Conservation Balancing

If a chemical reaction such as photosynthesis begins with 6 atoms of carbon (C), how many atoms of carbon (C) should be in the products?

• 12 atoms of carbon (C)
• 6 atoms of carbon (C)
• 3 atoms of carbon (C)
• 2 atoms of carbon (C)

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which best explains why the total mass of the product(s) would be less than the total weight of the reactant(s) after a chemical reaction?

• A physical change occurred.
• Atoms involved in the reaction lost mass.
• Precipitates were created in the new solution.
• Gases were released to the atmosphere.

Tags

NGSS.MS-PS1-5

How does a balanced chemical equation satisfy the Law of Conservation of Mass?

• During a chemical reaction, the total amount of matter stays the same.
• During a chemical reaction, matter is destroyed.
• During a chemical reaction, one or more new substances are formed.
• During a chemical reaction, the total number of atoms increases.

Tags

NGSS.MS-PS1-5

Which is best represented by the equation?
2Mg + O₂ → 2MgO

• Law of Conservation of Energy
• Law of Conservation of Mass
• Law of Superposition

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

What is the importance of a closed container in a chemical reaction?

• to observe the mass before and after the reaction occurs
• to keep any materials from interfering with the reaction
• to observe the loss of mass after the reaction occurs

Tags

NGSS.MS-PS1-5

Which best represents a balanced equation?

• 120 grams of carbon plus 20 grams of oxygen → 200 grams of carbondioxide
• 120 grams of carbon plus 50 grams of oxygen → 200 grams of carbondioxide
• 120 grams of carbon plus 80 grams of oxygen → 200 grams of carbondioxide

Tags

NGSS.MS-PS1-5

What coefficient for O₂ demonstrates the law of conservation of mass?
CH₄(g) + __O₂(g) → CO₂(g) + 2H₂O(g)

• 1
• 2
• 3
• 4

Tags

NGSS.MS-PS1-5

Which equation is balanced according to the Law of Conservation of Mass?

• NaCl + Mg →
   MgCl₂ + Na
• 2NaCl + Mg → MgCl₂ + Na
• 2NaCl + Mg →
  MgCl₂ + 2Na

Tags

NGSS.MS-PS1-5