Is the following true or false? most of the samples of matter are mixtures

How many moles of air are there in a human lung with a volume of 2.4 l at stp? explain your answer

Stage in which a typical star has completely stopped fusion

When hydrochloric acid reacts with potassium hydroxide solution, the following reaction occurs. hcl (aq) + koh (aq) h2o (l) + kcl (aq) the reaction gives off heat energy, so it is an reaction.