Evaporation technique is used to separate a compound dissolved in a solvent by vaporizing the solvent and converting it to gaseous state. This leaves behind the solid residue present in the solution after the pure solvent is vaporized. The solvent vapors can be collected and condensed to get pure solvent. But the solid residue cannot be considered pure as it is the left over solid after all the solvent is evaporated. If the solution has some impurities, the solid left over includes all of the impurities. So, we cannot obtain a pure solid in evaporation technique.
Answer:
V₂ = 568.9 mL
Explanation:
Given data:
Volume of gas = 550 mL
Pressure of a gas = 960 mmHg
Temperature = 200.0°C ( 200+273 = 473 K)
Final volume = ?
Final pressure = 830 mmHg
Final temperature = 150°C (150+273 = 423 K)
Solution:
Formula:
P₁V₁/T₁ = P₂V₂/T₂
P₁ = Initial pressure
V₁ = Initial volume
T₁ = Initial temperature
P₂ = Final pressure
V₂ = Final volume
T₂ = Final temperature
Solution:
V₂ = P₁V₁ T₂/ T₁ P₂
V₂ = 960 mmHg × 550 mL × 423 K / 473 K ×830 mmHg
V₂ = 223344000 mL / 392590
V₂ = 568.9 mL
Answer:
26.95 %
Explanation:
Air contains the highest percentage of oxygen and nitrogen gases. Magnesium then combines with both of the gases:
Firstly, find the total number of moles of magnesium metal:
Let's say that x mol react in the first reaction and y mol react in the second reaction. This means:
According to stoichiometry, we form:
Multiplying moles by the molar mass of each substance will yield mass. This means we form a total of:
The total mass is given, so we have our second equation to solve:
We have two unknowns and two equations, we may then solve:
Express y from the first equation:
Substitute into the second equation:
Moles of nitride formed:
Convert this to mass:
Find the percentage:
