Question

Substance X is placed in a cup. Its shape does not change. It is then placed on a plate; its shape still does not change.

Substance X is most likely a

solid.
liquid.
gas.
plasma.



Rahul sees a flock of birds. He watches as the flying birds land in neat little rows on several power lines. Which change of state does the motion of the birds most closely model?

melting
vaporization
deposition
sublimation



Which statement is a description of Charles’s law?

The temperature and volume of a gas are directly proportional when pressure is constant.
The temperature and volume of a gas are inversely proportional when pressure is constant.
The volume and pressure of a gas are directly proportional when temperature is constant.
The volume and pressure of a gas are inversely proportional when temperature is constant.



Sal drew the electron dot diagram of an aluminum atom as shown.

A l with 1 dot each above and right.

How should Sal correct his diagram?

He should add five more dots so that the atom obeys the octet rule.
He should add ten more dots so that all thirteen electrons are shown.
He should add a single dot below the symbol.
He should add one dot below and one dot to the left of the symbol.



Which describes a feature of the physical changes of all substances?

can dissolve in water
can conduct heat and electricity
rearranges atoms to form new substances
does not change the identity of a substance

Answer 1

1) solid — its shape stays the same regardless of the container.

2) deposition — like gas particles (birds in flight) becoming an ordered solid arrangement (lined up on the wires).

3) The temperature and volume of a gas are directly proportional when pressure is constant.

4) He should add a single dot below the symbol — Al has three valence electrons, so the Lewis dot should show three dots.

5) does not change the identity of a substance — physical changes do not produce new substances.