Unit 2 Test Review EOY

Ben wants to model how the motion of particles changes with temperature. He considers water in an iron pot. Ben draws a model to show how the water particles and iron particles move at room temperature. Then he draws a second model to show how the water particles and iron particles move as the pot of water is heated. Based on this evidence, how should Ben’s second model differ from the first?

• The water particles should vibrate faster, and the iron particles should not move.

• Both the water particles and the iron particles should slide past each other faster.

• The water particles should slide past each other faster, and the iron particles should vibrate faster

• The water particles should move freely in all directions, and the iron particles should slide past each other faster

Answer explanation

As temperature increases, water particles gain energy and slide past each other faster, while iron particles vibrate more due to increased thermal energy. Thus, the correct choice is that water particles slide faster and iron particles vibrate faster.

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NGSS.MS-PS1-4

Which claim about the carbon atoms that make up a diamond can be supported by evidence?

• They can slip past one another slowly

• They are always vibrating in place

• They vibrate only when they are heated

• They are locked in place and do not move at all.

Answer explanation

In a diamond, carbon atoms are arranged in a rigid structure, but they are always vibrating in place due to thermal energy. This constant vibration occurs even at low temperatures, supporting the claim that they are always vibrating.

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NGSS.MS-PS3-5

Inez is making a model of a sugar crystal. She wants her model to show how the sugar molecules move in the crystal. She is using plastic foam balls to represent the sugar molecules. How should she put the plastic foam balls together to make her model?

• glue them together

• join them like beads on a string

• connect them with stiff springs

• place a few of them in a plastic bag

Answer explanation

Connecting the plastic foam balls with stiff springs best represents the movement of sugar molecules in a crystal, as it allows for flexibility and movement, mimicking the vibrational motion of molecules in a solid structure.

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NGSS.MS-PS1-1

Which model (or models) above could be Tyson’s drawing of particles in a LIQUID?

• model 1

• model 2

• model 3

Answer explanation

Model 1 accurately represents particles in a liquid, showing them close together but still able to move past one another, which is characteristic of liquid states. The other models do not depict this behavior.

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NGSS.MS-PS1-4

Raul and Bonnie are trying to classify several objects that they found during a field trip to the beach. They collected a sample of seawater, a piece of driftwood, and several smooth pebbles. What property does the driftwood share with the pebbles that it does not share with the water?

• A. Its particles move freely in all directions.

• B. Its particles vibrate, but are locked in place.

• C. Its volume does not depend on its container.

• D. Its volume will change in different containers.

Answer explanation

The driftwood and pebbles are solids, where their particles vibrate but are locked in place, unlike water, which is a liquid with freely moving particles. Thus, B is the correct choice.

Carbon has an atomic number of 6. Based on this evidence, what can you claim about carbon

• the number of protons in a carbon atom

• the average atomic mass of a carbon atom

• the group number of carbon

• the period number of carbon

Answer explanation

Carbon's atomic number of 6 indicates it has 6 protons. This is a fundamental property of an element, making 'the number of protons in a carbon atom' the correct choice.

Based on its location in the periodic table, what statement best describes the element Ca?

• It breaks easily like glass.

• It is shiny and can be bent and shaped.

• It doesn’t conduct electricity.

• It is definitely not a metal.

Answer explanation

Calcium (Ca) is an alkaline earth metal, which means it is shiny and malleable, allowing it to be bent and shaped. The other options do not accurately describe its metallic properties.

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NGSS.MS-PS1-1

Any atom that has 13 protons is an aluminum atom. Which statement best describes what would happen if a proton were added to an aluminum atom?

• The atom would lose electrons.

• The atom would have a negative charge.

• The atom would no longer be aluminum.

• The atom would have a smaller atomic number.

Answer explanation

Adding a proton to an aluminum atom (which has 13 protons) increases its proton count to 14, changing its identity to silicon. Therefore, the correct statement is that the atom would no longer be aluminum.

What do elements in the same group on the periodic table have in common?

• They have similar chemical symbols.

• They have the same atomic number.

• They have similar chemical properties.

• They have the same average atomic mass.

Answer explanation

Elements in the same group share similar chemical properties due to their similar electron configurations, which influence their reactivity and bonding behavior.

Consider a wooden chair and a balloon. Which claim describes what these two objects always have in common?

• Both are made of atoms.

• Both have the same mass number.

Answer explanation

Both the wooden chair and the balloon are composed of atoms, which are the basic building blocks of matter. This is a fundamental property they share, unlike mass number, which varies between different materials.

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NGSS.MS-PS1-1