There are 118 elements in the periodic table. what is a likely estimate of the number of compounds formed by these elements? 118 compounds as each compound is made of one element 236 compounds as each compound is made of two elements far greater than 118 because elements combine in various ways 59 compounds because elements pair up with each other to form all compounds

Answer is: Far greater than 118 because elements combine in various ways.

Number of compounds is more than 30 millions.

A chemical compound is a substance composed of many identical molecules.

Element bonded to an identical chemical element is not a compound.

For example, emerald (beryl) is chemical compound (beryllium aluminium cyclosilicate) with the chemical formula Be₃Al₂(SiO₃)₆.  

Other example, molecule carbon(IV) oxide (CO₂) is made of one carbon atom and two oxygen atoms bonded with covalent bonds.

Element is pure substance is made of only one type of atom (element) or only one type of molecule, it has definite and constant composition with distinct chemical properties.

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 :