1-2 PRE-LAB Using BP to Identify Unknown Liquids

Multiple Choice

Which of the following is true regarding the SOLVENTS you are going to attempt to identify?

• They are often used to restore or clean artwork.

• They can be used to dissolve paint.

• They are used to create mixtures.

• All of the above are true.

Multiple Choice

Which best describes the appearance of the two liquids you are going to identify?

• opaque, clear

• transparent, colorless

• transparent, reflective

• transparent, white

Multiple Choice

Which PHYSICAL PROPERTY are you going to use in order to determine the identify of the two liquids?

• melting point

• appearance

• boiling point

• density

Drag and Drop

As the temperature of liquid particles ​

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the liquid particles will ​

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faster and faster.

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slide by each other

vibrate

increases,

decreases,

Multiple Choice

Once they have gained enough energy, they will reach their boiling point. This is when they will

• escape their liquid neighbors as a gas.
• get stuck in one spot and vibrate.
• continue to slide past their neighbors.

Dropdown

Different types of particles have ​

Select answer

chemical compositions and ​

Select answer

boiling points.

Drag and Drop

A sample of liquid WATER must be heated to ​

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^oC in order for the liquid particles to start boiling (escaping as a gas). Hexane needs ​

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which is why hexane's boiling point is ​

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than water's.

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100

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less energy than water

lower

more energy than water

higher

Multiple Choice

In order to know when the unknown substances have reached their boiling points, you should look for :

• the first sign of bubbles forming anywhere in the sample.

• a steady stream of bubbles forming at the bottom of the sample

• a steady stream of bubbles forming at the top of the sample

• the last bubble to form and rise to the surface

Dropdown

Gas bubbles are ​

Select answer

They are filled with particles that have ​

Select answer

chemical composition as the particles in the liquid surrounding them.

Multiple Choice

What we really see when we notice a bubble is

• liquid particles that have solidified

• a space filled with nothing

• the border between the gas and the liquid surrounding it

Dropdown

A bubble rises to the surface of the sample because the gas particles​ zip around faster and

Select answer

than the surrounding liquid particles. This makes the bubble​

Select answer

dense than the surrounding liquid.

Dropdown

PHase changes such as boiling, condensing, melting, and freezing are PHysical changes which means the chemical composition of the particles involved ​

Select answer

change.

Multiple Choice

Which model represents a sample of hexane particles at a temperature BELOW its boiling point?

Multiple Choice

The red arrows in this model represent:

• the pressure exerted by the gas particles on the surrounding liquid

• the pressure exerted by the liquid particles on the gas particles inside the bubble

• the temperature of the gas particles inside the bubble

• the number of gas particles present inside the bubble

Multiple Choice

Does the chemical composition of a particle change when it boils and escapes from the sample as a gas?

• NO - the number and types of atoms that make up the particles does not change!

• YES - changing into a gas causes the number and types of atoms that make up the particles to change!