Question 1
The definition of pH is pH = -log[H
3O
+], where [H
3O
+] is the hydronium ion concentration.
If [H
3O
+] = 1.2 × 10
-5, the pH, expressed to the correct number of significant figures, is:
◦ 4.92
◦ 4.9
◦ 5.08
◦ 5.1
Question 2
The density of air under ordinary conditions at 25 °C is 1.19 g L
-1. How many kilograms of air are in a room that measures
and has a 8.00 ft ceiling?
(exactly);
)
◦ 2.93
◦ 0.121
◦ 3.26 × 10
4◦ 0.0770
◦ 32.6