Answer:
Near the boiling point of the solvent
Explanation:
The process of recrystallization is hinged on the fact that the amount of solute that can be dissolved by a solvent increases with temperature. The process involves creation of a solution by dissolving a solute in a solvent at or near its boiling point. At the boiling point of the solvent, the solute has a greater solubility in the solvent; not much volume of the hot solvent is required to dissolve the solute.
Before the solution is later cooled, you can now filter out insoluble impurities from the hot solvent. The quantity of the original solute drops appreciably because impurities have been removed. At this lower temperature, the solution becomes saturated and the solute can no longer be held in solution hence it forms pure crystals of solute, which can be recovered.
Recrystallization must be carried out using the proper solvent. The solute must be relatively insoluble in the solvent at room temperature but more soluble in the solvent at elevated temperature.
Answer: In Arizona, climate change is already making deadly heat waves, droughts and wildfires across the state worse. These impacts have real costs on Arizonans' health and economy, including heat-related deaths, higher electricity bills, crop losses and more.
Explanation:
https://www.edf.org/climate/costofinaction- this is where I gathered this info. Not mine. But I hope it helps!
Answer:
The molar mass of the unknown gas is 
Explanation:
Let assume that the gas is O2 gas
O2 gas is to effuse through a porous barrier in time t₁ = 4.98 minutes.
Under the same conditions;
the same number of moles of an unknown gas requires time t₂ = 6.34 minutes to effuse through the same barrier.
From Graham's Law of Diffusion;
Graham's Law of Diffusion states that, at a constant temperature and pressure; the rate of diffusion of a gas is inversely proportional to the square root of its density.
i.e
where K = constant
If we compare the rate o diffusion of two gases;
Since the density of a gas d is proportional to its relative molecular mass M. Then;
Rate is the reciprocal of time ; i.e
Thus; replacing the value of R into the above previous equation;we have:
We can equally say:
Hello!
A buffer is composed of a weak acid and its conjugate base or a weak base and its conjugate acid. From the given list:
HCl and HF: Strong Acid and Weak Acid. NOT BUFFER
HF and NaF: Weak Acid and Conjugate Base. BUFFER
HC₂H₃O₂ and KC₂H₃O₂: Weak Acid and Conjugate Base. BUFFER
NaOH and NH₃: Strong Base and Weak Base. NOT BUFFER.
Have a nice day!
