Chemical Reactions

A student observes some sugar as it is heated and burns. The student concludes that a chemical reaction has occurred. Which of the following observations about the burning sugar provides evidence of a chemical reaction? (8.5E)

• Heat is added to the sugar crystals.

• The sugar melts and becomes a liquid.

• The temperature of the sugar increases.

• Gas is produced as the sugar turns black.

Tags

NGSS.MS-PS1-2

Which of the following could be the chemical formula for sulfuric acid (shown in the picture)? (8.5D)

• HSO

• HSO₄

• H₂SO₄

• HS₂O₄

Tags

NGSS.MS-PS1-1

All of the following chemical equations are balanced EXCEPT -- (8.5F)

• a

• b

• c

• d

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-5

Based on the reaction shown, which statement best SUPPORTS the Law of Conservation of Mass? (8.5F)

Zn + 2HCl -----> ZnCl₂ + H₂

• There are more chlorine atoms in the reactant.

• There are more hydrogen atoms in the product.

• The number of chlorine atoms is unequal in the reactants and products.

• The number of reactant atoms is equal to the number of product atoms.

Tags

NGSS.MS-PS1-5

How many elements are found in 2H₂SO₄? (6.5C)

• 2

• 3

• 4

• 5

Tags

NGSS.MS-PS1-1

Which two compounds contain the same total number of atoms? (8.5D)

• a

• b

• c

• d

Tags

NGSS.MS-PS1-1

Chemicals on the left of an equation that react are called -- (8.5F)

• reactants

• products

• coefficients

• subscripts

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Chemicals on the right of an equation that are produced are called -- (8.5F)

• reactants

• products

• coefficients

• subscripts

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which of these is NOT a sign that a chemical change has occurred? 

• A loss of transparency 
• An unexpected color change
• A temperature change
• The formation of a precipitate

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4

In a ___________change, a substance changes into a different substance.

• Physical
• Chemical

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5