You can see a physical change always but not always a chemical
Yes because I went through college and learned this
N2 + 3 H2 -> 2 NH3
<span>Just use their stoichiometric coefficients (number before the chemical's name) from the balanced chemical reaction to make ratios and solve for the unknown. In this case, 2 moles of NH3 are produced for every 3 moles of H2. Thus, </span>
<span>7.5 moles H2 x (2 moles NH3 / 3 moles H2) = 5 moles NH3
</span>Thunderclan89
Answer:
limestone+heat=marble
sandstone+heat=metaquartzite
shale+heat=quartzite