A30.7 g sample of strontium nitrate, sr(no3)2•nh2o, is heated to a constant mass of 22.9 g. calculate the hydration number.

The difference of the sample mass and the heated sample mass is the amount of water which evaporated by heating process, then we can calculate:  

mass of H₂O = 30.7 -  22.9 = 7.8 g

then calculate the number of moles:  

number of moles of H₂O =  mass / molecular mass

number of moles of H₂O = 7.8 / 18 = 0.43 moles

So the hydration number is 0.43.

Sr(NO₃)₂ • 0.43 H₂O

that's just how they are

explanation:

you can't control another persons decisions, all you can do is ask that they respect yours. relationships are hard because you have to put the effort into making sure that another person feels seen, heard, and loved. as time goes on, it gets easier, you learn how to do these things without thinking. loving them becomes as easy as breathing, but every relationship will have fights, and sometimes it'll feel like you're drowning, but as long as you can talk it out and compromise, because that's truly what loving another person is, is compromise, then you'll be okay. movies and tv shows have glamorized and romanticized (pardon the pun) what a relationship would be like. real relationships aren't perfectly timed kisses in the rain, zero fights until one big one ends everything, 6 month anniversaries. real relationships are sleepy confused kisses when one person has to leave for work earlier than the other,   real relationships are having small disagreements, real relationships are messy and confusing, real relationships is knowing that even if you're relationship may not last forever and this may not be the person you're going to spend the rest of your life with, that you love them, and you would do anything to see them happy. so yes, relationships are difficult, but so are many other things, relationships can be amazing but also stressful, and not just romantic i'm also talking about platonic relationships (although the primary example here was romantic) sometimes is best to leave friendships behind, so remember, always do whats going to you be happy in the long run.

the correct name for the n3 ion is azide. azide is a polyatomic anion with a -1 charge and is written as n3 -1. it consists of three nitrogen atoms bonded together. hope i . let me know if you need anything else.