what kind of party is it
"Para que clase" in Spanish translates to "for what class" in English.
what do you have to do in the spanish class
"What class do you like more, Spanish class or English class?"
This means "At what time do you have Spanish class".
Which you always have to do in the Spanish class OR What do you always have to do in the Spanish class (if with a question-mark)
When is the Art class?
This mean "Are you in The Spanish Class?" in English.
what is in that class
Tengo que ir a mi próxima clase.
Que clase tienes en la quinta hora = What class do you have on fifth period?
It means What is your favorite class and why?
tengo que tenerte en la clase de espanol