What is the mass in grams of 450 ml of ph3 at stp conditions

The  mass  in grams   of 450 ml  of PH3   at STP  condition   is   0.6794 grams

Explanation 

mass   PH3= molar mass of PH3 x moles  of PH3

molar mass = 30.97 +(1x3)= 33.97g/mol

find the  number of moles of PH3  at STP

at  STP  1  moles  = 22.4  L
convert  450 ml to  liters =  450/1000 =0.45 L  therefore what  about 0.45 L

= (1mole x  0.45L)/22.4l  = 0.02 moles

mass  is therefore = 0.02 moles x  33.97 = 0.6794 grams

Read the sentences below in 1962, i tried to enroll as the first black student at the university of mississippi. the governor of mississippi blocked my entrance which best describes the verbs used in the sentences? o they are past tense verbs, which are often used in narrative essays o they are past tense verbs, which are not often used in narrative essays. o they are future tense verbs, which are often used in narrative essays o they are future tense verbs, which are not often used in narrative essays.

Reducing agents  oxidized by the reaction