Unit 2 Review Flashcards + I Used To Think Concepts

yes

Are melting point and freezing point the same?

no

Are things that are boiling always hot? Are things that are frozen always cold?

Vibrating (moving) atoms arranged in an orderly way with spaces in between them (the spaces are empty)

Boris and his friends have a magnifying glass powerful enough to see atoms of tiny crystals of salt, they would see what?

Physical: Green, odorless, powdery Chemical: Reaction with heat

Give one example each of a physical and chemical property of copper carbonate.

Physical: White, crystalized, odorless Chemical: No reaction w/heat

Give one example each of a physical and chemical property of sodium chloride.

Bromine has two atoms, one element (Bromine), and is an element.

Identify the number of atoms, the names of the elements in the molecules, and whether or not the molecule is an element or compound. The molecule is Br2.

Caffeine has twenty-four atoms, four elements (carbon, hydrogen, nitrogen, and oxygen) and is a compound.

Identify the number of atoms, the names of the elements in the molecules, and whether or not the molecule is an element or compound. The molecule is C8H10N402.

Brass has five atoms, two elements (Copper and Zinc), and is a compound.

Identify the number of atoms, the names of the elements in the molecules, and whether or not the molecule is an element or compound. The molecule is Cu3Zn2.

stayed the same because it is a closed system

Jake has a closed container with a bunch of wet nails. He measures its mass. He leaves it alone for the week and then comes back and finds the nails have rusted. He decides to measure it. Will the mass have increased, decreased, or stayed the same?

The characteristic properties would be: 1. Density 2. COA 3. Melting/freezing point 4. Boiling point 5. Reaction to heat

Mr. Markov has a mystery substance. What properties could you use to identify that substance?

Heat from the air immediately started transferring to the ice. As the air around the ice lost thermal energy, water vapor in the air reached its condensation point and became a liquid.

Mrs. Wendell took a sealed plastic container of ice cubes out of freezer. The outside of the container was dry and she set it on the counter. Half an hour later she noticed the ice had melted inside the container. The container was full of water. A small puddle of water had formed on the countertop around the outside of the container. Where did the puddle of water come from?

Physical: Placing flour in measuring cups Dissolving sugar because it does not change molecules Chemical: Baking the bread Letting the bread rise

Suppose Ms. Odle is baking bread. She measures out and combines the ingredients. She kneads the dough. She then leaves the dough to rise for a few hours. Finally, she bakes the bread. Which of the above steps are physical changes? Which of the above steps are chemical changes?

solid

The melting point of bolognium is -20 degrees Celsius. It's boiling point is 100 degrees Celsius. What phase will bolognium be at -30 degrees Celsius?

gas

The melting point of foosium is 70 degrees Celsius. It's boiling point is 140 degrees Celsius. What phase will foosium be at 150 degrees Celsius?

liquid

The melting point of unobtainium is -40 degrees Celsius. It's boiling point is 140 degrees Celsius. What phase will unobtainium be at 50 degrees Celsius?

true

The temperature that a substance boils at will be the same.

True, a compound is always a group of two or more atoms bonded together.

True or false: A compound is always a molecule.

False, a molecule could be a compound. A compound implies that the atoms that have formed together are different, but a molecule may be made up of two or more atoms of the same type.

True or false: A molecule is always a compound.

False, a single atom is not a molecule. A molecule is two or more atoms joined together.

True or false: A single atom is a molecule.

True, a single atom is an element. An element can be composed of a molecule or just an individual atom.

True or false: A single atom is an element.

False, an element is not always a molecule because an element can exist as a single atom (which does not count as a molecule).

True or false: An element is always a molecule.

false

True or false: an atom's nucleus is made up of molecules.

true

True or false: atoms take up mostly empty space.

true

True or false: bread is made up of one or more molecules.

The same - boiling temperature should not change overtime, boiling temp. is a characteristic property

We start to boil water for pasta. When the water is boiling, we record the temperature. We forget about it and come back later. The temperature is the same, increasing, or decreasing?

the same

We take a closed bag of ice out of the freezer. Without opening the bag, you let the ice melt. Is the amount of mass the same or different?

stays the same

When stearic acid freezes, the temperature (stays the same, increases, or decreases)

stays the same

When water boils, the temperature (stays the same, increases, or decreases)

Ice melts because heat energy is absorbed from the air. The heat causes molecules to move and they cannot stick together the way they did during the solid state.

Why does ice melt?

Ice doesn't melt immediately because phase changes occur where there is a loss or gain of energy and molecules move faster or slower. This is not an instantaneous process.

Why doesn't ice melt immediately when you put it in a soft drink?

Yes, an atom retains the properties of its element

Would atoms of a penny be copper-colored?