Answer:

Explanation:
Let x be the distance to the shore
From trigonometry properties:

<span>Avogadro's number
represents the number of units in one mole of any substance. This has the value
of 6.022 x 10^23 units / mole. This number can be used to convert the number of
atoms or molecules into number of moles.
</span>2.39 moles Ne ( 6.022 x 10^23 atoms / mole ) = 1.44 × 10^24 atoms Ne
As the density of the unknown substance is 0.68g/0.8ml = 0.85g/ml, it is less dense than the maple syrup at 1.33g/ml and will float.
Answer:
We know that the speed of sound is 343 m/s in air
we are also given the distance of the boat from the shore
From the provided data, we can easily find the time taken by the sound to reach the shore using the second equation of motion
s = ut + 1/2 at²
since the acceleration of sound is 0:
s = ut + 1/2 (0)t²
s = ut <em>(here, u is the speed of sound , s is the distance travelled and t is the time taken)</em>
Replacing the variables in the equation with the values we know
1200 = 343 * t
t = 1200 / 343
t = 3.5 seconds (approx)
Therefore, the sound of the gun will be heard at the shore, 3.5 seconds after being fired