Chemical Reactions and Equations

What is the coefficient of the oxygen molecule in the elephant toothpaste equation?

2 H₂O₂ -> 2 H₂O + O₂

• 0

• 1

• 2

• 4

What do you call the substances on the left side of a chemical equation?

• yield
• products
• reactants
• compounds

Tags

NGSS.MS-PS1-1

Which is the correct atom count for the reactant side of the chemical equation?
CH₄ + 2 O₂ -> CO₂ + 2 H2O

• C=4
  H=4
  O=4
• C=1
  H=4
  O=2
• C=1
  H=4
  O=2
• C=1
  H=4
  O=4

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-5

Which is NOT an indicator of a chemical change?

• temperature change
• formation of a precipitate
• shape change
• production of light

Tags

NGSS.MS-PS1-2

Which example shows evidence of a chemical change?

• a glass bowl shatters when it hits the floor
• lemonade powder is mixed in water
• an apple is cut for a snack
• milk sours in the refrigerator

Tags

NGSS.MS-PS1-2

A coefficient tells you...

• the # of atoms in the entire equation
• the # of elements in the equation
• the # atoms of the element it sits behind
• the # of molecules of that substance

Tags

NGSS.HS-PS1-7

A subscript tells you...

• the # of atoms in the entire equation
• the # of elements in the equation
• the # atoms of the element it sits behind
• the # of compounds present

Tags

NGSS.MS-PS1-1

When two substances were combined, bubbles were produced and the temperature dropped.  This most likely means that:

• a chemical reaction took place
• the two substances had low boiling points
• one substance dissolved in the other
• the two substances are non-reactive

Tags

NGSS.MS-PS1-2

Before a chemical reaction, the total mass of two reactants is measured to be 40 grams.  After the reaction, what should be the total mass of the products?

• 0 grams
• 20 grams
• 40 grams
• 80 grams

Tags

NGSS.MS-PS1-5

Copper chloride and aluminum react to produce aluminum chloride and copper.  Which of the following is the correctly balanced chemical equation for this reaction?

• CuCl₂ + Al -> AlCl₃ + Cu
• 3CuCl₂ + Al -> AlCl₃ + 2Cu
• 3CuCl₂ + 2Al -> 2AlCl₃ + 3Cu
• CuCl₂ + 3Al -> AlCl₃ + 2Cu

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5