Matter Quick Check 23-24

In making a pizza, which process involves a chemical change?

• mixing spices for the sauce
• slicing pepperoni for the topping
• spreading cheese on the pizza
• baking the dough to form the crust

Which of these containers is not a pure substance?

• Container A
• Container B
• Container C
• All three containers hold a pure substance.

Which statement is correct about air?

• Air is made from pure oxygen gas.
• Air is a mixture of about 80% Nitrogen gas and about 20% oxygen gas.
• Air is a heterogenous solid.
• Air is a mixture of about 50% Nitrogen gas and about 50% oxygen gas.

Which of the models represents a pure molecule? (Each circle represents an atom.)

• Container A
• Container B
• Container C
• All three containers represent a pure compound.
• Containers A and C represent a pure compound.

Carlos was asked to bring an example of a mixture into class. Which of the following could Carlos bring as his example?

• Sugar
• Salt
• Salt Water
• Cold Water

What is true about lemonade?

• Lemonade is a pure substance.
• Lemonade is made from the lemonade chemical.
• Lemonade is a mixture.
• Making lemonade involves a chemical reaction.

What is true about the ocean?

• The salt in the ocean reacts with the water in the ocean to form a new ocean molecule.
• The salt water solution in the ocean is a mixture of salt and water.
• Ocean water is less dense than water in a lake.
• The salt water in the ocean is a pure substance.

Is nitrogen gas (shown below) a molecule, compound, both, or neither?

• Molecule
• Compound
• Both
• Neither

How many atoms are in a fructose molecule?

• 3 atoms
• 12 atoms
• 18 atoms
• 24 atoms

Which of the following is an example of a physical change but NOT a chemical change?

• A log gives off heat and light as it burns.
• A tree stores energy from the sun.
• A penny lost in the grass slowly changes color.
• A water pipe freezes and cracks.