Unit 1: Matter and Solutions TEST

First and Last Name:

Look at the two images of molecules. Which of the following statements best compares the two images?

• A. Images A and B are both compounds because they have more than one atom.
• B. Image A is a compound because it has different types of atoms, and image B is an element because it has one type of atom.
• C. Image A is an element because it has one type of atom, and image B is a compound because it has different types of atoms.
• D. Images A and B are both elements because they have more than one atom.

Aluminum fluoride is a compound commonly used in ceramics. The chemical formula for aluminum fluoride is AlF3. The Periodic Table shows the elements used in the compound. Which of the following is true regarding aluminum fluoride?

• A. Aluminum fluoride contains 3 atoms of aluminum and 3 atoms of fluorine.
• B. Aluminum fluoride contains 1 atom of aluminum and 1 atom of fluorine.
• C. Aluminum fluoride contains 1 atom of aluminum and 3 atoms of fluorine.
• D. Aluminum fluoride contains 3 atoms of aluminum and 1 atom of fluorine.

Based on the chemical formula, which statement best describes NI3

• A. Based on the chemical formula, there are 3 atoms in one molecule of NI3.
• B. Based on the chemical formula, there are 6 atoms in one molecule of NI3.
• C. Based on the chemical formula, NI3 is composed of atoms of the same elements.
• D. Based on the chemical formula, NI3 is composed of atoms of different elements.

Which of these molecules represent compounds? Select all that apply.

• A. H2O
• B. H2
• C. AlF
• D. CO2
• E. S8

Amanda wants to make a cake. She measures sugar, eggs, oil, flour, and flavorings. She mixes the ingredients together with a whisk. She pours the ingredients into a pan and bakes them. When the cake is baked, she frosts the cake. Which part of making a cake is a chemical change?

• A. Mixing ingredients with a whisk, because the mixed ingredients form a thick liquid.
• B. Adding eggs because the eggs change shape when they are cracked.
• C. Baking the mixed ingredients because the ingredients change into a different substance.
• D. Putting frosting on the baked cake because frosting changes how the cake looks.

Which of the following best explains what happens when a popsicle melts?

• A. It is a physical change because a new substance was made.
• B. It is a physical change because it can be easily reversed.
• C. It is a chemical change because the properties of the popsicle changed.
• D. It was a chemical change because it cannot be easily reversed.

What is the difference between a chemical change and a physical change?

• A. A substance stays the same In a chemical change, but a new substance is formed in a physical change.
• B. After a physical change, a substance cannot change back, but it is easy to reverse a chemical change.
• C. A physical change includes changing state from solid to liquid, but changing from liquid to gas is a chemical change.
• D. A new substance is formed in a chemical change, but the substance stays the same in a physical change.

Some students added sugar to three cups of water. The water in each cup was a different temperature. They stirred each cup of water after adding the sugar. Their data is shown in the table. Which of these BEST explains why the sugar dissolved at the rate it did?

• A. Sugar dissolves faster in water that is warmer.
• B. Sugar dissolves faster at room temperature.
• C. Sugar dissolves faster in smaller amounts.
• D. Sugar dissolves more quickly in water that is stirred.

Which of the following actions will increase the rate of dissolution of a solid solute into an aqueous solution?

• A. Stirring with a spoon
• B. Freezing the solute
• C. Decreasing the temperature
• D. Continuously adding more solute