Answer:
Yttrium barium copper oxide (YBCO) is a family of crystalline chemical compounds, famous for displaying high-temperature superconductivity.It includes the first material ever discovered to become superconducting above the boiling point of liquid nitrogen (77 K) at about 92 K.Many YBCO compounds have the general formula Y Ba 2 Cu 3 O 7−x (also known as Y123),
Explanation:
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Answer:
Below
Explanation:
Balanced equation: 2NaOH + (NH4)2SO4 = 2NH3 + 2H2O + Na2SO4
The coefficients would be 2
Nitrous acid<span> dissociates as follows:
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HNO₂(s) ⇄ H⁺(aq) + NO₂⁻(aq)
According to the equation, an acid constant has the following form:
Ka = [H⁺] × [NO₂⁻ ] / [HNO₂]
From pH, we can calculate the concentration of H⁺ and NO₂⁻:
[H⁺] = 10^-pH = 10^-2.63 = 0.00234 M = [NO₂⁻]
Now, the acid constant can be calculated:
Ka = 0.00234 x 0.00234 / 0.015 = 3.66 x 10⁻⁴
And finally,
pKa = -log Ka = 3.44
A compound is a substance made up of atoms of two or more different elements joined by chemical bonds. A mixture is a combination of two or more substances that are not chemically combined.
