Answer:
The answer to your question is 14.3 %
Explanation:
Data
volume of ethanol = 50 ml
volume of water = 300 ml
volume percent = ?
Formula
Percent by volume = (volume of solute/volume of solution) x 100
Volume of solute = 50 ml
volume of solution = 300 + 50 = 350
Substitution
Percent by volume = (50/350) x 100
Simplification and result
Percent by volume = 14.3 %
Explanation:
Answer:
The pH of a solution containing an amphetamine (with pKb of 4.2) concentration of 250 mg/l is 10.5
Explanation:
To solve the question we note that the
The mass of amphetamine = 250 mg/l
The molar mass of amphetamine = 135.2062 g/mol
Number of moles of amphetamine = (250 mg)/(135.2062 g/mol) = 1.85×10⁻³ moles
That is the initial concentration of amphetamine = 1.85×10⁻³ M
We have
therefore
Which gives 6.3×10⁻⁵
x = 0.0003116 = [OH⁻] = [C₉H₁₃NH⁺]
However x = [OH⁻] = 3.116×10⁻⁴
pOH = -log[OH⁻] = -log(3.116×10⁻⁴) = 3.506
pH = 14 - pOH
= 14 - 3.506
= 10.49
≈ 10.5
This energy required is the latent heat, which is required for physical transformations. Specifically, when it involves changing liquid to gas, this latent heat is called the heat of vaporization. The formula is:
Q = mΔHvap
The molar mass of the compound is
Q = (48.7 g)(31.6 kJ/mol)(1 mol/84.93 g)
<em>Q = 18.12 kJ</em>
The total charge of a compound must be zero. So the Y ion has charge of -2. Then the charge of X ion+(-2)*2=0. So the charge of X ion is +4.