Why has the maximum allowed percentage of carbon monoxide been decreased for newer cars

Litmus paper is made from water-soluble dyes which are extracted from lichens. this paper is used as an acid-base indicator. which of these common household substances would turn blue litmus paper red? a) bleach b) lye c) soap d) vinegar

What is the relationship of air masses and the temperature of oceans?

Find the number of grams of hcl needed to react completely with .50 moles of magnesium.