Student Sabita Thanwani was found with neck injuries in the halls of residence in Sebastian Street, Clerkenwell.
Police and medics went to Arbour House at about 5.10 am on Saturday but she died at the scene.
Police have arrested Maher Maaroufe, 22, on suspicion of murdering Ms Thanwani. He remains in police custody.
In a statement, Ms Thanwani’s family said: “Sabita was our daughter. Our angel.
“Her life, that we hoped would be long, was cut tragically short. She was ripped away from those who loved her so very dearly; her mum, dad, brother, grandparents, extended family and friends.
“We can only pray that lessons will be learnt and that somehow, there will come a day when girls and women are safe.
“Sabita was the most caring and loving person we have ever known. She inspired us every day of her precious 19 years of life. Her mission was to help everyone.
“Her whole life was ahead of her, a life where her radiant smile and incredible heart could only spread warmth and kindness.
“In her short life, she helped so many. Sabita was pure and did not see bad in anyone, because there was no badness in her own awesome heart.
“We will never ever stop loving or missing our beautiful, irreplaceable Sabita. The girl that was an angel upon the earth is now an angel in heaven.”
Ms Thanwani was studying psychology at City, University of London, which is near to the student accommodation where she died.
Maaroufe was arrested by officers in Clerkenwell area after a police appeal to trace him.
He had been in a relationship with Ms Thanwani at the time of her death, police said.
A post-mortem examination has also been arranged.