what is hte molarity of solution preared by dissolving 5.68 grams of naoh in enough water to make 400 mL of solution

What is the molality of a solution that has 4 mol of kci in 0.800 kg of water

The answer for #3 is c but i don't know why

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.