what is the difference between muslims and arabs

Arabs are (mostly) Muslims, who speak Arabic.

Muslims worship the prophet Mohammed.

For a better definition of Muslim, see

http://en.wikipedia.org/wiki/Muslim

Traditionally, one was considerted a Muslim if you publically pronounced this:

Ash-hadu an laa ilaha illa-lah Wa ash-hadu anna Muhammadan rasulullah

"I bear witness there is no deity worthy of worship except Allah and I bear witness, Muhammad is His final messenger".
The problem with that it allows all sorts of folks to be good muslims: murderers, terrorists, thiefs, airplane bombers, and so forth.
Most Muslims agree that to be muslim, one has to say the above.
However, a few years ago, some muslims concerned with ethics, attempted to redefin what a muslim Is.

It said you had to be active in one of the major schools of thought on Islam:
1. Sunni Hanafi
2. Sunni Hanbali
3. Sunni Maliki
4. Sunni Shafi'i
5. Shia Ja`fari
6. Shia Zaidiyyah
7. Ibadi
8. Zahiri
All the other (sects) were "prohibited"
http://en.wikipedia.org/wiki/Amman_Message
Personally, I am not certain this edict will stick.
Time will tell.

Muslims and Arabs are two distinct concepts that often get misunderstood or conflated.

Muslims: Muslims are individuals who practice the religion of Islam. Islam is a religion founded in the 7th century by the Prophet Muhammad. Muslims believe in the teachings of the Quran, which they consider to be the word of God as revealed to Muhammad.

Arabs: Arabs, on the other hand, are an ethnic group and a linguistic group that primarily inhabit the Arab world, which comprises countries in the Middle East and North Africa. Arabic is the primary language spoken by Arabs. However, it's important to note that not all Arabs are Muslims, and not all Muslims are Arabs.

To differentiate between Muslims and Arabs, it's essential to understand that being an Arab refers to a person's ethnicity or linguistic background, while being a Muslim refers to a person's adherence to the Islamic faith.

To determine if someone is Arab, you would typically consider their ancestral heritage, language, cultural practices, and the region they come from. On the other hand, to determine if someone is a Muslim, you would need to ask about their religious beliefs, practices, and observances.

It's important to avoid generalizations and stereotypes when discussing Muslims and Arabs, as both identities are diverse and encompass various cultures, languages, and religious practices.