Answer:
(3) 5.36
Explanation:
Since this is a titration of a weak acid before reaching equivalence point, we will have effectively a buffer solution. Then we can use the Henderson-Hasselbalch equation to answer this question.
The reaction is:
HAc + NaOH ⇒ NaAc + H₂O
V NaOH = 40 mL x 1 L/1000 mL = 0.040 L
mol NaOH reacted with HAc = 0.040 L x 0.05 mol/L = 0.002 mol
mol HAC originally present = 0.050 L x 0.05 mol/L = 0.0025 mol
mol HAc left after reaction = 0.0025 - 0.002 = 0.0005
Now that we have calculated the quantities of the weak acid and its conjugate base in the buffer, we just plug the values into the equation
pH = pKa + log ((Ac⁻)/(HAc))
(Notice we do not have to calculate the molarities of Ac⁻ and HAc because the volumes cancel in the quotient)
pH = -log (1.75 x 10⁻⁵) + log (0.002/0.0005) = 5.36
THe answer is 5.36
#4 and #5:
To find pH given concentration of H+ or H30+
pH = - log (H+ or H30+ M)
To find pH given concentration of OH-
Since you already found the pH for this (in #4), you subtract #4's answer from 14.
14 - (pH) = pOH
Answer:
1.13 x 10²⁴formula units
Explanation:
Given parameters:
Number of moles of NH₄Cl = 1.87mol
Unknown:
Number of formula units = ?
Solution:
From mole concept;
1 mole of a substance contains 6.02 x 10²³ formula units
Now;
1.87 moles of NH₄Cl 1.87 x 6.02 x 10²³ = 1.13 x 10²⁴formula units
Answer:
eight oxygen atoms
Explanation:
This formula shows that in one mole of this compound, there are 3 moles of Ca atoms that combine with 2 moles of the PO4(phosphate) groups, which gives a total of 2 moles of P atoms and 8 moles of 0 atoms.
Answer:
Explanation:
The pressure is constant, so we can use Charles' Law to calculate the volume.
Data:
V₁ = 693 mL; T₁ = 45 °C
V₂ = ?; T₂ = 150 °C
Calculations:
(a) Convert temperature to kelvins
T₁ = ( 45 + 273.15) = 318.15 K
T₂ = (150 + 273.15) = 423.15 K
(b) Calculate the volume
