Define critical point.
Group of answer choices:
A. The temperature and pressure above which a supercritical fluid exists.
B. The temperature and pressure are equal.
C. The temperature and pressure below which a supercritical fluid exists.
D. The temperature and pressure are not equal.
E. The temperature and pressure where liquid, solid, and gas are equally stable and are in equilibrium.

A. The temperature and pressure above which a supercritical fluid exist.

Explanation:

The physical states of a substance under different temperature and pressure conditions is represented by a phase diagram. In this diagram, normally the pressure is represented on the y-axis while the temperature is present on the x-axis. There is a point on this diagram called the critical point, beyond this point the liquid and the gaseous phase become indistinguishable. When the substance surpasses the critical point, it is referred as a supercritical fluid.

From the above description, all the options other than A is false.

answer: the rate of diffusion increases with increase in temperature.

increase in temperature, increases the molecular/particles speed (kinetic energy. diffusion means movement of particles through the material.

generally, the heavier the particle the more it interacts with the environment and more the temperature matters. so higher temperature results in higher diffusion.

answer:

the answer is 6 valence electrons.

explanation:

valence is the # of electrons on the outer most shell of an atom.

oxygen has 6.

although, the valency of oxygen is 2, because it only needs to make 2 covalent bonds, or gain 2 electrons, to achieve the stable octet configuration of a noble gas.

that's it!

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