A solution (in this experiment solution of NaNO₃) freezes at a lower temperature than does the pure solvent (deionized water). The higher the
solute concentration (sodium nitrate), freezing point depression of the solution will be greater.
Equation describing the change in freezing point:
ΔT = Kf · b · i.
ΔT - temperature change from pure solvent to solution.
Kf - the molal freezing point depression constant.
b - molality (moles of solute per kilogram of solvent).
i - Van’t Hoff Factor.
First measure freezing point of pure solvent (deionized water). Than make solutions of NaNO₃ with different molality and measure separately their freezing points. Use equation to calculate Kf.
Answer:
2.12 moles of gas were added.
Explanation:
We can solve this problem by using<em> Avogadro's law</em>, which states that at constant temperature and pressure:
Where in this case:
We <u>input the data</u>:
- 6.13 L * n₂ = 11.3 L * 2.51 mol
As <em>4.63 moles is the final number of moles</em>, the number of moles added is:
Answer:
Valence electrons are involved in Reaction B but not in Reaction A.
Explanation:
The description of reaction A in which protons are lost or gained by the atom of the element is a nuclear reaction. In nuclear reactions, the nucleons which are the protons and neutrons drives the reaction. No valence electrons in the orbiting shells are involved in this kind of reaction. During this type of reaction, an atom changes it identity to that of another.
Reaction B in which no identity change occurs is a chemical reaction. In chemical reactions bonds are formed by the atoms using the valence electrons that orbits round the central nucleus. The atoms remain the same but it chose to attain stability and an inert configuration by losing or gaining electrons.
The balanced equation for the decomposition of solid lead iv oxide is as follows: 2PbO2 = 2PbO + O2.
Lead IV oxide decompose to give lead ll oxide and oxygen. Lead iv oxide is thermally unstable and it usually decomposes into oxygen and lead ll oxide when heated. Lead ll oxide is more stable than lead lV oxide.
If these are you choices:
(1) Both the solid and the liquid are good conductors.
(2) Both the solid and the liquid are poor conductors.
(3) The solid is a good conductor, and the liquid is a poor conductor.
(4) The solid is a poor conductor, and the liquid is a good conductor.
Then the answer is number 4. This is because ionic compound conducts electricity when it is dissolved in water.
