practice test

How many Hydrogen atoms are in 4H₂O?

• 6

• 8

• 2

• 4

How many Magnesium atoms are in 10MgCl₂?

• 10

• 5

• 20

How many Nitrogen atoms are in (NH₄)₂CrO₄?

• 1

• 2

• 8

• 16

What is C₂H₈O ?

• Element

• Letters

• Numbers

• Compound

What coefficient should be used to make the following equation balanced?
N₂+O₂--> _NO 

• 1
• 2
• 3
• 4

Which equation is balanced?

• PbO₂ + 2H₂

• SO₂ + H₂0 --> H₂SO₄

• 2Na + 2H₂O --> 2NaOH + H₂

Balance this equation

_Al +_HCl --> _H₂ +_AlCl₃

• 2,6,3,2

• it's already balanced

• 4,12,3,4

• 2,1,4,5

What are the coefficients that would properly balance this equation?

__Ca + __H₂O --> __Ca(OH)₂ + __H₂

• 2,1 --> 2,1

• 1,2 --> 1,1

• 1,2 --> 2,4

• 1,2 --> 2,1

In chemical compounds, covalent bonds form when

• the electronegativity difference between two atoms is very large.
• electrons are completely transferred between two metals.
• pairs of electrons are shared between two nonmetal atoms.
• two nonmetal atoms are attracted to each other by opposite charges.

An ionic bond forms when 

• Valence electrons are shared
• a sea of mobile electrons surround the cations
• valence electrons are transferred between atoms
• none of the above