Hydrogen powered cars create less pollution than gasoline powered cars when driven. what might be a challenge to using hydrogen as a fuel?

Liv sheldon given the balanced equation for an organic reaction: c2h2 + 2cl2 → c2h2cl4 this reaction is best classified as *

Significant figures are digits read directly from the measuring instrument plus one more digit, which is __ by the observer.

Sally is making a model of a magnesium atom with an atomic mass number of 24 for her chemistry class. she has foam balls for the protons, neutrons, and electrons. she has added 6 neutrons to her model so far. how many more neutrons does she need to add to complete her neutral atom of magnesium?