I.S homework 2

When will plants take in oxygen?
A. At night
B. During the day and at night
C. During the day
D. Never
Which of the following gases can relight a glowing splint?
A. Carbon monoxide
B. Carbon dioxide
C. Oxygen
D. Nitrogen
The colour of the hydrogencarbonate indicator without any carbon dioxide is
A. colourless.
B. purple.
C. red.
D. yellow.
Which of the following can be used to test for nitrogen?
(1) a burning splint
(2) hydrogencarbonate indicator
(3) lime water
A. (1) and (2) only
B. (1) only
C. None of the above
D. (1) and (3) only
Which of the following statements about nitrogen dioxide is INCORRECT? A. It is a poisonous gas.
B. It can cause brain damage in children.
C. It forms acid rain.
D. It causes lung diseases.
Green plants in darkness
A. release oxygen.
B. use up all carbon dioxide.
C. release carbon dioxide.
D. produce starch.
When there is a fire, fumes are all around. We need to crawl on the floor while escaping
(1) to avoid being hurt by falling objects.
(2) to avoid inhaling too much fumes and getting suffocated.
(3) because crawling requires less energy, and thus the demand for oxygen is lower.
A. (1) and (3) only
B. (2) and (3) only
C. (1), (2) and (3)
D. (2) only
The colour change of hydrogen carbonate indicator when it is moved from normal air to air with high carbon dioxide concentration is
A. from red to yellow.
B. from yellow to red.
C. from red to purple.
D. from purple to yellow.
The energy released in respiration can
(1) support life.
(2) maintain constant body temperature.
(3) serve as raw materials for the growth of skeletons.
A. (1) only
B. (1), (2) and (3)
C. (1) and (2)
D. (2) and (3)