Chemical reactions and equations

Chemical reactions and equations

by John Toje

Chemical Reactions

Chemical Reactions

are chemical changes in which one or more substances are converted into new substances.

Reactants and Products

• Substances that enter the reaction and react with each other are called reactants.

• Substances that are formed are called products.

• Simple example - BAKING A CAKE!

Multiple Choice

The reactants in the image above are:

• CH4 and 2 O2

• 2 H2O and CO2

• All of these are reactants

• All of these are products

Multiple Choice

A substance that is formed as the result of a chemical reaction is a __________________

• Product

• Reactant

• Starters

• Enders

Multiple Choice

How do we know that a chemical reaction happened?

• New substance was formed.

• Substances changed size.

• Substance turned from solid to liquid.

• Substance split into pieces.

Endothermic Reactions

• Endo = Taking in

• Thermos = Heat

• Chemical reactions that need an input of heat to happen.

• Eg. Caramelizing sugar

Exothermic

Reactions

• Exo = Out of

• Thermos = Heat

• Chemical reactions that release heat as they happen.

• Eg. Burning fire

Multiple Choice

Fireworks

• ENDOTHERMIC

• EXOTHERMIC

Multiple Choice

If a chemical reaction is EXOTHERMIC, the temperature would....

• Stay the same
• Increase
• Decrease

Multiple Choice

Frying eggs

• ENDOTHERMIC

• EXOTHERMIC

Multiple Choice

Photosynthesis

• ENDOTHERMIC

• EXOTHERMIC

Indicators of Chemical Change

• Change in temperature

• Change of colour

• Change of smell

• Formation of gass/bubbles

• Formation of precipitate

Multiple Choice

What reaction has the following general formula:

A + B --> AB

• Synthesis

• Decomposition

• Single Displacement

• Double Displacement

• Combustion

Multiple Choice

What type of reaction is the following: $$2H_2+O_2->2H_2O$$  

• Synthesis

• Decomposition

• Single Displacement

• Double Displacement

• Combustion

Multiple Choice

What is the general reaction scheme for a decomposition reaction?

• A + B --> AB

• AB --> A + B

• A + CD --> C + AD

• AB + CD --> CB + AD

• $$C_xH_y+O_2\ ->\ CO_2+H_2O$$

Multiple Choice

2 NO₂ --> 2 O₂ + N₂

• Synthesis

• Decomposition

• Single displacement

• Double displacement

Multiple Choice

What reaction has the following general formula:

A + CD --> C + AD

• Combination

• Decomposition

• Single Displacement

• Double Displacement

• Combustion

Multiple Choice

What type of reaction is the following: $$3CuS\ +2Al\ ->\ Al_2S_3+3Cu$$

• Combination

• Decomposition

• Single Displacement

• Double Displacement

• Combustion

Multiple Choice

What reaction has the following general formula:

AB + CD --> CB + AD

• Combination

• Decomposition

• Single Displacement

• Double Displacement

• Combustion

Multiple Choice

2 NaBr + 1 Ca(OH)₂ ----> 1 CaBr₂ + 2 NaOH

• Synthesis (or combination)
• Decomposition
• Single displacement
• Double displacement

Multiple Choice

What reaction has the following general formula: $$C_xH_y\ +\ O_2\ ->CO_{2\ }+\ H_2O$$  

• Combination

• Decomposition

• Single Displacement

• Double Displacement

• Combustion

Multiple Choice

What type of reaction is the following: $$2C_4H_{10}\ +13O_2\ ->\ 8CO_2+10H_2O$$

• Combination

• Decomposition

• Single Displacement

• Double Displacement

• Combustion