Which has more atoms: a 1-gram sample of carbon-12 or a 1-gram sample of carbon-13?
A) More information is needed.
B) They have the same number of atoms.
C) A one gram sample of carbon-13
D)* a one gram sample of carbon-12
What is the total number of protons and neutrons in a water molecule?
A) 10
B) 12
C) 15
D)* 18
E) none of these
Humidity is a measure of the amount of water vapor in the atmosphere. Why is humidity always very low inside your kitchen freezer?
A) because the frost in the freezer absorbs this moisture
B) because the kitchen freezer is most often sealed off from the atmosphere
C) because it is not possible for water to be in the gaseous phase at temperatures below 0°C
D)* At the cold temperatures of your kitchen freezer, water molecules in the vapor phase are moving relatively slowly, which makes it easier for them to stick to inner surfaces within the freezer or to other water molecules.
