Answer:
Baking soda is an alkaline, or base, substance. This means that when we dissolve baking soda in water, it forms an alkaline solution. For example, a 0.1 molar solution of baking soda has a pH of around 8.3. Lemon juice contains citric acid and has a pH of around 3.
Answer:
Dissociated state is the predominant one
Explanation:
When a molecule with pKa of 4.52 is in an aqueous solution at pH = 4.0, follows the H-H equation, thus:
pH = pKa + log₁₀ [A⁻] / [HA]
<em>Where [A⁻] is the dissociated state and [HA] represents the protonated state</em>
Replacing:
4.0 = 5.2 + log₁₀ [A⁻] / [HA]
-1.2 = log₁₀ [A⁻] / [HA]
0.063 = [A⁻] / [HA]
[HA] = 16 [A⁻]
That means you have 16 times more [HA] than [A⁻] and the <em>dissociated state is the predominant one</em>
Answer: C
Explanation: This is because of a nice thing called guessing
Answer:
0.214 L
Explanation:
Step 1: Write the balanced equation
This is a single displacement reaction.
Zn(s) + 2 HCl(aq) ⇒ ZnCl₂(aq) + H₂(g)
Step 2: Calculate the moles corresponding to 0.625 g of Zn
The molar mass of Zn is 65.38 g/mol.
0.625 g × 1 mol/65.38 g = 9.56 × 10⁻³ mol
Step 3: Calculate the moles of H₂ produced from 9.56 × 10⁻³ moles of Zn
The molar ratio of Zn to H₂ is 1:1. The moles of H₂ produced are 1/1 × 9.56 × 10⁻³ mol = 9.56 × 10⁻³ mol.
Step 4: Calculate the volume occupied by 9.56 × 10⁻³ moles of hydrogen
Assuming standard pressure and temperature, 1 mole of hydrogen occupies 22.4 L.
9.56 × 10⁻³ mol × 22.4 L/1 mol = 0.214 L
Answer:
4 elements for C7H5(NO2)3
