A. Air expands, becomes less dense and rises when the temperature is high due to the increased kinetic energy. This causes the air molecules to move around much more so they are further apart.
1) is C because the arrows are pointing in so that means to squeeze
3) is A as the picture shows the dropper
# moles = mass (g) / Mr (relative atomic mass)
# moles = 458 / ((23*2)+32+(16*4)
# moles= 458 / 142 = 3.2253521126760...
= 3.23 moles
Answer:
4L
Explanation:
To obtain the volume of O2 at stp, first, we need to determine the number of mole of O2.
From the question given above,
Mass of O2 = 5.72g
Molar Mass of O2 = 32g/mol
Number of mole =Mass/Molar Mass
Number of mole of O2 = 5.72/32
Number of mole of O2 = 0.179 mole
Now, we can calculate the volume of O2 at stp as follow:
1 mole of a gas occupy 22.4L at stp.
Therefore, 0.179 mole of O2 will occupy = 0.179 x 22.4 = 4L
Therefore, the volume occupied by the sample of O2 is 4L
As we know, NaOH is a strong Base and completely dissociates in water as given below,
NaOH + H₂O → Na⁺ ₍aq₎ + OH⁻ ₍aq₎
So, the concentration of OH⁻ Ions will be the same as that the concentration of NaOH i.e. 0.018 M.
So,
[OH⁻] = 0.018 M