How many valence electrons are in an atom of gold?

Are there any molecules that form a square?

djyliett [7]

Yes there are. Perhaps the most famous and obvious is squaric acid.
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7 0

3 years ago

What is the molar mass of an unknown gas with a density of 2.00 g/L at 1.00 atm and 25.0 °C?

soldier1979 [14.2K]

Answer:

Explanation:Explanation:

Your starting point here will be the ideal gas law equation

∣

¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

a

P

V

=

n

R

T

a

∣

−−−−−−−−−−−−−−−

, where

P

- the pressure of the gas

V

- the volume it occupies

n

- the number of moles of gas

R

- the universal gas constant, usually given as

0.0821

atm

⋅

L

mol

⋅

K

T

- the absolute temperature of the gas

Now, you will have to manipulate this equation in order to find a relationship between the density of the gas,

ρ

, under those conditions for pressure and temperature, and its molar mass,

M

.

You know that the molar mass of a substance tells you the mass of exactly one mole of that substance. This means that for a given mass

m

of this gas, you can express its molar mass as the ratio between

m

and

n

, the number of moles it contains

∣

¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

a

M

=

m

n

a

∣

−−−−−−−−−−−−−

(

1

)

Similarly, the density of the substance tells you the mass of exactly one unit of volume of that substance.

This means that for the mass

m

of this gas, you can express its density as the ratio between

m

and the volume it occupies

∣

¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

a

ρ

=

m

V

a

∣

−−−−−−−−−−−

(

2

)

Plug equation

(

1

)

into the ideal gas law equation to get

P

V

=

m

M

⋅

R

T

Rearrange to get

P

V

⋅

M

=

m

⋅

R

T

P

⋅

M

=

m

V

⋅

R

T

M

=

m

V

⋅

R

T

P

Finally, use equation

(

2

)

to write

M

=

ρ

⋅

R

T

P

Convert the temperature of the gas from degrees Celsius to Kelvin then plug in your values to find

M

=

1.02

g

L

⋅

0.0821

atm

⋅

L

mol

⋅

K

⋅

(

273.15

+

37

)

K

0.990

atm

M

=

∣

¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

a

26.3 g mol

−

1

a

∣

−−−−−−−−−−−−−−−−

I'll leave the answer rounded to three

7 0

3 years ago

How many moles of oxygen will occupy a volume of 2.50 liters?

loris [4]

Data:
n (number of mols) = ?
V (volume) = 2.50 Liters
If:
1 L → 1000 g
2.50 L → y

y = 1000*2.50 = 2500 g

Therefore:
m (mass) = 2500 g

Now:
Molar Mass (MM) of oxygen = 16 g/mol

Formula:
$n = \frac{m}{MM}$

Solving:
$n = \frac{m}{MM}$
$n = \frac{2500\:\diagup\!\!\!\!\!g}{16\:\diagup\!\!\!\!\!g/mol}$
$\boxed{\boxed{n = 156.25\:mols}}\end{array}}\qquad\quad\checkmark$

7 0

2 years ago

Element X has the following valence electron configuration: [core]ns2np5. Element M has the following valence electron configura

alex41 [277]

Answer:

The kind of ionic compound formed is MX2.

Explanation:

Element X electron configuration is represented as [core] ns2np5. The group in the periodic table this element belong to is group 7A. The element group is called the halogen family. Element X cannot be stated specifically, because the number is represented with n. Element X will behave as an anions when it react with a metal(cations). Element X has a charge of -1. The element X will gain electron when it bond with a metal. Element X is a non metal . Elements in this group are fluorine, chlorine, bromine, iodine , astatine, and tennessine . The element X have 7 valency electrons.

Element M electronic configuration is represented as [core]ns2. The group in the periodic table this element belong to is group 2A . The element group is called the alkaline earth metals family . Element M will behave as a cation when it bond with a non metal. Element M is a metal , therefore it will likely lose electron to form cations during bonding . The charge of element M is 2+. Element M is positively charged. Elements that belong to this group includes beryllium, magnesium, calcium, strontium, barium and radium. Element M has 2 valency electrons.

The reaction between this 2 ions will likely form an ionic compound . The element M is the cations while the element X is the anions. The element M will lose 2 electron while 2 atoms of element X will gain 2 electrons.Element M will lose 2 electron to attain a stable configuration while 2 atoms of element X will gain a single electron each to attain a stable configuration.

M²+ and F- . This will form MX2 when you cross multiply the charge. The kind of ionic compound formed is MX2.

6 0

3 years ago

A student ran the following reaction in the laboratory at 671 K: 2NH3(g) N2(g) + 3H2(g) When she introduced 7.33×10-2 moles of N

vaieri [72.5K]

Answer:

Kc = 8.05x10⁻³

Explanation:

This is the equilibrium:

2NH₃(g) ⇄ N₂(g) + 3H₂(g)

Initially 0.0733

React 0.0733α α/2 3/2α

Eq 0.0733 - 0.0733α α/2 0.103

We introduced 0.0733 moles of ammonia, initially. So in the reaction "α" amount react, as the ratio is 2:1, and 2:3, we can know the moles that formed products.

Now we were told that in equilibrum we have a [H₂] of 0.103, so this data can help us to calculate α.

3/2α = 0.103

α = 0.103 . 2/3 ⇒ 0.0686

So, concentration in equilibrium are

NH₃ = 0.0733 - 0.0733 . 0.0686 = 0.0682

N₂ = 0.0686/2 = 0.0343

So this moles, are in a volume of 1L, so they are molar concentrations.

Let's make Kc expression:

Kc= [N₂] . [H₂]³ / [NH₃]²

Kc = 0.0343 . 0.103³ / 0.0682² = 8.05x10⁻³

3 0

3 years ago