Answer: Option (A) is the correct answer.
Explanation:
Rate of diffusion is defined as the total movement of molecules from a region of higher concentration to lower concentration.
The interaction between medium and the material is responsible for the rate of diffusion of a material or substance.
A small concentration gradient means small difference in the number of molecules taking part in a reaction. So, when there no large difference between the concentration then there won't be much difference in the rate of diffusion of a material.
Whereas a higher concentration of molecules will lead to more number of collisions due to which frequency of molecules increases. Therefore, rate of diffusion will also increase.
Small molecule size will also lead to increases in rate of diffusion. This is because according to Graham's law rate of diffusion is inversely proportional to molar mass of an element. Hence, smaller size molecule will have smaller mass. As a result, rate of diffusion will be more.
High temperature means more kinetic energy of molecules due to which more number of collisions will be there. Hence, rate of diffusion will also increase.
Thus, we can conclude that out of the given options a small concentration gradient is least likely to increase the rate of diffusion.
There are TWO atoms in one molecule of hydrogen.
Answer:

Explanation:
Hello there!
In this case, according to the given information, it turns out firstly necessary for us to set the equation for the calculation of density and mass divided by volume:

Thus, we can find the mass of the unknown by subtracting the total mass of the liquid to the mass of the flask and the liquid:

So that we are now able to calculate the density in g/mL first:

Now, we proceed to the conversion to lb/in³ by using the following setup:

Regards!
Answer:
9.28
Explanation:
pOH refers to a measure of hydroxide ions concentration. pOH tells about the alkalinity of a solution. If pOH is less than 7 then aqueous solutions are alkaline, acidic if pOH is greater than 7 and neutral if pOH is equal to 7.
Concentration of the hydroxide ions = 1.9 x 10-5 M
pH = 
pOH = 14 - pH
=14 - 4.72 = 9.28