14 Students are given a solid sample and asked to determine whether the sample is

an element, compound, or mixture. One

student observes that the sample is:

• made up of particles of different

colors, sizes, and shapes

• some particles are softer than

others

• some shine while others appear dull

What can the students conclude about

their sample?

F It is an element.

G It is a compound.

H It is a homogeneous mixture.

J It is a heterogeneous mixture.

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 :

what are the statements