Balance Cr2O3+Mg -->Cr + MgO

Balancing means there are equal amount of molecules on each side, both reactant and products. This is a method I like to do.

Under, I count how many molecules are in each side.

              Cr2O3+Mg -->Cr + MgO

Cr:              2                    1

O:                     3                            1

Mg:                         1                 1

Let's guess and make the number of oxygens equal on both sides.

              Cr2O3+Mg -->Cr + 3MgO

Cr:             2                    1

O:                      3                           3       EQUAL

Mg:                          1                   3

See what we did there? We multiplied the MgO on the products side by 3 so we can have 3 oxygens. Now let's multiply the Mg on the reactants by three so Mg AND O can be equal.

                Cr2O3+3Mg -->Cr + 3 MgO

Cr:              2                      1

O:                      3                               3        EQUAL

Mg:                         3                        3          EQUAL

Finally, we just need to multiply the loner Cr in the products side by two to make it equal for all elements.

                 Cr2O3+3Mg -->2Cr + 3 MgO

idk i’m struggling too

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.