Please help me get the answer. I cannot see what the color difference is. Please help. The code has to be a 4 digit code with no spaces

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

Identify the electromagnets with poles that are reversed from the electromagnet shown above

Which statement is true about hcl? (5 points) select one: a. it is a salt because it increases the concentration of metallic ions. b. it is a salt because it is formed by the reaction of an acid and a base. c. it is an acid because it increases the concentration of hydroxyl ions. d. it is an acid because it increases the concentration of hydronium ions.