How many grams of nacl are required to make 500.0 ml of a 0.25 m nacl standard solution?

Lewis structure and molecular geometry for nh2cl

What is the number of moles of chemical units represented by 9.03x10^24? and how do i show work? (dumb it down )

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.