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3 years ago

Calculate the number of moles of potassium permanganate (KMnO4) corresponding to 230.8 g of the substance.

Chemistry

1 answer:

vlada-n [284]3 years ago

6 0

Answer:

The answer to your question is 1.46 moles of KMnO₄

Explanation:

Data

number of moles = ?

mass = 230.8 g

molecular mass of KMnO₄ = 39 + 55 + (16 x 4) = 158 g

Process

1.- Use proportions and cross multiplication to answer this problem.

158 g of KMnO₄ ---------------- 1 mol

230.8 g of KMnO₄ ----------- x

x = (230.8 x 1) / 158

2.- Simplifying

x = 230.8 / 158

3.- Result

x = 1.46 moles

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The half-life of nitrogen-13 is 10.0 minutes. if you begin with 53.3 mg of this isotope, what mass remains after 25.9 minutes ha

zimovet [89]

Hello!

The half-life is the time of half-disintegration, it is the time in which half of the atoms of an isotope disintegrate.

We have the following data:

mo (initial mass) = 53.3 mg

m (final mass after time T) = ? (in mg)

x (number of periods elapsed) = ?

P (Half-life) = 10.0 minutes

T (Elapsed time for sample reduction) = 25.9 minutes

Let's find the number of periods elapsed (x), let us see:

$T = x*P$

$25.9 = x*10.0$

$25.9 = 10.0\:x$

$10.0\:x = 25.9$

$x = \dfrac{25.9}{10.0}$

$\boxed{x = 2.59}$

Now, let's find the final mass (m) of this isotope after the elapsed time, let's see:

$m = \dfrac{m_o}{2^x}$

$m = \dfrac{53.3}{2^{2.59}}$

$m \approx \dfrac{53.3}{6.021}$

$\boxed{\boxed{m \approx 8.85\:mg}}\end{array}}\qquad\checkmark$

I Hope this helps, greetings ... DexteR! =)

3 0

2 years ago

During which intervals is potential energy decreasing and average kinetic energy remaining constant?

Sholpan [36]

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