Answer:
Molecules are speeding up during boiling
Explanation:
According to the kinetic theory of matter, matter exists in three states; solid, liquid and gas. In the solid state, the molecules of a substance are in fixed positions, the can only vibrate but can not translate. In the liquid state, the molecules acquire a greater degree of freedom and can translate in addition to vibration and rotation. In a gas the molecules are infinitely free and translate at high velocities.
Arrow 1 shows a phase change from liquid to gas. This occurs during boiling. This phase change is possible because the liquid molecules acquire energy in the form of heat supplied during boiling thereby making the molecules of the liquid to speed up their motion and escape the liquid surface as vapour.
Answer:
a. absorbs energy as heat and has positive enthalpy of solution.
Explanation:
A reaction can either be exothermic or endothermic. An endothermic reaction, as the dissolution described in the question, is that which absorbs heat energy from the surroundings in order to start the reaction.
Because an endothermic reaction makes heat lost from the surroundings, the enthalpy (∆H) of the solution will be positive (+). ∆H is got by finding the difference between the enthalpy of the reactants and products and since the enthalpy of a product in endothermic reaction is more, the enthalpy change (∆T) will be positive.
<span>Zn⁰ + 2H⁺ ------> Zn²⁺ + H2⁰
H⁺ ion has oxidation number +1.
Zn²⁺ ion has oxidation number +2.
Atom of Zn has electric charge 0, and each hydrogen atom in the molecule H2 have oxidation number 0. So, </span> Zn and each hydrogen atom in H2 have oxidation numbers equals "0".<span>
</span><span>Answer is
D. Zn and each hydrogen atom in H2</span><span>
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