes 100 percent.
Explanation:
Strong acids are the acids which completely ionizes in the solution while weak acids are the acids which ionizes partially in the solution. They exists in equilibrium in the solution with their respective ions.
Thus, strong acids furnish greater concentration of protons as compared to weak acid when same concentration of both types are taken.
<u>Also, pH is the negative of the logarithm of the hydrogen ions. Thus, hydrogen ion concentration for both acids are different and thus pH will be different.</u>
A reaction is exothermic if Δ<em>H</em> (or in some textbooks) is negative:
- H₂ + Br → 2 HBr, ΔH < 0.
- CH₄ + 2 O₂ → CO₂ + 2 H₂O, ΔH < 0.
A reaction is endothermic if Δ<em>H</em> is positive:
- 2 NH₃ → N₂ + 3 H₂, ΔH > 0.
- 2 HCl → H₂ + Cl₂ ΔH > 0.
The enthalpy of a system is the sum of its internal energy. ΔH < 0 indicates that the reactants lose internal energy in the reaction. Energy conserves, and those internal energies must have converted to some other form of energy. They typically end up as thermal energy. The reaction will release heat since it is exothermic.
Similarly, ΔH > 0 indicates that the reactants gains internal energy in the reaction. Energy conserves. As a result, the reaction must have gained energy from its surroundings. The reaction will be endothermic since it absorbs heat.