Answer:
D
Explanation:
Elements in the same group of the periodic table do not have the same atomic size.
Answer:
3.53 g
Explanation:
To convert from atoms to moles, you need to know Avogadro's number. Avogadro's number (6.022 × 10²³) is how many atoms there are in one mole of a substance. Use this to convert.
(1.97 × 10²² atoms) ÷ (6.022 × 10²³ atoms/mol) = 0.0327 mol
Now that you have moles, use the molar mass to convert to grams.
(0.0327 mol) × (107.87 g/mol) = 3.53 g
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
The answer is 5.4! I found it on a an online calculator!