Chemical Equations

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

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

How many oxygen atoms are present in the following? 
4Ca(OH)₂

• 4
• 6
• 8
• 1

Tags

NGSS.MS-PS1-1

Why must we balance chemical equations? 

• Our teacher said so
• to abide by the law of conservation of energy
• to abide by the law of conservation of mass

Tags

NGSS.MS-PS1-5

What is changed in a chemical reaction like this one? 
NaOH + HCl   →  NaCl + H₂O

• the number of atoms is changed
• molecules and compounds are changed 
• atoms are changed
• elements are changed 

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

Which of the following is true? 

• Na is a gas
• Cl combusts when put in water
• NaCl is very different than Na and Cl
• Cl is a metal

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-1

NGSS.MS-PS1-2

How many E atoms are there in this silly formula?
2E₂Fg₃Hi₄

• 4
• 2
• 1
• 3

Tags

NGSS.MS-PS1-1

Which of the following can be broken apart in a chemical reaction? 

• Noble gases
• Molecules and compounds
• only molecules
• only compounds 

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-2

 Fill in the blank to balance the chemical equation. 
2KI  +  ____Cl₂ →  2KCl  +  I₂

• 1
• 2
• 3
• 4

Tags

NGSS.MS-PS1-5

What coefficient should go in the blank space to balance the chemical equation? 
2Al  +____  HCl   →    2AlCl₃  +  3H2

• 2
• 4
• 3
• 6

Tags

NGSS.MS-PS1-5