Use the table to identify the phase and phase changes of the elements under the given conditions. write the name of the substance, phase, or phase change.

when the temperature in a room increases from
25°c to 33°c,
changes from a solid
to a liquid.
in a lab, methane and nitrogen are cooled from
-170°c to -200°c. the methane freezes and the
nitrogen
.
when gold is heated to 2,856°c it changes from a liquid to a

Answers:

1. When the temperature in a room increases from25°C to 33°C, galium changes from a solid to a liquid.

2. In a lab, methane and nitrogen are cooled from -170°C to -200°C. The methane freezes and the nitrogen condenses.

3. When gold is heated to 2,856°C it changes from a liquid to a gas

Explanations:

The melting and boiling point of the substances permit to state whether a susbstance will be solid, liquid or gas at certain conditions (temperature in this case).

Melting point: is the temperature at which a solid becomes liquid.

Boiling point is the temperature at which a liquid becomes gas.

Hence:

The names of the phase changes dealt with in this question are:

With that let us go through the three statements:

1. When the temperature in a room increases from25°C to 33°C,

changes from a solid to a liquid. galium.

You need to find in the table a substance whose melting point is between 25°C and 33°C.

This is Gallium, whose melting point is indicated to be 30°C, meaning that at 25°C it is solid and at 33°C it is liquid.

2. In a lab, methane and nitrogen are cooled from -170°C to -200°C. The methane freezes and the nitrogen . condenses.

Since the boling point of nitrogen is - 196°C, at  -170°C nitrogen is gas.

Since, the melting point is - 210°C, at -200°C, nitrogen is liquid.

So, nitrogen condenses when it is cooled from - 170°C to - 200°C.

3. When gold is heated to 2,856°C it changes from a liquid to a . gas.

Since, 2856°C is the boiling point of gold, it will start fo pass from liquid to gas at this temperature.

c.

explanation: