Answer:
The answer to the question is
50 % of the original amount of potassium 40 will be left after one half life or 1.25 billion years
Explanation:
To solve the question we note that the half life is the time for half of the quantity of substance that undergoes radioactive decay to disintegrate, thus
we have
half life of potassium 40 K₄₀ = 1.25 billion years
To support the believe tht the rock was formed 1.25 billion years ago we have

After 1.25 billion years we have
=
=0.5 of
will be left or 50 % of the original amount of potassium 40 will be left
Answer:
The rough pavement acted as an unbalanced force that was able to stop the skateboard.
Explanation:
Answer: The molarity of each of the given solutions is:
(a) 1.38 M
(b) 0.94 M
(c) 1.182 M
Explanation:
Molarity is the number of moles of a substance present in liter of a solution.
And, moles is the mass of a substance divided by its molar mass.
(a) Moles of ethanol (molar mass = 46 g/mol) is as follows.

Now, molarity of ethanol solution is as follows.

(b) Moles of sucrose (molar mass = 342.3 g/mol) is as follows.

Now, molarity of sucrose solution is as follows.

(c) Moles of sodium chloride (molar mass = 58.44 g/mol) are as follows.

Now, molarity of sodium chloride solution is as follows.

Thus, we can conclude that the molarity of each of the given solutions is:
(a) 1.38 M
(b) 0.94 M
(c) 1.182 M
Answer:
go with the fourth one because I did that one