Questions

True-False [Che-1M]

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4 questions · self-marked practice — reveal the answer and mark yourself.

Question 11 Mark
State whether the following statement is true or false:
Solid carbon dioxide is stored under low pressure.
Answer
False.
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Question 21 Mark
State whether the following statement is true or false:
Red brown bromine vapour diffuse into air in a gas jar but the colourless air molecules do not diffuse into bromine vapour.
Answer
False.
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Question 31 Mark
Sea water boils below 100°C. [True/ False]
Answer
False.

Explanation:

Pure water boils at 100 degrees Celsius under normal atmospheric pressure, but the Dead Sea surface is so low (more than 400 meters below "sea level") that water boils at about 101 degrees there. It does boil at a higher temperature because of the high amounts of non-volatile solids.

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Question 41 Mark
In pressure cooker water boils above 100°C. [True/ False]
Answer
True.

Explanation:

Food is cooked more quickly in a pressure cooker because at the higher pressure (1 bar/ 15 psi), the boiling point of water rises from 100°C (212°F) to 121°C (250°F).

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True-False [Che-1M] - Science STD 9 Questions - Vidyadip