1.

Question

(02.01 LC)

The image below shows particles tightly packed together. (5 points)

A square is shown with the title State of Matter. An array of circles arranged neatly in rows and columns is shown. Tiny single arcs are shown near some circles near the outer edge of the array

Which state of matter is most likely represented in the image?

Gas

Solid

Liquid

Plasma
2.
(02.01 LC)

Dan wrote the following phrase to describe the movement of particles in a state of matter.

"Small pea seeds move around each other but do not bounce off."

Which state of matter did Dan most likely describe? (5 points)

Gas

Plasma

Liquid

Solid
3.
(02.01 MC)

Polly did an experiment with marbles in a glass bowl to show the movement of particles in solids, liquids, and gases. The experimental set-up is shown below: (5 points)

A glass bowl is shown with four marbles inside it.

What should Polly do to represent the particles of a solid?

Pack the bowl with marbles and then tap it gently.

Add two more marbles to the bowl and then shake it slowly.

Take out two marbles from the bowl and then shake it vigorously.

Add water to the bowl so that the marbles start sliding past one another.
4.
(02.02 LC)

Which of the following represents a chemical change? (5 points)

Bending a wire

Freezing of water

Fireworks exploding

Melting of a wax candle
5.
(02.02 LC)

If a physical change has taken place, which of these is most likely true? (5 points)

A permanent change has taken place.

The changed substance retains its unique properties.

Atoms rearrange to form a new substance.

The molecular composition of a substance changes.
6.
(02.02 MC)

A plant uses carbon dioxide and water to form food and oxygen. Why is this a chemical change? (5 points)

The mass of the plant increases greatly.

The properties of water and food are same.

The plant increases in height as food is produced.

The properties of carbon dioxide and oxygen are different.
7.
(02.03 LC)

To make lemonade Erica dissolved 30 g of sugar in a certain amount of water. By what amount is the mass of water likely to increase after the sugar dissolves? (5 points)

0 g

10 g

15 g

30 g
8.
(02.03 MC)

In a chemical interaction 10 g of hydrogen chloride is added to 20 g of zinc to form 24 g of zinc chloride and a certain amount of hydrogen gas. What mass of hydrogen gas is expected to be formed? (5 points)

6 g

14 g

34 g

54 g
9.
(02.03 MC)

Is mass conserved when 200 g of water undergoes a physical change? Use complete sentences to support your answer by explaining how this can be demonstrated. (10 points)

10.
(02.04 LC)

Which of the following most likely happens when the temperature of a chemical reaction is increased? (5 points)

Molecules speed up

Molecules stop reacting

Reaction rate decreases

Chemical reaction stops
11.
(02.04 LC)

Given two temperatures, 39 °F and 51 °F, which of the following correctly compares the number of chances for particles to bounce off each other during a chemical reaction? (5 points)

Same at both

Lower at 39 °F

Lower at 51 °F

Does not depend on temperature
12.
(02.04 MC)

During an investigation, similar effervescent tablets were dropped into a beaker containing cold water and a beaker containing tap water. The table below shows an incomplete record of the investigation.

Investigation Results
Beaker Time Taken for the Tablet to Dissolve
(seconds)
Cold Water (50 ml) 68
Tap Water (50 ml) ?

Which statement best explains the time taken for the tablet to dissolve in tap water? (5 points)

Less than 68 seconds as the rate of reaction is higher for cold water

Less than 68 seconds as the rate of reaction is higher for tap water

More than 68 seconds as the rate of reaction is lower for cold water

More than 68 seconds as the rate of reaction is lower for tap water
13.
(02.05 MC)

The graph below compares the volume occupied by 100 g of liquid water and 100 g of water vapor. (5 points)

A bar graph is shown with the title, Volume Occupied. The y axis title is, Volume. The x axis title is, Substance. There are two markings on the x axis. One is marked X and the other is marked Y. The bar above X is far higher than the bar above Y.

Which statement best describes the two substances?

Particles are farther apart in liquids so substance Y is liquid water.

Particles are closer together in liquids so substance X is liquid water.

Particles are closer together in gases so substance Y is water vapor.

Particles are farther apart in gases so substance X is water vapor.
14.
(02.05 HC)

During an investigation, a scientist heated 123.6 g of copper carbonate till it decomposed to form a black residue. The total mass of the black residue formed was 79.6 g. Does the law of conservation of mass hold true in this case? Use complete sentences to justify your answer based on numerical calculations. (10 points)

Answer 1

Here are answers with explanations for each question:

1. Solid
   The tightly packed particles in rows and columns suggest a solid state of matter, where particles have fixed positions and vibrate in place.

2. Liquid
   The description of "small pea seeds move around each other but do not bounce off" indicates a liquid state, where particles are close together but can flow and slide past one another.

3. Pack the bowl with marbles and then tap it gently.
   This action simulates the closely packed arrangement of particles in a solid, which can only vibrate in fixed positions.

4. Fireworks exploding
   This represents a chemical change, as new substances are created during the explosion, and energy is released.

5. The changed substance retains its unique properties.
   In a physical change, the composition of the substance remains the same, meaning its properties do not change.

6. The properties of carbon dioxide and oxygen are different.
   This indicates a chemical change, where the reactants (carbon dioxide and water) form new products (food and oxygen) with different properties.

7. 30 g
   The mass of water would increase by the mass of the sugar dissolved, so if 30 g of sugar is added, the mass of the solution increases by 30 g.

8. 14 g
   According to the law of conservation of mass: Total mass of reactants = Total mass of products. Thus, 10 g of hydrochloric acid + 20 g of zinc = 24 g of zinc chloride + mass of hydrogen. The mass of hydrogen gas is 10 g + 20 g - 24 g = 6 g.

9. Mass is conserved when 200 g of water undergoes a physical change.
   Mass conservation means that the total mass remains constant. For example, when ice melts into water, the mass remains 200 g before and after the change, which can be demonstrated by weighing the container before and after the melting process.

10. Molecules speed up
    Increasing the temperature typically increases the kinetic energy of molecules, leading to faster movement and increased reaction rates.

11. Lower at 39 °F
    Higher temperatures generally provide more energy to the particles (molecules), increasing the chances of them bouncing off each other and reacting.

12. Less than 68 seconds as the rate of reaction is higher for tap water
    Tap water is typically warmer than cold water, which would speed up the dissolving process of the tablet.

13. Particles are farther apart in gases so substance X is water vapor.
    The higher bar represents a greater volume associated with water vapor (gas) compared to liquid water, indicating that gas particles are more spread out.

14. The law of conservation of mass does not hold true in this case.
    Initially, 123.6 g of copper carbonate decomposed into a residue weighing 79.6 g. If we calculate the missing mass: 123.6 g - 79.6 g = 44 g. This loss of mass suggests that gases (likely carbon dioxide) escaped during the process, violating the conservation of mass principle.