(CNN) -- An all-female jury will start hearing the murder case against Florida neighborhood watch captain George Zimmerman next week, with opening arguments in the closely watched trial set for Monday.

The jury was selected Thursday afternoon after defense attorney Mark O'Mara completed his question-and-answer session with the potential jurors. Opening statements are scheduled to begin Monday morning, Judge Debra Nelson said Thursday.

The prosecuting and defense attorneys referred to the jury members as five white women and one black or Hispanic woman. CNN does not have access to the juror questionnaires and cannot confirm the ethnicities of the jurors.

Four alternate jurors -- two women and two men -- will hear the case as well. Nelson asked Zimmerman if he agreed with the jurors selected to serve on the panel, and he said he did.

Zimmerman, a former neighborhood watch captain, is charged with second-degree murder for killing 17-year-old Trayvon Martin in Sanford, Florida, on the night of February 26, 2012. He says he shot the teenager in self-defense, but prosecutors accuse him of unjustly profiling and killing Martin.

An initial decision by police not to pursue charges in the case led to the dismissal of the town's police chief and sparked fresh debates about race relations and gun laws in the United States. Zimmerman is Hispanic; Martin was African-American.

O'Mara began the day by explaining the definition of reasonable doubt to the jury pool. He said it's a complicated concept that even "third-year law students" can have difficulty understanding.

O'Mara questioned the 40 potential jurors about a variety of topics, including their beliefs about gun ownership and their thoughts on self-defense.

O'Mara pointed out that Florida law states that there is no duty to retreat when being threatened, but Nelson admonished O'Mara, saying she did not want the attorneys interpreting the law for the jurors. Nelson then read to the jury the strict definition of justifiable homicide that they must consider during deliberations.

Justifiable homicide is a killing where no criminal liability can result, such as when someone acts in self-defense to protect himself or another person.

O'Mara finished his questioning of the jury before Nelson broke for lunch. When court resumed Thursday afternoon, the attorneys began the process of whittling down jury pool to the six jurors and the four alternates needed for the trial.

Under Florida law, six-person juries hear all criminal cases except capital offenses. The charges against Zimmerman do not make it a capital case.

Both sides had the chance to keep or strike jurors. Each side had 10 peremptory strikes -- 10 opportunities to eliminate potential jurors without having to disclose their reasons -- and an unlimited number of strikes "for cause," for such reasons as bias or hardships.

Later Thursday, attorneys were to resume the hearing to decide the admissibility of technology used to analyze the screams on a 911 call from the night of the shooting.

The technology may be key to the prosecution's case, because their experts' testimony may be able to shed light on what was said between Zimmerman and Martin moments before the teenager was shot.

If the analysis indicates Martin screamed for help, it could hurt the credibility of Zimmerman's claim that he acted in self-defense.

The law states that for technology to be admissible, it must be "generally accepted" in that particular field. Zimmerman's attorneys are arguing the technology does not satisfy that threshold.

On June 6, defense expert Hirotaka Nakasone, an audio engineer for the FBI, expressed his doubts about using the recordings.

"A screaming voice is too far for us to address," Nakasone said. "It might mislead in the worst case."

CNN's Grace Wong and Rich Phillips contributed to this report.