Science Competency

Which of the following is a chemical reaction?

• Sodium and chlorine atoms bond to form salt molecules.

• Ice melts to form water.

• Carbon dioxide freezes to form dry ice.

• Salt and water mix to form salt water

Tags

NGSS.MS-PS1-2

2H₂ + O₂ -> 2H₂O

In the equation shown, what are the reactants?

• Hydrogen atoms

• Hydrogen and oxygen molecules

• Water molecules

• Ice crystals

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-2

Sulfuric acid is made of two hydrogen atoms (H), one sulfur atom (S), and four oxygen atoms (O). What is its molecular formula?

• 2H₄SO

• H₄S₂O

• H₂SO₄

• H₂S₂O₄

Tags

NGSS.MS-PS1-1

What is the best synonym for the word "stoichiometry?"

• combining atoms

• balancing chemical equations

• discovering new chemicals

• breaking the chemical bonds that hold molecules together

Tags

NGSS.HS-PS1-7

The chemical symbol "Ni" most likely represents:

• Carbon

• Antimony

• Lead

• Nickel

How do the products of chemical reactions compare to their reactants?

• The products usually weigh more than the reactants.

• The products often have completely different properties than the reactants.

• The products usually have more atoms than the reactants.

• The products are usually more toxic than the reactants.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

H_{2 +} O₂ -> H₂O

What's the problem with the chemical equation shown?

• There's a missing hydrogen in the reactants.

• There's a missing oxygen in the product.

• There's an additional oxygen in the product.

• There's an additional hydrogen in the reactants.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

What's the easiest way to balance a chemical equation?

• Trial and error

• Using the periodic table

• Complex algebra

• Calculus

Tags

NGSS.MS-PS1-5

__ + PO₄ -> H₃PO₄

_{Which reactant is missing from the equation shown?}

• One hydrogen atom

• One phosphorus atom

• Three hydrogen atoms

• One oxygen atom

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-5

2Na + S₂O₃ -> _________________

What is the product of the equation shown?

• NaS₂O₃

• NaS₄O₃

• Na₂S₂O₅

• Na₂S₂O₃

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-2

NGSS.MS-PS1-5