67.45 is the answer I think
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:






Answer:
Here's how I would explain it.
Explanation:
Think of it this way.
When you mix solutions of silver nitrate and sodium chloride, you get an immediate precipitate of silver chloride. The equation is
Ag⁺(aq) + Cl⁻(aq) ⟶ AgCl(s)
Now, take some AgCl and stir it vigorously with water.
You won't see much happening, because the AgCl is has such a low solubility. Not much of it will go into solution. And yet, a small amount of it does dissolve until the solution is saturated.
The concentration of AgCl in the saturated solution is
about 0.000 01 mol·L⁻¹.
I hope you will agree that this is a dilute solution even though it is saturated with AgCl.
I'm not able to understand that what is written in the pic.. As I can't understand this language..
Treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. Chemotherapy may be given by mouth, injection, or infusion, or on the skin, depending on the type and stage of the cancer being treated.