A reaction vessel inside a calorimeter contains 150 g of water at 19C. A reaction takes place in this chamber, after the reaction is complete the temperature of water is 29C. HOw many Joules were released/abosrbed during this reaction.

If you open the bottle of perfume then nothing but the smell will come out of it and yes it is a type of gas smell because it’s say it in english so i can understand better and you

Yes it would be a physical change.

☆ionisation energy increases across a period from na -> ar☆ionisation energy decreases down a group from li -> fr☆ionic radius decreases across a period from na -> cl☆ionic radius increases down a groupfrom f -> ii hope it clarifies your doubts