Give the oxidation number of the element indicated for each compound.

a) carbon in Na2C2O4
b) nitrogen in HNO3
c) sulfur in H2SO4
d) carbon in HCO3 −
e) manganese in KMnO4
f) chromium in Cr2O7 2−

a. C: +3 ; b. N: +5 ; c. S:+6 ; d. C: +4; e. Mn: +7 ; f. Cr: +6.

Explanation:

Global charges in molecules is 0

You sum all the oxidation states to determine the oxidation state for the compound.

Na₂C₂O₄ → Sodium oxalate → Global charge: 0

Oxidation state for C: +3

HNO₃ → Nitric acid → Global charge: 0

Oxidation state for N: +5

H₂SO₄ → Sulfuric acid → Global charge: 0

Oxidation state for S: +6

HCO₃⁻  →  Bicarbonate → Global charge: -1, this is an anion

Oxidation state for C: +4

KMnO₄ → Potassium permanganate → Global charge: 0

Oxidation state for Mn: +7

Cr₂O₇⁻ → Anion dichromate → Global charge: -2

Oxidation state for Cr: +6

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.

it means there are 3 atoms of oxygen