Unit 7 Chemistry Test

To balance an chemical equation, one must change the:

• coefficients
• subscripts
• superscripts
• both coefficients and subscripts

In a chemical equation, the symbol (s) following a substance means:

• the substance is aqueous
• the substance is a solid
• the substance has precipitated out of solution
• both "the substance is a solid" and "the substance has precipitated out of solution" are correct

A (g) after a molecule in a chemical equation signifies:

• the substance is grounded
• the substance is a gas
• the substance is aqueous
• the substance is found in a gnome

A substance that speeds up a reaction without being changed by the reaction is a:

• collision theory
• precipitate
• catalyst
• reactant

This symbold, →  means:

• reverse
• add heat
• gas
• yields

The energy that is required for a reaction to begin is called:

• activation energy
• catalyst
• collision theory
• reactant process

Which of the following reveals that a chemical reaction has occurred?

• a substance dissolves in solution
• a substance slows down
• heat is emitted from a substance
• there is no way to determine if a chemical reaction has occurred

Tags

NGSS.MS-PS1-2

Balance the following equation: 
Cu + AgNO₃ → Cu(NO₃)₂ + Ag

• Cu + AgNO₃ → Cu(NO₃)₂ + Ag
• Cu + 2AgNO₃ → Cu(NO₃)₂ + Ag
• Cu + 2AgNO₃ → Cu(NO₃)₂ + 2Ag
• Cu + 6AgNO₃ → Cu(NO₃)₂ + 6Ag

Write and balance the following chemical reaction:  Solid iron reacts with hydrochloric acid to give aqueous iron (II) chloride and hydrogen gas.

• Fe(s)+2HCl(aq) →FeCl₂(aq) +H₂(g)
•  Fe(s)+HCl₂(aq)→ FeCl₂(aq) + H(g)
•  Fe +   2HCl →   FeCl₂ +    H₂
  Fe₂ +  2HCl →   FeCl₂ +    H₂
• 2Fe(s) + 4HCl(aq) → 2FeCl₂(aq) + 4H(g)