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 'relationship analysis questions'. The SAT Subject Test in Chemistry is currently the only SAT that incorporates the relationship analysis questions. Relationship Analysis Questions require the student to identify the truth value of two statements. If both statements are true, the student will then have to analyze the relationship between the two statements to see if the second statement correctly explains the first statement. The last 47 questions numbered 24-70 are standard multiple choice questions. The Metric System of measurement is used, rather than United States customary units. This is widely because students across the world take SAT Subject Tests, not