Answer:
Explanation:
Electronic configuration represents the total number of electrons that a neutral element contains. We add all the superscripts to know the number of electrons in an atom. The electrons are filled according to Afbau's rule in order of increasing energies.
The electronic configuration for given elements is as follows:
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
Our only unknown is the volume<span> of H</span>2(g<span>) . Our known variables are P,n,R, and T. </span>At STP, the temperature is 273K and the pressure is 1 atm. Rearrange the equation to solve for V: n×R×TP. V=2.20mol<span> ×</span><span>0.0821L×atm mol×K ×273K 1atm. V=49.3L</span>
342.14 g/mol
Molar mass of Al= 26.98
Molar mass of S=32.06
Molar mass of O=16.00
(26.98)2+(32.06+(16.00×4))3=342.14