Review Law of Conservation of Mass

What is the total number of atoms present in 5Na₃PO₄? (remember, a coefficient is a multiplier and Elements without a number is 1)

• 5

• 55

• 40

• 8

Tags

NGSS.MS-PS1-1

What is the right part of a chemical equation called?

2H₂ + O₂ ---> 2H₂O

• Reactants

• Yields

• Products

• Chemical Equation

What is the little number after an element in a chemical equation called?

Example: H₂

• Coefficient

• Atom

• Subscript

• Equation

What is the number before a chemical formula called?

Example: 2H₂ + O₂ ---> 2H₂O

• Coefficient

• Atom

• Subscript

• Equation

In the equation, 2Mg + O₂ ---> 2MgO, which are the reactants?

• Mg and O

• Mg and MgO

• MgO

• O and MgO

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

Balance this equation:

H₂ + Cl₂ ---> HCl

• It is balanced.

• H₂ + Cl₂ ---> 2HCl

• 3H₂ + Cl₂ ---> 6HCl

• H₂ + 3Cl₂ ---> 6HCl

Tags

NGSS.MS-PS1-5

Balance this equation:

HgO ---> 2Hg + O₂

• It is balanced.

• 2HgO ---> 2Hg + O₂

• 2HgO ---> Hg + O₂

• HgO ---> Hg + 2O₂

Tags

NGSS.MS-PS1-5

How many HCl molecules do you need to balance this equation? 
Mg +  __HCl --->  MgCl₂ + H₂

• 1
• 2
• 3
• 4

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

What law governs the balancing of chemical equations? 

• Law of Energy
• Law of Conservation of Matter/Mass
• Law of Gravity
• Law of Matter Movement 

Tags

NGSS.MS-PS1-5

The compound ammonia is composed of nitrogen and hydrogen atoms. If two atoms of nitrogen completely react with six atoms of hydrogen to form two molecules of ammonia, which best describes the number of hydrogen atoms present in the two molecules of ammonia?

• 2

• 4

• 6

Tags

NGSS.MS-PS1-1