PROPERTIES OF MATTER: Solubility, Boiling/Melting Point, Magnetism SC.8.P.8.4 Classify and compare substances on the basis of characteristic physical properties that can be demonstrated or measured: for example, density; thermal or electrical conductivity; solubility; magnetic properties; melting and boiling points; and know that these properties are independent of the amount of the sample. (Also assesses SC.8.P.8.3.) ESSENTIAL QUESTION: How can the physical properties of a substance help us reliably identify unknown substances?

BELL RINGER Theresa has a pile of sand grains and salt grains mixed together. She wants to separate the sand from the salt. What method can she use to separate these two substances? Heat the pile to 100oC so that part of the pile boils. Place a magnet over the pile to pull out the magnetic parts. Sift the pile through a screen with holes that are one centimeter wide. Stir the pile into a bowl of water, and then pour the water out of the bowl.

INTERACTIVE JOURNAL RIGHT SIDE

Solubility The ability of a substance to be dissolved into another substance.

Solubility Vocabulary: Solute: The substance that is dissolved into the solvent. Solvent: The substance into which the solute is dissolved. Solution: When the solute is dissolved into the solvent. (Homogeneous mixture).

Saturation Point: When the solution can’t dissolve any more solute. EX.) the Kool-Aid can’t dissolve more sugar, so it settles on the bottom.

Melting Point The temperature at which a substance changes from a solid to a liquid. Melting Point of Water= above 0°C

Melting Point

Boiling Point The temperature at which a substance changes from a liquid to a gas. Boiling Point of Water= above 100°C

Boiling Point

Magnetism A non-contact force that pulls on IRON & NICKEL & COBALT from a distance

INTERACTIVE JOURNAL LEFT SIDE

REVISITING THE BELL RINGER Theresa has a pile of sand grains and salt grains mixed together. She wants to separate the sand from the salt. What method can she use to separate these two substances? Heat the pile to 100oC so that part of the pile boils. Place a magnet over the pile to pull out the magnetic parts. Sift the pile through a screen with holes that are one centimeter wide. Stir the pile into a bowl of water, and then pour the water out of the bowl. *

YOU DO TIME!

YOU DO question #1 Jamal is combining salt with water in order to determine its solubility. He notices that after adding ten spoonfuls of salt, no more will dissolve into the water. Which statement best explains his observation? There is not enough solute added to the solution. The solution has reached its saturation point. The density of the salt is being changed. The state of the water is being changed. Correct Answer: B

YOU DO Question #2 Mario uses a hot plate to heat a beaker of 50mL of water. He used a thermometer to measure the temperature of the water. The water in the beaker began to boil when it reached the temperature of 100C. If Mario completes the same experiment with 25mL of water, what would happen to the boiling point? The water will not reach a boil. The boiling point of water will increase. The boiling point of water will decrease. The boiling point of water will stay the same. Correct Answer: D

YOU DO Question #3 Katie's teacher has given her a sample that contains a mixture of salt, sand, and iron filings. She is instructed to separate the mixture into the three individual components. What would be the best physical property to focus on for the first step in separating the mixture? Density Electrical conductivity Magnetism Melting point Correct Answer: C

How can density be used to reliably identify unknown substances? Exit ticket How can density be used to reliably identify unknown substances?