401. The main buffer system of the human blood is____________?
A. H2CO3 – HCO3
B. H2CO3 – CO32-
C. CH3COOH – CH3COO–
D. NH2CONH2 – NH2CONH+

402. The most commonly used bleaching agent is_________?
A. alcohol
B. carbon dioxide
C. chlorine
D. sodium chlorine

403. The heat required to raise the temperature of body by 1 K is called___________?
A. specific heat
B. thermal capacity
C. water equivalent
D. None of the above

404. The mass of P4O10 that will be obtained from the reaction of 1.33 gram of P4 and 5.07 of oxygen is___________?
A. 2.05 gram
B. 3.05 gram
C. 4.05 gram
D. 5.05 gram

405. The octane number of zero is assigned to____________?
A. 2-methyl octane
B. n-heptane
C. iso-octane
D. 3-methyl octane

406. What is the mass percent of silver in silver notrate, AgNO3?
A. 64.5%
B. 65.6%
C. 63.5%
D. 61.5%