1A: The legs can be a adjusted, as well as the sand can be swapped out. It’s a very good design for running multiple tests.
1B: He could add books or something under the front or back legs in order to increase/decrease the incline, therefore imitating the hypothesis.
1C: He can change out the sand grains to finer ones, or coarser ones, and record his results of each test.
2: If he sets the model at a steep incline and tests it with coarse sand and fine sand, seeing which one makes a narrower, deeper hole.
Chemical reactions are a change in substance while nuclear is destruction
Answer:
Use pOH = -log₁₀ [OH-]
Explanation:
pOH can be calculated from the concentration of hydroxide ions using the formular below:
pOH = -log₁₀ [OH-]
The pOH is the negative logarithm of the hydroxide ion concentration.
Answer: The molar mass of the gas is 9.878 g/mol.
Explanation:
According to Graham's law, the rate of diffusion is inversely proportional to square root of molar mass of gas.
where,
M = molar mass of gas
As given gas diffuses 1/7 times faster than hydrogen gas. So, its molar mass is calculated as follows.
where,
= molar mass of hydrogen gas
= molar mass of another given gas
= rate of diffusion of hydrogen
= rate of diffusion of another given gas = 
Substitute the values into above formula as follows.
Thus, we can conclude that the molar mass of the gas is 9.878 g/mol.
