What are the names of the two magnetic poles?
Ur answer is
North and South
Answer:
1.58x10⁻⁵
2.51x10⁻⁸
0.0126
63.10
Explanation:
Phenolphthalein acts like a weak acid, so in aqueous solution, it has an acid form HIn, and the conjugate base In-, and the pH of it can be calculated by the Handerson-Halsebach equation:
pH = pKa + log[In-]/[HIn]
pKa = -logKa, and Ka is the equilibrium constant of the dissociation of the acid. [X] is the concentrantion of X. Thus,
i) pH = 4.9
4.9 = 9.7 + log[In-]/[HIn]
log[In-]/[HIn] = - 4.8
[In-]/[HIn] = 
[In-]/[HIn] = 1.58x10⁻⁵
ii) pH = 2.1
2.1 = 9.7 + log[In-]/[HIn]
log[In-]/[HIn] = -7.6
[In-]/[HIn] = 
[In-]/[HIn] = 2.51x10⁻⁸
iii) pH = 7.8
7.8 = 9.7 + log[In-]/[HIn]
log[In-]/[HIn] = -1.9
[In-]/[HIn] = 
[In-]/[HIn] = 0.0126
iv) pH = 11.5
11.5 = 9.7 + log[In-]/[HIn]
log[In-]/[HIn] = 1.8
[In-]/[HIn] = 
[In-]/[HIn] = 63.10
The answer is Independent Variable
Answer:
B. Intermolecular forces are hard to overcome
Explanation:
A high boiling point indicates greater inter molecular forces between the molecules of the substance. Inter molecular forces is the force of attraction between the molecules of the substance, which has to be overcome or broken before the substance boils. Example, when water boils, the water molecule (H₂O) will be broken into hydrogen molecule and oxygen molecule.
Therefore, a high boiling point temperature indicates that intermolecular forces of the substance are hard to overcome.
B. Intermolecular forces are hard to overcome
23.01 g of zinc (Zn)
Explanation:
We have the following chemical reaction:
3 Zn + 2 H₃PO₄ = 3 H₂ + Zn₃(PO₄)₂
number of moles = mass / molar weight
number of moles of phosphoric acid = 23.1 / 98 = 0.236 moles
Taking in account the chemical reaction, we devise the following reasoning:
if 2 moles of H₃PO₄ are reacting with 3 moles of Zn
then 0.236 moles of H₃PO₄ are reacting with X moles of Zn
X = (0.236 × 3) / 2 = 0.354 moles of Zn
mass = number of moles × molar weight
mass of Zn = 0.354 × 65 = 23.01 g
Learn more about:
number of moles
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