Law of conservation of mass

What is the Law of Conservation of mass?

• Mass is created in a chemical reaction
• Mass is created in a physical change
• New chemicals formed from a chemical reaction have a larger overall mass than the original reactants
• Mass is never created or destroyed

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

In a reaction A + B ----> C,  reactant A has 5g and product  C has 9g. How many grams does reactant B should have? 

• 4g
• 5g
• 9g
• 14g

Tags

NGSS.MS-PS1-5

The number in front of a compound or element is a 

• Subscript
• Coefficient
• Superscript
• Charge

The number to the lower side of an element is a 

• Subscript
• Superscript
• Coefficient
• Charge

Tags

NGSS.MS-PS1-1

Matter can not be created nor destroyed: it can only be

• Destroyed a little bit
• Invisible
• Transformed, changed
• None of the above

Tags

NGSS.MS-PS1-5

How many nitrogen atoms does NH₃ have?

• 1
• 2
• 3
• 4

Tags

NGSS.MS-PS1-1

How many oxygen atoms are in this chemical formula?

• 6 oxygen atoms
• 2 oxygen atoms
• 3 oxygen atoms
• 4 oxygen atoms

Tags

NGSS.MS-PS1-1

If four hydrogen atoms react with two hydrogen atoms, how many atoms will be in the product?

• 6
• 4
• 8
• 2

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-1

Balance this equation-
__P₄ + __O₂ --> __P₂O₃

• it is already balanced
• 2, 1, 3
• 1, 2, 3
• 1, 3, 2

Tags

NGSS.MS-PS1-5

 Mg  +  ___ HCl  →   MgCl₂  +   H₂

• 1
• 2
• 3
• 4

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2