The chemical equation below represents a reaction between an acid and a metal. Zn + 2 HCl → ZnCl2 + H2 How many moles of HCl would be required to produce 2 moles of hydrogen gas?

Label a-f based on the table using c for concentrated and d for dilute

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.

What are scientists who study fossils called? ( a ) astronomers. ( b ) biologists. ( c ) geologists. ( d ) paleontologists.