Answer:
V CH3OH = 262.5 mL
Explanation:
- %v/v = (v compound / v sln)×100
∴ %v/v = 21.0 %
∴ v sln = 1.25 L
⇒ v compound = ?
⇒ 21.0 % = ( v compound / 1.25)×100
⇒ 0.21 = v compound / 1.25 L
⇒ (0.21)*(1.25 L) = v compound
⇒ v compound = 0.2625 L = 262.5 mL
Answer:
pH=4.63
Explanation:
The firt step is identify the <u>Acid</u> and the <u>conjugated base</u>:
HA <=> +
So, for this case we will have:
<=> +
Then:
HA =
=
With this in mind we can use the <u>henderson-hasselbach equation</u>:
pH = pKa + Log
We can calculate the <u><em>pKa</em></u> first
Then we can put the values in the equation:
pH = 4.2 + Log()
pH= 4.63
P = m/v
P = 0.297g/150.0ml
P = 1.98x10^-3 g/ml
Answer:
27.8 minutes
Explanation:
The reaction follows a first order
Rate = k[A] = change in concentration/time
k = 9×10^-3s^-1
Let the original concentration of A be y
Concentration of A at time t = 6.25% × y = 0.0625y
Change in concentration = y - 0.0625y = 0.9375y
0.009 × 0.0625y = 0.9375y/t
t = 0.9375y/0.0005625y = 1666.7sec = 1666.7/60 = 27.8 minutes