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3 years ago

13

An element has an atomic number of 18 and an atomic mass of 40. The number of neutrons in the nucleus of an atom of this element

is????

1 answer:

Vikentia [17]3 years ago

7 0

Answer: 22 neutrons

Explanation: 40 is the mass number = atomic mass = total number of protons and neutrons in atomic nucleus

18 is the number of protons in the nucleus of this atom

Then 40 - 18 = 22 neutrons

and this is Argon

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If 30 ml of water containing 15 mg of salicylate is extracted with 30 ml of chloroform, 2.59 mg of salicylate remains in the wat

In-s [12.5K]

Answer:

Distribution coefficient: 4.79

Explanation:

Distribution coefficient is the ratio between equilibrium concentration of non-aqueous phase and aqueous phase where both solvents are inmiscible. The equation for the problem is:

Distribution coefficient: Concentration in chloroform / Concentration in Water

<em>Concentration in water: 2.59mg / 30mL = 0.08633mg/mL</em>

<em>Concentration in chloroform: (15mg-2.59mg) / 30mL = 0.4137mg/mL</em>

<em />

Distribution coefficient: 0.4137mg/mL / 0.08633mg/mL

<h3>Distribution coefficient: 4.79</h3>

8 0

3 years ago

What are a physical properties?

pychu [463]

Physical properties include: appearance, texture, color, boiling point, melting point, ect.

7 0

3 years ago

When a sodium atom becomes an ion the size of the atom?

jeyben [28]

The size of atom reduces

Electronic configuration of sodium -
2,8,1

In order to become stable it loses one electron and becomes positive ion.
It's size reduces.

3 0

3 years ago

If 24k gold is the highest purity (100%), then a 6 Karat piece of gold jewelry would contain what percentage of gold?

krok68 [10]

Answer:

25% gold.

Explanation:

6 is 25 percent of 24, so 6 karat gold would be 25% gold.

4 0

3 years ago

Given the two reactions H2S(aq)⇌HS−(aq)+H+(aq), K1 = 9.57×10−8, and HS−(aq)⇌S2−(aq)+H+(aq), K2 = 1.46×10−19, what is the equilib

Dvinal [7]

<u>Answer:</u> The value of $K_c$ for the final reaction is $7.16\times 10^{25}$

<u>Explanation:</u>

The given chemical equations follows:

<u>Equation 1:</u> $H_2S(aq.)\rightleftharpoons HS^-(aq.)+H^(aq.);K_1$

<u>Equation 2:</u> $HS^-(aq.)\rightleftharpoons S^{2-}(aq.)+H^(aq.);K_2$

The net equation follows:

$S^{2-}(aq.)+2H^+(aq.)\rightleftharpoons H_2S(aq.);K_c$

As, the net reaction is the result of the addition of reverse of first equation and the reverse of second equation. So, the equilibrium constant for the net reaction will be the multiplication of inverse of first equilibrium constant and the inverse of second equilibrium constant.

The value of equilibrium constant for net reaction is:

$K_c=\frac{1}{K_1}\times \frac{1}{K_2}$

We are given:

$K_1=9.57\times 10^{-8}$

$K_2=1.46\times 10^{-19}$

Putting values in above equation, we get:

$K_c=\frac{1}{(9.57\times 10^{-8})}\times \frac{1}{(1.46\times 10^{-19})}=7.16\times 10^{25}$

Hence, the value of $K_c$ for the final reaction is $7.16\times 10^{25}$

5 0

3 years ago