What semimetal can form four single covalent bonds.

The right answer is Sillicon.

Silicon (Si) is the chemical element of atomic number 14. It is the most abundant element in the earth's crust after oxygen, or 25.7% of its mass, but it is comparatively only present in relatively small quantities in the material constituting the living.

It is a semi-metal, ie it does not meet all the criteria to be defined as being a metal.

It has four free electrons in the last orbit, so it is able to form four covalent bonds. (the carbon can form 4 covalent bonds but it is not a semi-metal)

answer: the value of enthalpy change will be -152.80 kj.

solution:

pressure = 1atm , temperature = = 298 k

given that pressure and temperature are same in both gases , the number of moles of both gases can be determined by the ideal gas equation.

according to reaction 3 moles no are reacting with 1 mol of ,then 0.49 mol of no will react with moles of ozone that is 0.16 moles of ozone. since, no is limiting reagent and is an excessive reagent.

enthalpy change for the reaction between the given volumes of the gases is :