Practice Test: Unit 2 6-`15

What Makes PH Paper Change Color? Describe how a model can be used to explain what happened in the activity. Choose all that apply.

• Some of the liquid becomes a gas and evaporates into the air.

• The liquid in the container became a solid.

• The paper changes a red color.

• The particles of ammonia in the air caused the indicator paper to change a blue color.

What is a model of the paper over a test tube unable to show? Choose all that apply.

• That the paper changed color.

• How the paper changes color.

• All of the movement of the particles in the test tube.

• That the ammonia changed into a gas.

What makes the paper change color?

• The paper changes color in the light.

• The paper changes color because some of the liquid evaporates and becomes a gas. The gas travels to the paper and causes it to change color.

• The paper changes color because some of the liquid goes up the sides of the container and reaches the paper. This causes it to change color.

• The paper does not actually change color. The gas modifies how we see the paper.

Do you know an adult who drinks coffee, tea, or soda pop? Think about that person and picture them in your mind. Choose a description that helps that person understand how they can smell their favorite beverage even though it is a liquid. Choose all that apply.

• There are particles in your coffee that get into the air and travel to your nose.

• There are particles in your coffee that stay in the coffee so you can smell them if you get close.

• Your nose is a detector and detects the particles when they get into the air.

• You see the coffee and it makes you smell it.

What evidence do you have that gases are different?

• We can see that they are different.

• They have different names.

• They behave differently when they give off light.

• Some gases move faster or slower than others.

Why do the different gases give off different colors of light?

• The gases are made up of different particles.

• Light is absorbed by the gas.

• The gas makes the light be different colors.

• The speed of the movement of gases determines which color of light the gas gives off.

What are the most important things a new student should know about properties in order to catch up with your class. Choose all that apply.

• Properties can be different for different sizes of the same substance.

• Properties are always the same for a substance. 

• Properties of different substances can be all the same.

• Properties help tell substances apart.

Gold is an element because

•  it has 1,077 sextillion atoms in a small block. 

• it is a metal. 

• it is made up of only gold atoms.

Calcium and nitrogen are both elements. What makes one element different from another element?

• They are different colors and sizes.

• They have different properties and are found in different places.

• They have different properties and are made of different types of atoms.

• They are made of different types of atoms and have the same properties.

The black spheres represent nitrogen atoms, the white spheres represent hydrogen atoms. Based on the model, what is the atomic composition of hydrazine?

• 1 atom of nitrogen and 1 atom of hydrogen.

• 4 atoms of nitrogen and 2 atoms of hydrogen.

• 2 atoms of nitrogen and 2 atoms of hydrogen.

• 2 atoms of nitrogen and 4 atoms of hydrogen.