Answer:
Hi There! I'm new so I hope I get This Right! ^^
Explanation:
double blind test. the control group receives a placebo. Why is a placebo used in a double-blind test? so that the effects on people in two different groups can be compared.
happy To Help! ^^
P = nRT/V
P = 3.5 x 10^-3 x 0.082 x 298 /0.5
P = 0.171 m Hg
P = 171 mm Hg
hope this helps