The general properties of matter result from its relationship with mass and space. ... Because it occupies space, all matter has volume and impenetrability, since two objects cannot occupy the same space simultaneously.
B. a large continent from long ago that eventually broke up into the continents we have today
Answer:
protons
Explanation:
An element, by definition, always has the same number of protons. Sodium, element 11, has 11 protons. Anything with 11 protons is a sodium atom, regardless of the number of neutrons, electrons, or politicians.
First we dissociate the salt
NaOCl ⇒ Na⁺ + OCl⁻
note that [NaOCl] = [OCl⁻]
note that Na⁺ does not undergo hydrolysis so it is a spectator.
OCl⁻ can reform HOCl in an equilibrium, with OCl⁻ acting as the base.
OCl⁻ + H₂O ⇄ OH⁻ + HOCL
<span>Ka for HOCl = 3.0x10^-8, therefore
Kb for OCL</span>⁻ = Kw / (Ka for HOCl)
= 1.0 × 10⁻¹⁴ / 3.0 <span>× 10⁻⁸
= 3.3 × 10⁻⁷
</span>since Kb for OCl⁻ is given, and the pH is given, then [OCl⁻] must be found, and [OCl⁻] = [NaOCl]
convert the pH into [OH⁻]:
pOH = 14 - pH = 14 - 10.3 = 3.7
[OH⁻] = 10^(-3.7) = 1.995 × 10⁻⁴
set up equib table
OCl⁻ + H₂O ⇄ OH⁻ + HOCl
ST x 0 0
+Δ -1.995 × 10⁻⁴ +1.995 × 10⁻⁴ +1.995 × 10⁻⁴
---------------------------------------------------------------------------------
EQ: x -1.995 × 10⁻⁴ 1.995 × 10⁻⁴ 1.995 × 10⁻⁴
Kb = [OH⁻][HOCl] / [OCl⁻]
3.3 × 10⁻⁷ = (1.995 × 10⁻⁴)² / (x -1.995 × 10⁻⁴ )
x = 1.1963 × 10⁻¹ M = [OCl⁻] = [NaOCl]
The concentration of the salt formed, <span>NaOCl,</span> is 1.2 × 10⁻¹ M
<span>Answer: 1.06 moles of molecules = 6.38x10²³ molecules
</span><span />
<span>Explanation:
</span><span />
<span>1) Balanced chemical equation:
</span><span />
<span>2Na + 2H₂O -> 2NaOH + H₂
</span><span />
<span>2) Mole ratios:
</span><span />
<span>2 mol Na : 2 mol H₂O : 2 mol NaOH : 1 mol H₂
</span><span />
<span>3) Convert 48.7 g of sodium to moles:
</span><span />
<span>number of moles = mass in grams / molar mass
</span><span />
<span>molar mass of Na = atomic mass = 23.0 g/mol
</span><span>number of moles = 48.7g / 23.0 g/mol = 2.12 moles of Na</span>
<span /><span>
4) Proportion:
</span><span />
<span>2moles Na/1mol H₂ = 2.12 moles Na / x
</span><span />
<span>x = 2.12 moles Na * 1 mol H₂ / 2 moles Na = 1.06 moles H₂.
</span><span />
<span>5) If you want to convert that to number of molecules you have to multiply by Avogadro's number: 6.022 x 10^²³
</span><span />
<span>1.06 mol x 6.022x10^²³ molecules/mol = 6.38x10²³ molecules</span>
