PS8.1.3/PS8.1.5 Review

In the chemical formula H₂O, what does the subscript "2" indicate?

• a) There are 2 oxygen atoms.
  

• b) There are 2 hydrogen atoms.

• c) There are 2 water molecules.

• d) There are 2 water atoms.

Tags

NGSS.MS-PS1-1

Which of the following is the correct way to balance the equation below?

H₂ + O₂ → H₂O

• a) H₂ + O₂ → H₂O
  

• b) 2H₂ + O₂ → 2H₂O
  

• c) 2H₂ + 2O₂ → H₂O
  

• d) H₂ + 2O₂ → 2H₂O

Tags

NGSS.MS-PS1-5

How many oxygen (O) atoms are there in the compound CaCO₃?

• a) 1
  

• b) 2
  

• c) 3
  

• d) 4

Tags

NGSS.MS-PS1-1

What is the total number of atoms in the molecule C₂H₆?

• a) 2
  

• b) 6
  

• c) 8
  

• d) 12

Tags

NGSS.MS-PS1-1

Which of the following equations is balanced?

• a) C + O₂ → CO
  

• b) 2Na + Cl₂ → 2NaCl
  

• c) CH₄ + O₂ → CO₂ + 2H₂O
  

• d) H₂ + O₂ → H₂O

Tags

NGSS.MS-PS1-5

In a chemical reaction, what does a coefficient in front of a molecule indicate?

• a) How many atoms are in the molecule
  

• b) How many molecules are present
  

• c) The number of subscripts
  

• d) The number of bonds in the molecule

Tags

NGSS.HS-PS1-7

The law of conservation of mass states that:

• a) Mass can be created and destroyed in chemical reactions.
  

• b) The total mass before and after a chemical reaction remains the same.
  

• c) Atoms are destroyed during a chemical reaction.
  

• d) Mass is transferred between reactants and products.

Tags

NGSS.MS-PS1-5

If you start a reaction with 12 grams of reactants, how much product should you expect according to the law of conservation of mass?

• a) Less than 12 grams
  

• b) 12 grams
  

• c) More than 12 grams
  

• d) Depends on the type of reaction

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

In a closed system, which of the following statements is true during a chemical reaction?

• a) Mass can escape from the system.
  

• b) Matter can enter or leave the system.
  

• c) The total mass within the system remains the same.
  

• d) Energy is created within the system.

Tags

NGSS.MS-PS1-5

Which scenario describes an open system?

• a) A sealed jar where a reaction occurs without anything escaping.
  

• b) A reaction that takes place in a tied balloon.
  

• c) A reaction that occurs in an uncovered beaker.
  

• d) A reaction that occurs inside a pressurized container.

Tags

NGSS.MS-PS1-2