Chain of events, you submit a sales offer too seller with terms and conditions. Upon execution of contract both buyer and seller contractual obligated to executed agreement for performance. If one party does not perform based on contract there can be liable potential lawsuit filed against that party.
In contract - not knowing all particulars you have an executed contract.
"In contract" means that the seller of the property has accepted an offer. Sometimes the offer has certain conditions that must be met in order for the contract to be "solid" or closeable. Yor best bet is to contact your agent and have them ask the listing agent if other offers are being considered. If you have a strong interest in the property, be prepared to act immediately if the answer is yes.
If the seller wishes to stay with the first contract, your offer could be considered and accepted as a "back up" contract which would go into effect if the first buyer fails to perform or backs out of the agreement.