Chemical Reactions and Equations

What happens in a chemical reaction?

• Bonds between atoms break and/or are formed

• New atoms are created and/or removed

• Protons move from one atom to another

• Electrons change into protons

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

How are chemical bonds formed?

• Atoms duplicate themselves

• Electrons move from one atom to another

• The number of protons and electrons in an element is changed

• Through changes in an atom's nucleus

Tags

NGSS.MS-PS1-5

Which of the following would indicate that a chemical reaction has occurred?

• A new element has been created

• A different substance has formed

• The total mass has either increased OR decreased

• The total number of elements has either increased OR decreased

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

These are all models of the same molecule. What would this molecule look like in a chemical/molecular formula?

• CH

• C4H

• CH₄

• 4CH

Tags

NGSS.MS-PS1-1

Which would indicate a chemical equation is balanced?

• If the number of atoms in the reactants is the same as the number of atoms in the products

• If the atoms have ionic OR covalent bonds

• If the atoms have full valence shells

• If the total energy has remained the same

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

BEFORE the equation is balanced, how many Hydrogen atoms are present on the reactant side?

• 6

• 2

• 12

• 8

Tags

NGSS.HS-PS1-7

Why does the number of Carbon atoms need to be the same on both sides of the reaction?

• In a chemical reaction, no new atoms can be made

• Because the number of Oxygen atoms must be balanced with the number of Carbon and Hydrogen atoms

• Because the coefficients and the subscripts need to be equal

• It does NOT need to be the same

Tags

NGSS.MS-PS1-5

What coefficient should go in the last blank space in order for the equation to be balanced?

• 1

• 2

• 3

• 4

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

How many sulfur atoms are present in this molecule?

• 4

• 3

• 12

• 1

Tags

NGSS.MS-PS1-1

In the molecule below, which of the following choices is a subscript? (Select all that apply)

• 3

• 2

• 4

• SO

Tags

NGSS.MS-PS1-1