Answer:
2.57 e-9
Explanation:
The formula is H3O=10^-Ph
10^-8.59=2.57 e-9
Answer:
pKa = 3.675
Explanation:
∴ <em>C</em> X-281 = 0.079 M
∴ pH = 2.40
let X-281 a weak acid ( HA ):
∴ HA ↔ H+ + A-
⇒ Ka = [H+] * [A-] / [HA]
mass balance:
⇒<em> C</em> HA = 0.079 M = [HA] + [A-]
⇒ [HA] = 0.079 - [A-]
charge balance:
⇒ [H+] = [A-] + [OH-]... [OH-] is negligible; it comes from to water
⇒ [H+] = [A-]
∴ pH = - log [H+] = 2.40
⇒ [H+] = 3.981 E-3 M
replacing in Ka:
⇒ Ka = [H+]² / ( 0.079 - [H+] )
⇒ Ka = ( 3.981 E-3 )² / ( 0.079 - 3.981 E-3 )
⇒ Ka = 2.113 E-4
⇒ pKa = - Log ( 2.113 E-4 )
⇒ pKa = 3.675
Mole<span>: the amount of a substance that contains 6.02 x </span>10<span>. 23 respective particles of that substance. Avogadro's number: 6.02 x </span>10<span>. 23. Molar Mass: the mass of one </span>mole<span> of an element. CONVERSION FACTORS: 1 </span>mole<span> = 6.02 x </span>10<span>. 23 </span>atoms<span> 1 </span>mole<span> = </span>atomic<span> mass (g). Try: 1. How </span>many atoms<span> are in 6.5</span>moles<span> of zinc</span>
Answer: The pressure will be 18.05 atm.
Explanation: Expression for ideal gas equation is :
where,
P = Pressure of the gas = ? atm
V = Volume of the gas = 0.333L
n = Number of moles of gas = 0.250 moles
R = Universal gas constant = 
T = temperature of the gas = 20°C = (273 + 20)K = 293K
Putting values in above equation, we get:
P = 18.05 atm
Answer:
The number of valence electrons in an atom is reflected by its position in the periodic table of the elements (see the periodic table in the Figure below). Across each row, or period, of the periodic table, the number of valence electrons in groups 1–2 and 13–18 increases by one from one element to the next
