If you have a landlord, that has keys to every other apartment and enters them at will, with no notice to the tenant of that apartment. Do I have to give her a key because I'm afraid she will enter and things will g missing.

Generally, the landlord has a master key that allows them to access all the apartments. However, some apartments locks do not key like that and so the landlord will have a separate key for every apartment. Why do you have to give the landlord a key? The landlord should have had two keys already - one for his or her own land one for you.

If that is not the case, yes, you do need to give the landlord a key. That is so, if there was an emergency such as a fire or water or other maintenance emergency, they can enter your apartment. No, they cannot just enter free will. You would need to give them permission to enter your apartment when you are not home. Check your lease about that. If you do not see something regarding that on your lease, then write them a letter concerning that. You do not wish anyone in your apartment without your presence or explicit permission. Sign it in front of a notary, have it notarized, then send it certified mail. Keep a copy.

That being said, that still does not give you 100% guarantee that the landlord will not come in when you are gone. But it does give you some footing. Also check your local renter's rights association to see what their advice would be.

A landlord is allowed keys to all of his properties. And yes you will be allowed to furnish him a key. For most issues, he needs to give a 24 hour notice that he will be in the apartment, for example I tell people on Monday that on Tuesday I would be in to spray for bugs, or be in to inspect the property, they do not have to give an exact time,

For emergancy they are allowed to come in at any time. For example, water running out of home, a report of a problem in the home and so on.