Litmus "Lecanora tartarea" (Norway, Sweden), "Variolaria dealbata", "Ochrolechia parella", "Parmotrema tinctorum", and "Parmelia". Currently, the main sources are "Roccella montagnei" (Mozambique) and "Dendrographa leucophoea" (California). The main use of litmus is to test whether a solution is acidic or basic. Wet litmus paper can also be used to test for water-soluble gases that affect acidity or alkalinity; the gas dissolves in the water and the resulting solution colors the litmus paper. For instance, ammonia gas, which is alkaline, turn the red litmus paper blue. Blue litmus paper turns red under acidic conditions and red litmus paper turns blue under basic or
SAT Subject Test in Chemistry laboratory concepts can simply be memorized beforehand. Some lab-based questions use diagrams, and thus it is helpful to know what common glassware looks like and how the different pieces are used. Like most of the SAT Subject Tests, the Chemistry SAT Test is relatively difficult. It tests a very wide breadth of content and expects students to formulate answers in a very short period of time. Many high school students find themselves picking up extra resource material, like prep books and online aids, to help them prepare for the SAT Chemistry test. While the test is challenging, there are distinctions