Chemical Reactions

The number of atoms you begin with in a chemical reaction ...

• must be the same as the number of  atoms you end with
• must be an even number
• can be different to the number you finish with
• changes depending on how much energy is formed

Which type of reaction is:

2 NH₃ + H₂SO₄ → (NH₄)₂SO₄

• Synthesis
• Decomposition
• Single Displacement
• Double Displacement

Which type of reaction is: C₂H₄ + 3 O₂ → 2 CO₂ + 2 H₂O

• Synthesis
• Decomposition
• Single Displacement
• Combustion

Which type of reaction is:

2 K + MgBr₂ → 2 KBr + Mg

• Synthesis
• Decomposition
• Single Displacement
• Double Displacement

Provides evidence that a chemical reaction has occurred. 

• dissolving 
• melting
• formation of a gas
• bending

Which problem is balanced?

• PbO₂ + 2H₂--> H₂SO₄
• SO₂ + H₂0 --> H₂SO₄
• 2Na + 2H₂O --> 2NaOH + H₂
• 2Na + 2H₂O --> 2NaOH + H

Balance this equation.
_CF₄ + _Br₂ -- _CBr₄ + _F₂

• 2,1,2,1
• 1,2,2,1
• 1,2,1,2
• 2,2,2,2

In a reaction A + B ----> C,  reactant A has 5g and product  C has 9g. How many grams does reactant B should have? 

• 4g
• 5g
• 9g
• 14g

In the reaction AB-----> A + B reactant AB has 12g and product B has 5g. How many grams should product A have?

• 17g
• 2g
• 7g
• None of the above

In a chemical reaction, 4 grams of sodium must combine with how many grams of chlorine to produce 10 grams of table salt?

• 4 grams

• 6 grams

• 8 grams

• 10 grams