Answer:
[NO₂] = 0.434 M
[N₂O₄] = 0.0971 M
Explanation:
The equilibrum is: N₂O₄(g) ⇆ 2NO₂ (g)
1 moles of nitrogen (IV) oxide is in equilibrium with 2 moles of nitrogen dioxide.
Initally we only have 2.20 moles of NO₂. So let's write the equilibrium again:
2NO₂ (g) ⇆ N₂O₄(g)
Initially 2.20 mol -
React x x/2
X amount has reacted, and the half has been formed, according to stoichiometry.
Eq (2.20-x) / 3.50L (x/2)/ 3.50L
We divide by the volume because we need molar concentrations. Let's make the Kc's expression:
Kc = [N₂O₄] / [NO₂]²
0.513 = ((x/2)/ 3.50L) / [(2.20-x) / 3.50L]
0.513 = ((x/2)/ 3.50L) / [(2.20-x)² / 3.50L²]
0.513 = ((x/2)/ 3.50L) / [2.20-x)² / 3.50L²]
0.513 = ((x/2)/ 3.50L) / (4.84 - 4.40x + x²) / 12.25)
0.513 / 12.25 (4.84 - 4.40x + x²) = x/2 / 3.50
0.203 - 0.184x + 0.0419x² = x/2 / 3.50
3.50(0.203 - 0.184x + 0.0419x²) = x/2
7 (0.203 - 0.184x + 0.0419x²) - x = 0
1.421 - 2.288x + 0.2933x² = 0 → Quadratic formula
a = 0.2933 ; b = -2.288 ; c = 1.421
(-b +- √(b²-4ac)) / (2a)
x₁ = 7.12
x₂ = 0.68 → We consider this value, so we can have a (+) concentration.
Concentrations in the equilibrium are:
[NO₂] = (2.20-0.68) / 3.50 = 0.434 M
[N₂O₄] = (0.68/2) / 3.50 = 0.0971 M
Answer:
One: <u>Selenium</u> is Paramagnetic
Explanation:
Those compounds which have unpaired electrons are attracted towards magnet. This property is called as paramagnetism. Lets see why remaining are not paramagnetic.
Electronic configuration of Scandium;
Sc = 21 = 1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹
Sc³⁺ = 1s², 2s², 2p⁶, 3s², 3p⁶
Hence in Sc³⁺ there is no unpaired electron.
Electronic configuration of Bromine;
Br = 35 = 1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁵
Br⁻ = 1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁶
Hence in Br⁻ there is no unpaired electron.
Electronic configuration of Magnesium;
Mg = 12 = 1s², 2s², 2p⁶, 3s²
Mg²⁺ = 1s², 2s², 2p⁶
Hence in Mg²⁺ there is no unpaired electron.
Electronic configuration of selenium;
Se = 34 = 1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁴
Or,
Se = 34 = 1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4px², 4py¹, 4pz¹
Hence in Se there are two unpaired electrons hence it is paramagnetic in nature.
Answer:
A chemical reaction in which an uncombined element replaces an element that is part of a compound is called a simple substitution reaction or simple displacement reaction.
Explanation:
A simple substitution reaction or simple displacement reaction, called single-displacement reaction, is a reaction in which an element of a compound is substituted by another element involved in the reaction. The starting materials are always pure elements and an aqueous compound. And a new pure aqueous compound and a different pure element are generated as products. The general form of a simple substitution reaction is:
AB + C → A +BC
where C and A are pure elements; C replaces A within compound AB to form a new co, placed CB and elementary A.
So, in a Single replacement reaction an uncombined element replaces an element.
<u><em>A chemical reaction in which an uncombined element replaces an element that is part of a compound is called a simple substitution reaction or simple displacement reaction.</em></u>
Zinc is a metal. At STP, it exists as solid and is stable as it is. It is an important mineral and is used in many applications like in food, metal and drugs. Zinc can be found in the Earth's crust and also it is present in small amounts in some food.
Electrons determine the chemical properties. Protons and neutrons are in the nucleus the number of protons determines the number of electrons of an atom
