Under the Doppler Effect, an observer behind a moving wave source observes
2 answers:
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Answer:
0.86 g/mL
Explanation:
In order to solve the problem, you have to know the formula for "Density." Density refers to<em> </em><em>"mass per unit volume." </em><em>It's formula is:</em>
- <em>Density (ρ) = </em>
<em />
Next, we have to convert the units of measurement in accordance to what is being asked in the problem. It is asking for "g/mL," which means we have to convert 1.25 quarts<em> (qt.) </em>to mL and 2.25 pounds<em> (lbs.)</em> to grams.
Let's solve.
- 1 quart = 946.35 mL
1.25 qt. x =<em> 1,182.94 mL</em>
- 1 pound = 453.592 grams
2.25 pounds x = <em>1,020.58 grams</em>
Now that we converted them to their appropriate units of measurement, we can now solve for density.
- <em>ρ = </em>
- <em>ρ = </em>
<em />
- <em>ρ = 0.86 g/mL</em>
<em>The density of the motor oil is 0.86 g/mL</em>
Explanation:
The given data is as follows.
Thickness = 0.28 mm = cm = 0.028 cm
Area = 0.40 =
= 4000
As, it is known that volume = area × thickness
So, Volume =
= 112
As density is mass divided by volume. So, mass of chromium will be calculated as follows.
Density =
7.20 =
mass = 806.4 g
As, mass of 1 mole of chromium is 52 g. So, number of moles in 806.4 g of chromium will be as follows.
No. of moles =
=
= 15.50 mol
In chromate ion, () charge on Cr is +6. It means that 6 electrons are needed to reduce
into Cr.
As, 1 mole of ions require 6 moles of electrons. Therefore, moles of electrons for 15.50 mol will be calculated as follows.
6 × 15.50 mol = 93.04 mol
To calculate number of electrons we multiply number of moles by Avogadro's number as follows.
=
= electrons
There is magnitude of times the charge on an electron is equal to 1 coulomb.
Hence, number of coulombs will be as follows.
No. of coulombs =
= C
or, = C
Thus, we can conclude that C are required to plate a layer of chromium metal with given data.