Answer:
Melting of ice
Explanation:
A physical change is one in which just the physical properties of the matter is altered. Most phase changes reaction falls under this type of change.
- Examples are boiling, melting, freezing, condensation, sublimation, magnetization of metals, breaking glass, cutting wood.
- No new kinds of matter is formed.
- The process is reversible
- No change in mass
Answer:
0.4M NaOH
Explanation:
Molarity, M, is an unit of concentration widely used defined as the ratio between moles of solute (In this case, NaOH) and volume of solution in liters.
As the solution contains 2 moles of NaOH-Moles of solute- in 5L of solution, the molarity is:
2 moles NaOH / 5L =
<h3>0.4M NaOH</h3>
Answer:
The pH of the solution is 7, 52
Explanation:
The pH gives us an idea of the acidity or alkalinity of a solution. Is calculated:
pH = -log (H +)
pH= -log ( 3x10-8)= <em>7, 52</em>
<span>'Do all liquids evaporate at the same rate
that would be false
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Answer:
pH = 6.8124
Explanation:
We know pH decreases with increase in temperature.
At room temperature i.e. 25⁰c pH of pure water is equal to 7
We know
Kw = [H⁺][OH⁻]...............(1)
where Kw = water dissociation constant
At equilibrium [H⁺] = [OH⁻]
So at 37⁰c i.e body temperature Kw = 2.4 × 10⁻¹⁴
From equation (1)
[H⁺]² = 2.4 × 10⁻¹⁴
[H⁺] = √2.4 × 10⁻¹⁴
[H⁺] = 1.54 × 10⁻⁷
pH = - log[H⁺]
= - log{1.54 × 10⁻⁷}
= 6.812
