The concentration of hydrogen can be shown as:
[H+ ] = 3 * 10-5 M
pH can be determined as:
pH = - log [H+ ]
= - log (3 * 10-5)
= 4.53
Thus the pH of solution is 4.53
Answer:
Reaction 5: Decomposition reaction.
Reaction 6: Single replacement reaction
Reaction 7: Combination reaction.
Reaction 8: Combustion reaction.
Explanation:
<u><em>Reaction 5:</em></u> 2KClO₃ → 2KCl + 3O₂.
- It is a decomposition reaction.
- A decomposition reaction is a type of chemical reaction in which a single compound breaks down into two or more elements or new compounds.
- In this reaction: potassium chlorate decomposes into two single components (potassium chloride and oxygen).
- So, it is a decomposition reaction.
<u><em>Reaction 6:</em></u> Zn + 2HCl → H₂ + ZnCl₂.
- It is a single replacement reaction.
- A single-replacement reaction, a single-displacement reaction, is a reaction by which one (or more) element(s) replaces an/other element(s) in a compound.
- It is most often occur if element is more reactive than the other, thus giving a more stable product.
- In this reaction, zinc metal (more active) displaces the hydrogen to form hydrogen gas and zinc chloride, a salt. Zinc reacts quickly with the acid to form bubbles of hydrogen.
<u><em>Reaction 7:</em></u> N₂O₅ + H₂O → 2HNO₃.
- It is a combination "synthesis" reaction.
- A synthesis reaction has two or more reactants and only one product.
- In this reaction, dinitrogen pentoxide reacts with water to produce nitric acid.
- So, it is considered as a synthetic "combination" reaction.
<u><em>Reaction 8:</em></u> 2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O.
- It is a combustion reaction.
- A combustion reaction is a reaction where hydrocarbon alkane is completely burned in oxygen to produce water and carbon dioxide.
- In this reaction 1.0 mole of ethane is burned to give 4.0 moles of carbon dioxide and 6.0 moles of water.
- So, it is considered as a combustion reaction.
True energy passes from animal to animal or plant to plant
We will use boiling point formula:
ΔT = i Kb m
when ΔT is the temperature change from the pure solvent's boiling point to the boiling point of the solution = 77.85 °C - 76.5 °C = 1.35
and Kb is the boiling point constant =5.03
and m = molality
i = vant's Hoff factor
so by substitution, we can get the molality:
1.35 = 1 * 5.03 * m
∴ m = 0.27
when molality = moles / mass Kg
0.27 = moles / 0.015Kg
∴ moles = 0.00405 moles
∴ The molar mass = mass / moles
= 2 g / 0.00405 moles
= 493.8 g /mol
