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

Fill in the Blank

How many unmarked bottles of liquid did the investigators come across at the crime scene? (Type a number in the box)

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.

Drag these tiles and drop them in the correct blank above

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.

Drag these tiles and drop them in the correct blank above

100

69

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!