Study questions platform-wide or filter by specific tests with correct answers revealed.
K$_2$HgI$_4$ is 40% ionized in aqueous solution. What is the van't Hoff factor ($i$)?
K$_2$HgI$_4$ dissociates as: $\text{K}_2\text{HgI}_4 \to 2\text{K}^+ + \text{HgI}_4^{2-}$ (3 particles total if fully ionized)
Degree of ionization $\alpha = 0.40$, total particles per formula unit if fully ionized = 3.
$i = 1 + (n-1)\alpha = 1 + (3-1)(0.40) = 1 + 0.80 = \mathbf{1.80}$
A body starts from rest and moves under constant acceleration for 20 s. It covers distance $S_1$ in the first 10 s and $S_2$ in the next 10 s. Then $S_2$ equals:
Using $s = \dfrac{1}{2}at^2$ (from rest):
$S_1 = \dfrac{1}{2}a(10)^2 = 50a$
Total in 20 s: $S_{\text{total}} = \dfrac{1}{2}a(20)^2 = 200a$
$S_2 = 200a - 50a = 150a = 3 \times 50a = \mathbf{3S_1}$
Sign in to join the conversation and share your thoughts.
Log In to Comment