Which of these elements is a noble gas? a. hydrogen (h) b. barium (ba) c. nitrogen (n) d. krypton (kr) e. bromine (br)

Look at the spectrums of a star moving towards earth and a motionless star. which of these is a correct inference that can be draw from the observation of the two spectrums? (2 points) the spectrum of a motionless star is difficult to be viewed separately using oridinary telescopes. the spectrum of a motionless star is identical to the spectrum of a star which moves towards earth. the spectrum of a star shifts towards the red region when the star moves towards earth. the spectrum of a star shifts towards the blue region when the star moves towards earth.

Which of these expressions are correct variations of the combined gas law? p1v1t2 = p2v2t1 both

Answer asap need it by wednesday morning calculate the ph of 0.02m hcl best answer will be brainliest