Science extra credit

Which of the following represent a chemical change?

• Melting of ice
• Rusting of iron, burning of wood, and digestion of food represent chemical changes.
• Dissolving sugar in water
• Boiling of water

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

Which of the following represents a balanced chemical equation?

• H2 + O2 -> 2H2O2
• 2H2 + O2 -> 2H2O
• 2H2 + O2 -> H2O2
• H2 + O2 -> H2O

Tags

NGSS.MS-PS1-5

How do you know that a chemical change has occurred?

• A chemical change is indicated by a change in temperature only.
• A chemical change has occurred if there are observable changes such as color change, gas production, or formation of a precipitate.
• A chemical change can only be identified by smell.
• A chemical change occurs when a substance is mixed with water.

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

How do you know that a physical change has occurred?

• A physical change has occurred when there is a change in state or appearance without a change in chemical composition.
• A physical change results in the formation of new substances.
• A physical change can only be observed through chemical reactions.
• A physical change involves a change in chemical composition.

Tags

NGSS.MS-PS1-4

Which of the following represents a physical change?

• Boiling water
• Dissolving sugar in water
• Freezing water
• Melting ice cream

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

what is the definition of an unbalanced chemical equation?

• An unbalanced chemical equation is a type of chemical reaction that occurs spontaneously.
• An unbalanced chemical equation has equal numbers of atoms on both sides.
• An unbalanced chemical equation is a representation of a reaction that only shows products.
• An unbalanced chemical equation is a chemical equation that does not have equal numbers of each type of atom on both sides.

Tags

NGSS.MS-PS1-5

Is the following statement true or false?

An example of a physical change is the tearing of paper.

• false
• true

What is a subscript in a chemical equation?

• A subscript indicates the molecular weight of a compound.
• A subscript represents the charge of an ion.
• A subscript indicates the number of atoms of an element in a molecule.
• A subscript shows the state of matter of a substance.

Which of the following can be represented by a chemical change?

• Sugar dissolving in water
• Rust forming on iron
• Ice melting
• Water boiling

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

True of false

Water boiling is a chemical change

• True

• False

Tags

NGSS.MS-PS1-4