Bonsoir les amis ,demain j'ai un examen de chimie en solution et je veux bien que vous m'aider à faire ce exercice s'il vous plait calculer la qantite de nacl et de l'eau nécessaire pour l'obtention de 250g solution de nacl avec le pourcentage massique 10%

Dans 250 g de solution il y a 250×0,1 = 25g de chlorure de sodium.

Masse d'eau: 250g-25g = 225 g

masse volumique de l'eau 1 g cm-3 ; volume d'eau : 225 mL.

out of these options:

ability to burn paper

pure sodium reacting violently with water

the boiling point of water

helium does not tend to react with anything

i would say this is a physical property:

helium does not tend to react with anything

why? :

i said helium does not tend to react with anything because well, it reacts to ! but ability to burn paper, pure sodium reacting violently with water, & the boiling point of water are chemical or

physical properties: the properties of a substance that can be observed without changing the chemical makeup of the substance

chemical properties: properties of a substance relating to the chemical nature and reactivity of the substance

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 :