Answer: a,b
Explanation: because a scientific theory is something that been thought of and tested multiple times.
Probably, above 100 Degree Celsius.
Answer:
Physical Change
Explanation:
The bush is changing shapes, not changing what it is.
Answer is: Ksp for calcium sulfate is 2.36·10⁻⁴.
Balanced chemical reaction (dissociation):
CaSO₄(s) → Ba²⁺(aq) + SO₄²⁻(aq).
m(CaSO₄) = 0.209 g.
n(CaSO₄) = m(CaSO₄) ÷ M(CaSO₄).
n(CaSO₄) = 0.209 g ÷ 136.14 g/mol.
n(CaSO₄) = 0.00153 mol.
s(CaSO₄) = n(CaSO₄) ÷ V(CaSO₄).
s(CaSO₄) = 0.00153 mol ÷ 0.1 L = 0.0153 M.
Ksp = [Ca²⁺] · [SO₄²⁻].
[Ca²⁺] = [SO₄²⁻] = s(CaSO₄).
Ksp = (0.0153 M)² = 2.36·10⁻⁴.
Answer:
kb = 2,0x10⁻⁵
Explanation:
The ka for HCN is:
HCN ⇄ H⁺ + CN⁻; ka = 4,9x10⁻¹⁰ <em>(1)</em>
The inverse reaction has an equilibrium constant of:
H⁺ + CN⁻ ⇄ HCN k = 1/4,9x10⁻¹⁰ = 2,0x10⁹ <em>(2)</em>
As the equilibrium of the water is:
H₂O ⇄ H⁺ + OH⁻; kw = 1x10⁻¹⁴ <em>(3)</em>
The sum of (2) + (3) gives:
H₂O + CN⁻ ⇄ HCN + OH⁻; kb = kw×k = 1x10⁻¹⁴×2,0x10⁹ =
2,0x10⁻⁶; <em>kb = 2,0x10⁻⁵</em>
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<em>-In fact, the general formula to convert from ka to kb is:</em>
<em>kb = kw / ka-</em>
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I hope it helps!
