Law of Conservation of Mass

How many elements does PbNO₃ have?

• 2
• 3
• 4
• 5

Tags

NGSS.MS-PS1-1

How many nitrogen atoms does NH₃ have?

• 1
• 2
• 3
• 4

Tags

NGSS.MS-PS1-1

A chemical equation tells us 

• the reactants and the products.
• the elements that make up the reactants and the products.
• the number of atoms that make up the reactants and the products.
• All of the above.

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-5

What is the reactant in the following equation?
2NaHCO₃  -> Na₂CO₃  +  CO₂  + H₂O

• NaHCO₃
• Na₂CO₃
• CO₂
• H₂O

Which of the following describes the law of conservation of mass?

• In a reaction, atoms are created or destroyed.
• In a reaction, atoms are not lost or made.
• In a reaction, the mass of the product may be more or less than the reactants.
• In a reaction, mass never stays the same.

Tags

NGSS.MS-PS1-5

For the equation:
2H₂ +  O₂ --> 2H₂O
How much H₂O will be produced using only one O₂?

• 1/2
• 1
• 2
• 4

For the equation:
2H₂ +  O₂ --> 2H₂O
How much H₂O will be produced if we react 4g of H₂ and 32g of O₂?

• 4g
• 32g
• 36g
• 28g

Which  of the following is a balanced equation?

• Na   +   Cl₂   -->  NaCl
• H₂  +  O₂  --> H₂O
• Ca   +   Br  -->  CaBr₂
• Na   +  F  -->  NaF

What will happen to the mass of the product if I double the mass of the reactants?

• It will decrease by half.
• It will increase by half.
• It will double in amount.
• The mass remains the same.

Tags

NGSS.MS-PS1-5

Balance the following equation:
__N₂  +  __H₂  -->  __NH₃

• N₂  +  3H₂  --> 2NH₃
• 2N₂  +  3H₂  --> NH₃
• 3N₂  +  2H₂  --> 2NH₃
• N₂  +  H₂  --> NH₃