Writing Equations Chemistry

In chemical reactions, what does the principle of conservation of mass mean?

• Matter is not created or destroyed.
• The total mass of the reactants is greater than the total mass of the products.
• The total mass of the reactants is less than the total mass of the products.
• Matter is not changed.
  

Tags

NGSS.HS-PS1-7

Identify the reactant(s) and product(s) of the reaction.

• All three are reactants and none are products.
• Hydrogen and water are the reactants, and oxygen is the product.
• Water and oxygen are the reactants, and hydrogen is the product.
• Hydrogen and oxygen are the reactants, and water is the product.
  

How many Hydrogen (H) atoms are in NH₃O5

• 3
• 4
• 5
• 1

Tags

NGSS.MS-PS1-1

What state of matter is this substance?

• solid

• liquid

• gas

• aqueous

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

Identify the number in blue.

• Product

• Reactant

• Coefficient

• Subscript

Tags

NGSS.HS-PS1-7

Which compound is formed as a precipitate in this reaction?

• Pb(NO₃)₂

• KI

• PbI₂

• KNO₃

When dry ice (solid carbon dioxide) sublimes it goes directly from a solid to a gas. What type of change is occurring? 

• Chemical change
• Physical change
• None of the above 

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

Which of the following is evidence that a chemical change has taken place? 

• change in color
• change in size
• change in shape
• change in energy

Tags

NGSS.MS-PS1-2

Write a balanced equation for the reaction of aqueous solutions of potassium sulfide and hydrochloric acid.

• K₂S_(aq) + 2 HCl_(aq) → 2 KH_(aq) + SCl_2(g)
• K₂S_(aq) + HCl_(aq) → HS_(g) + KCl_(aq)
• K₂S_(aq) + 2 HCl_(aq) → H₂S_(g) + 2 KCl_(aq)
• K₂S_(aq) + 2 HCl_(aq) → 2 K_(s) + H_2(g) + SCl_2(g)

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Is the following equation word, skeleton or ionic?
Mg _(s) + Br_{2 (g)} --> MgBr_2 (aq)

• Word Equation
• Skeleton Equation
• Ionic Equation
• None of the above