Which two reactions are faster than the others? A. Lead nitrate and potassium iodide react to form ellow
precipitate
B. Silver tarnishes in air that contains hydrogen sulfide.
C. Black powder in fireworks burns explosively to produce gases and
white light
D. Tron metal reacts with oxygen in air to form rust

Ineed to find the answer of this question because i dont understand it

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.

Find the number of moles of argon in 364g of argon.