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2 years ago

HELP ASAP!!!

Chemistry

2 answers:

forsale [732]2 years ago

8 0

Answer:

Explanation:

1 mole = 6.022×1023 6.022 × 10 23 atoms, molecules, protons, etc. To convert from moles to atoms, multiply the molar amount by Avogadro's number. To convert from atoms to moles, divide the atom amount by Avogadro's number (or multiply by its reciprocal).

neonofarm [45]2 years ago

3 0

Answer:

Explanation:

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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

If you have 250 mL of 0.75 M LINO2.<br> How many grams of this substance<br> would you have?

Vesna [10]

Mass of this substance = 9.928 g

<h3>Further explanation</h3>

Molarity is a way to express the concentration of the solution

Molarity shows the number of moles of solute in every 1 liter of solute or mmol in each ml of solution

$\large{\boxed {\bold {M ~ = ~ \frac {n} {V}}}$

Where

M = Molarity

n = Number of moles of solute

V = Volume of solution

So to find the number of moles can be expressed as

$\boxed{\bold{n=V\times M}}$

mol of substance -Lithium nitrite - LiNO₂ :

V = 250 ml = 0.25 L

M = 0.75 M

$\tt n=0.25\times 0.75=0.1875$

So mass of this substance - LiNO₂ (MW=52,947 g/mol) :

$\tt mass=mol\times MW\\\\mass=0.1875\times 52,947 g/mol\\\\mass=9.928~g$

4 0

2 years ago

Helpppppppp plzzzzzz asaaaapppp

9966 [12]

Answer:

Alright, the first thing we have to do is to balance the chemical equation

2Na3N -----> 6Na + 1N2

We have 60g of Na3N, we convert them into moles by dividing the mass of the compound by the molar mass.

Molar mass of Na3N = (22.98 x 3) + (14) = 82.94g/mol

<u>60</u> = 0.72341451651 moles of Na3N

82.94

Now because we did the balanced equation, we know the mole to mole ratio of Na3N to N2 would be 2:1, so in order to get the moles of N2 you have to divide the moles of Na3N by 2

0.72341451651 moles/2 = 0.361707258 moles of N2

Now that we have the moles of N2, we just have to determine the mass of it in grams. In order to do that, just multiply the moles by the molar mass of N2 (28g/mol)

0.361707258 x 28 = <u>10.13g of N2</u>

<u>Therefore the decomposition of 60g of Na3N would result in 10.13g of N2 (nitrogen gas)</u>

3 0

2 years ago

What is the concentration of H+ ions at a pH = 2?

kari74 [83]

<h2><u>PLEASE MARK BRAINLIEST!</u></h2>

In Step 5, you will calculate H+/OH– ratios for more extreme pH solutions. Find the concentration of H+ ions to OH– ions listed in Table B of your Student Guide for a solution at a pH = 2. Then divide the H+ concentration by the OH– concentration. Record these concentrations and ratio in Table C.

What is the concentration of H+ ions at a pH = 2?

What is the concentration of OH– ions at a pH = 2?

What is the ratio of H+ ions to OH– ions at a pH = 2?

Those are your correct answers on edg2020!

I LITERALLY spent 40 MINUTES trying to figure out this question, so please, use my VERY CORRECT answers!

<em>I hope this helps!</em>

6 0

2 years ago

250 mL of water is collected during a combustion reaction. The temperature in the

klio [65]

Answer:

10.67 moles is the answers.hope it helped

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2 years ago