Which statement is NOT true about an Astronomical Unit?

The molar concentration (M) of a solution prepared by dissolving 0.2362g of Cr(NO3)3 in a 50-mL volumetric flask is 0.01985M, wh

Vinil7 [7]

Answer:

Here's what I get

Explanation:

You want to dilute the original solution by a factor of 25 in two steps, so you could dilute it by a factor of 5 in the first step, then dilute the new solution by another factor of 5.

A. First dilution

Use a 10 mL pipet to transfer 10 mL of the original solution to a 50 mL volumetric flask. Make up to the mark with distilled water. Shake well to mix.

Use the dilution formula to calculate the new concentration.

$\begin{array}{rcl}c_{1}V_{1} & = & c_{2}V_{2}\\0.01985 \times 10.00 & = & c_{2} \times 50.00\\0.1985 & = & 50.00 c_{2}\\\\c_{2}& = & \dfrac{0.1985}{50.00}\\\\& = & \text{0.003 970 mol/L}\\\end{array}$

B. Second dilution

Repeat Step 1, using the 0.003 970 mol·L⁻¹ solution.

$\begin{array}{rcl}c_{2}V_{2} & = & c_{3}V_{3}\\0.003970 \times 10.00 & = & c_{3} \times 50.00\\0.03970 & = & 50.00 c_{3}\\\\c_{3}& = & \dfrac{0.03970}{50.00}\\\\& = & \textbf{0.000 7940 mol/L}\\\end{array}\\\text{The concentration of the final solution is $\boxed{\textbf{0.000 7940 mol/L}}$}$

3. Check:

Compare the final concentration with the original

$\begin{array}{rcl}\dfrac{ c_{3}}{ c_{1}} & = & \dfrac{0.0007940}{0.01985}\\& = & \mathbf{\dfrac{1}{25.00}}\\\end{array}\\\text{The concentration of the final solution is } \boxed{\mathbf{\dfrac{1}{25}}} \text{ that of the original solution}$

7 0

3 years ago

Which alignment of the Sun, Moon, and Earth causes a lunar eclipse? А. B. C. D.

alukav5142 [94]

Answer:

A.

Explanation:

I'm awesome

7 0

3 years ago

Consider the unbalanced equation for the oxidation of butene. C4H8 + 6O2 Right arrow. CO2 + H2O For each molecule of C4H8 that r

antiseptic1488 [7]

Answer is C4H8 + 6O2 —> 4CO2 + 4H2O

4 0

3 years ago

Deforestation typically

MakcuM [25]

<span>Deforestation typically leads to soil erosion and the ruin of the ecosystem where deforestation occurred. The land gets destroyed and with it the natural habitat of the animals and plants who live there. In addition, we, the humans, lose oxygen because of lack of trees.</span>

4 0

4 years ago

At 24°C, Kp = 0.080 for the equilibrium: NH4HS (s) NH3 (g) + H2S (g) A sample of solid NH4HS is placed in a closed vessel and al

miss Akunina [59]

Answer:

Partial pressure of ammonia is 0,28.

Explanation:

For the reaction:

NH₄HS(s) ⇄ NH₃(g) + H₂S(g)

kp = 0,080 is defined as:

0,080 = P[NH₃] P[H₂S] <em>(1)</em>

Where P[NH₃] is partial pressure of NH₃

Asuming amount of NH₄HS is 1, equilibrium concentration for each compound is:

[NH₄HS] = 1 - x

P [NH₃] = x

P [H₂S] = x

Replacing in (1):

0,080 = X×X

0,080 = X²

X = 0,28 = P[NH₃]

I hope it helps

7 0

3 years ago