Characteristics of Chemical Reactions

Match the following

Groups:

(a) Chemical Reaction

,

(b) Physical Change

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Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4

Hydrogen and oxygen react to form water. At an atomic level, how do we know that a chemical reaction has occurred?

• Hydrogen molecules are negative, and oxygen positive

• For every oxygen atom, two hydrogen atoms are needed.

• The hydrogen and oxygen atoms regroup into a new molecule.

• Oxygen atoms are much larger than hydrogen atoms.

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NGSS.MS-PS1-2

NGSS.MS-PS1-5

A chemical reaction occurs that involves combining 1 atom of zinc with 2 atoms hydrogen and 2 atoms of chlorine. After the reaction, how many atoms of each element will there be?

• 1 zinc, 2 hydrogen, 2 chlorine

• 2 zinc, 2 hydrogen, 2 chlorine

• 2 zinc, 1 hydrogen, 2 chlorine

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NGSS.MS-PS1-2

NGSS.MS-PS1-1

NGSS.MS-PS1-5

Which of the following is the best description of the results of a chemical reaction?

• A new substance with different properties is formed.

• The substance seems to disappear after dissolving in water.

• The substance changes from liquid to solid at a low temperature.

• The reaction can be reversed to get back the original substance.

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NGSS.MS-PS1-2

During a chemical reaction, substances (called reactants) are combined to form new substances (called products). Which of the following accurately describes the reactants and the products of a chemical reaction?

• The products contain a different number of atoms than the reactants but have the same properties.

• The number of atoms and the properties are the same in the reactants and the products.

• The products contain the same number of atoms as the reactants but have different properties.

• The number of atoms and the properties are different in the reactants and the products.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Four students performed four different investigations by combining different substances. Their results are shown in the table to the left. In ​ ​ (a)   , a chemical reaction took place. The other experiments ​ (b)   result in a chemical reaction.

• Experiment 1
• Experiment 2
• Experiment 3
• Experiment 4
• did not
• did

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NGSS.MS-PS1-2

Which observations are evidence that a chemical reaction took place?

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NGSS.MS-PS1-2

The basic unit of an element like chlorine is an ​ (a)   , whereas the basic unit of a compound like sodium chloride is a ​ (b)   .

• atom
• molecule
• compound
• crystal

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NGSS.MS-PS1-1

What is the arrow pointing to?

• Atom

• Molecule

• Chemical Bond

• Element

Tags

NGSS.MS-PS1-1

What is circled in the picture?

• Atom

• Molecule

• Chemical Bond

• Element

Tags

NGSS.MS-PS1-1