In the lab, a 156 g sample of unknown compound KClOx was completely decomposed to produce 50.4 L of O2 (g) at STP and an unknown amount of KCl. What is the value of X

2

Explanation:

Step 1: Write the generic decomposition reaction

KClOₓ ⇒ KCl + O₂

Step 2: Calculate the moles of O₂

At STP, 1 mole of an ideal gas occupies 22.4 L.

50.4 L × 1 mol/22.4 L = 2.25 mol

Step 3: Calculate the mass corresponding to 2.25 moles of O₂

The molar mass of O₂ is 32.00 g/mol.

2.25 mol × 32.00 g/mol = 72 g

Step 4: Determine the value of x

Every 156 g of KClOₓ there are 72 g of oxygen. The mass percent of O is:

%O: 72 g/156 g × 100% = 46.2%

In KClO, the mass percent of O is: 32.00 g/90.5 g × 100% = 35.4%

In KClO₂, the mass percent of O is: 64.00 g/138.5 g × 100% = 46.2%

Then, x = 2

"among the transition metal elements, manganese and zinc have a slight lowering of electronegativities. the reason behind this is that the nuclear charges of these elements are slightly weaker than the other transition metal elements due to the way their valence electrons are filled up. both manganese and zinc have their valence electrons filled up to the 4th shell with 1 pair of electrons (4s2) completely occupying it. although the electrons in the 3rd shell (3d) are yet to be paired since the outer most shell is filled up, the ability of the nucleus to attract electrons is lessened. hence,   the electronegativity (or the ability to attract electrons) is lessened."