Stoichiometry

What is the percent composition by mass of sulfur (S) in the compound MgSO₄?

• 20.22%

• 19.85%

• 26.64%

• 28.64%

Theoretical yield = 73g
Actual yield = 62g
Calculate the percent yield.

• 16%

• 116%

• 85%

• 76%

Tags

NGSS.HS-PS1-7

Balance this equation:
P₄+O₂  -->  P₂O₃

• 3 P₄+ O₂ --> 2 P₂O₃

•  P₄+ O₂ --> 2 P₂O₃

•  P₄+ 3 O₂ --> 2 P₂O₃

•  P₄+ 2 O₂ --> 3 P₂O₃

Tags

NGSS.MS-PS1-5

2CO  +  O₂  −-> 2CO₂
How many liters of carbon dioxide are produced from 10L of carbon monoxide?

• 10

• 20

• 1

• 5

Tags

NGSS.MS-PS1-5

How many atoms of aluminum are on each side of the following equation: 4Al + 3O₂ --> 2Al₂ O₃

• 2

• 6

• 1

• 4

Tags

NGSS.MS-PS1-1

At the end of chemical reactions, what is the total mass of the reactants compared to the total mass of the products?

• the product is doubled

• the product is half the mass of the reactants

• the mass is the same

• the mass changes depending on the reaction

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

Balance this equation,            
Al₂O₃ --> Al + O₂ 

• Cannot be balanced

• 2Al₂O₃ --> 2Al+3O₂ 

• 2Al₂O₃--> 4Al+3O₂ 

• 3Al₂O₃--> 2Al+O₂ 

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

What is the total number of atoms present in 5Na₃PO₄

• 5

• 40

• 55

• 8

Tags

NGSS.MS-PS1-1

What are the larger numbers that you CAN CHANGE in a chemical equation? 

• Coefficient 

• Products

• Reactants

• Subscripts