Chemical Reaction Changes

What is most likely true about the yellow solid?

• A. It is a new substance with different properties.

• B. It is solid potassium iodide.

• C. It was secretly added to the test tube by the scientist.

• D. It is solid lead nitrate.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which is the correct conclusion based on the data?

• A. A chemical reaction did not occur because physical properties, such as boiling point, do not change.

• B. A chemical reaction took place because the same elements were present before and after the change occurred.

• C. A chemical reaction occurred because the chemicals that were combined have different boiling points than the chemicals produced.

• D. A chemical reaction did not occur because both zinc and zinc chloride are known to be solids at room temperature.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

A teacher has two cubes of sugar that are both the same size and shape. He adds cube A to a beaker filled with 100 mL of water, and the cube completely dissolves in the water. He then places cube B on a glass dish over a flame. He keeps the dish over the flame until cube B has turned completely black. Once cube B has cooled off, he adds it to another beaker filled with 100 mL of water. Cube B does not dissolve in water.

What does this demonstration indicate?

• Dissolving sugar in water results in a chemical reaction.

• Sugar is a mixture that can be separated by burning it.

• Burning sugar results in a chemical reaction.

• Sugar is a mixture that can be separated by dissolving it in water.

Tags

NGSS.MS-PS1-2

Which statement describes a change that occurs during a chemical reaction?

• Atoms in the original substances are changed into different atoms to make new substances.

• The atoms in a substance start to move faster until they are no longer touching each other.

• The atoms in a substance change their properties so they can become a new substance.

• Atoms in the original substances are arranged in a different way to make new substances.

Tags

NGSS.MS-PS1-2

Four preparations involving table sugar (sucrose) are described below. Analyze the sugar preparation processes and the end products. Sugar Water: Sugar is added to water, and the water is stirred until the sugar is no longer visible. Sugar Floss: Sugar is melted and blown with a fan to make thin threads of solid sugar. Sugar Caramel: Pure sugar is melted and cooked until it changes color and becomes a thick, sticky liquid. Rock Sugar: A highly concentrated solution of sugar water is prepared, large sugar crystals are allowed to form slowly, and then dye is added. Which of the following is evidence that a chemical reaction has taken place in one of the processes?

• A. The slow growth of giant sugar crystals from a highly concentrated sugar-water solution and added dye

• B. The color change that takes place after heat melts and begins to decompose the sugar

• C. The dissolution of solid sugar in water to form a thin, colorless, odorless liquid

• D. The melting and re-solidification of sugar into threads, which are different from sugar’s natural cube-shaped crystals

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Jayne's science teacher mixed a clear liquid with a blue liquid in a beaker. After a few minutes there was a white solid at the bottom of the beaker. What is most likely true about the white solid?

• It was secretly added to the beaker by the teacher.

• It will dissolve in the solution when stirred.

• It is a new substance with different properties.

• It will dissolve in water to form a blue solution.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Calcium carbonate (CaCO3) is heated and decomposes to form calcium oxide (CaO) and carbon dioxide (CO2). Which statement is true about the difference between calcium carbonate and calcium oxide?

• Calcium oxide has the same physical properties and the same chemical properties.

• Calcium oxide has different physical properties and different chemical properties.

• Calcium oxide has the same physical properties and different chemical properties.

• Calcium oxide has different physical properties and the same chemical properties.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-1

Which observations indicate that a chemical change occurs when she mixes the two chemicals together?

• The chemicals change color from colorless to purple.

• A brown solid forms in the bottom of the beaker.

• A yellow gas forms.

• The temperature of the chemicals rises 15°C.

Tags

NGSS.MS-PS1-2

Twenty-four grams of magnesium metal reacts with sixteen grams of oxygen gas to form magnesium oxide. According to the law of conservation of mass, how much magnesium oxide will there be after the chemical change is complete?

• 16 g

• 30 g

• 40 g

• 24 g

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

What is true about the mass of the nitrogen atoms in this reaction?

• The mass of the nitrogen atoms increases in the reactants and decreases in the products.

• The mass of the nitrogen atoms decreases in the reactants and increases in the products.

• The mass of the nitrogen atoms in the reactants is equal to the mass of the nitrogen atoms in the products.

• The mass of the nitrogen atoms in the reactants is greater than the mass of the nitrogen atoms in the products.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5