i am a little conused with the following

yemek ve yemeği

yemek yiyorum

yemek salonu nerede?

bu yemek siçak?

are these sentences correct?

but how do i use yemeği?

also the differnce between iş and calismaya when talking about work.

işin var?

sen calimayi bitirdin mi?

* Bu yemek sıcak mı?

The rest are correct

Yemeği is usually added after another word. Such as, akşam yemeği (dinner), düğün yemeği (wedding dinner), patates yemeği (potato dish), Türk yemeği (Turkish food), etc.

Generally, "iş" is used as business or work. Also when talking about job, you use iş. 

But çalışmak is a verb, and used as "to work" (or to study). And other words may be derived from it.

Another possibility,

Food is the subject:

Yemek güzel - The food is good

Food is the object (applies to some verbs):

Yemeği sevdik - We liked the food

thank you both for your answers and explanations. now i understand