Students can use to distinguish pure substances, such as elements and compounds with a constant composition, from other substances. a) color b) density c) particle size d) state of matter

Answer is: B) density.

Pure substance is made of only one type of atom or only one type of molecule, it has definite and constant composition with distinct chemical properties.

Mixtures are physical combinations of pure substances that have no definite or constant composition.

With constant composition density of pure substance is always the same and in other substances it can vary according the composition.

Density is a measure of mass per unit of volume.

The SI derived unit for density is the kilogram/cubic meter, but chemist usually use gram per cubic centimeter.

explanation:

i think option no d is the correct answer

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 :