requirement --> requirements
qualification -- qualifications
query -- queries

Are the above nouns are countable nouns?
Can I add "s" after these nouns?

Are there any good way or dictionary which can help us to determine if a particular abstract noun is a countable or uncountable noun.
Those nouns are countable.
Most good dictionaries show when a noun is countable or uncountable by having the letter 'C' or 'U' next to it. Try the Oxford Advanced Learner's Dictionary. It shows you this.
Yeah, they are countable nounsEmotion: smile

It depends on the situation, sometimes an abstract noun can be defined as countable if you mean different thing.

eg time

You can make it a countable noun if you refer to the particular time frame.

eg. I came in several times before and each time I saw different questions postedEmotion: smile
Students: Are you brave enough to let our tutors analyse your pronunciation?
 Woodward's reply was promoted to an answer.
Thank you so much!!!!!!!!!!Emotion: big smile