A piezoelectric buzzer like the Murata PKM22EPP is not designed for use as a general purpose audio speaker, as it is optimized for 2000 Hz or 4000 Hz tones. With 1 kilohm series resistor, it does work acceptably for testing Arduino audio tone services.
void setup()
{
pinMode(2, OUTPUT);
// Sound a 300 millisecond beep in the foreground
tone(2, 1000);
delay(300);
noTone(2);
delay(1000);
// Sound a 300 millisecond beep in the background
tone(2, 1000, 300);
delay(1000);
tone(2, 400, 1000); // Low tone will be replaced immediately
tone(2, 2000, 300); // High tone replaces low tone
}