Chemical change and reactions

In a chemical reaction, bonds are broken and new bonds are formed that create new substances. The bonds that are broken are called what?

• Reactants
• Products
• Atoms
• Catalysts

Tags

NGSS.MS-PS1-2

Which of these is NOT a sign that a chemical change has occurred? 

• A loss of transparency 
• An unexpected color change
• A temperature change
• The formation of a precipitate

Tags

NGSS.MS-PS1-2

How many Al atoms are in this compound?         4Al₂O₃

• 2
• 8
• 6
• 4

Tags

NGSS.MS-PS1-1

Describes the number of molecules in a compound and is used to balance a chemical reaction. 

• coefficient 
• subscript
• superscript
• SI unit

Tags

NGSS.MS-PS1-5

Which type of reaction takes place in the presence of oxygen and produces carbon dioxide and water?

• double replacement 
• decomposition 
• combustion 
• single replacement

Tags

NGSS.MS-PS1-2

A compound is reacted and forms two new substances. What type of reaction is this? 

• combustion 
• synthesis 
• decomposition 
• single replacement 

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Identify this type of reaction,
Cl₂ + 2KI _-->  I₂ + 2KCl

• Synthesis
• Single displacement
• Double displacement
• Decomposition

Which of the following describes a precipitate?

• a liquid forms when a block of metal is heated
• a solid forms when one liquid is poured into another
• a gas forms when a solid is placed in a liquid
• bubbles form when an acid is poured on a rock

Tags

NGSS.MS-PS1-2

The force that holds 2 atoms together is called a ________________.

• Chemical Reaction
• Chemical Bond
• Diatomic Chemical
• Glue

Tags

NGSS.HS-PS1-4

Three beakers labelled as A, B and C each containing 25 mL of water were taken. A small amount of NaOH, anhydrous CuSO4 and NaCl were added to the beakers A, B and C respectively. It was observed that there was an increase in the temperature of the solutions contained in beakers A and B, whereas in case of beaker C, the temperature of the solution falls. Which one of the following statement(s) is(are) correct?(i) In beakers A and B, exothermic process has occurred. (ii) In beakers A and B, endothermic process has occurred. (iii) In beaker C exothermic process has occurred. (iv) In beaker C endothermic process has occurred.

• (i) only
• (ii) only
• (i) and (iv)
• (ii) and (iii)

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-4