A CHEMICAL REACTION occurs when bonds between atoms are broken.
CHEMICAL EQUATION is a short way of describing the changes that occur during the chemical reaction.
The substances that react during a chemical reaction are called the REACTANTS.
The substances that are produced are called the PRODUCTS.
The symbol → called a yield sign, means "PRODUCES" or "YIELDS".
The + sign means "AND" or "ADD".
The following symbols can be used after the chemical formulas to indicate the state of each of the reactants and products in a chemical reaction:
s means "SOLID" ( Solids can be also labeled c if they look like crystals.)
l means " LIQUID"
g means "GAS"
aq means "AQUEOUS" or "DISSOLVED IN WATER".
CHEMICAL EQUATION is a short way of describing the changes that occur during the chemical reaction.
The substances that react during a chemical reaction are called the REACTANTS.
The substances that are produced are called the PRODUCTS.
The symbol → called a yield sign, means "PRODUCES" or "YIELDS".
The + sign means "AND" or "ADD".
The following symbols can be used after the chemical formulas to indicate the state of each of the reactants and products in a chemical reaction:
s means "SOLID" ( Solids can be also labeled c if they look like crystals.)
l means " LIQUID"
g means "GAS"
aq means "AQUEOUS" or "DISSOLVED IN WATER".
Why Chemical Reactions are necessary?
There are many chemical reactions. They all are important. Yet, some are crucial for our lives. Because, we need energy, and chemical reactions produce this energy for us. Let's answer some other questions as follow then:
There are many chemical reactions. They all are important. Yet, some are crucial for our lives. Because, we need energy, and chemical reactions produce this energy for us. Let's answer some other questions as follow then:
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What ATP is and How it works?
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Photosynthesis and Cellular Respiration
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An example of an anaerobic reaction: fermentation
WHAT IS COMBUSTION?
A combustion reaction occurs when oxygen combines with another compound to form water and carbon dioxide. Combustion reactions produce energy in the form of heat.
COMBUSTION requires O2 and produces CO2 AND H2O
What is Rusting?
Corrosion is the loss of metallic properties of a metal due to oxidation and is accompanied by the formation of unwanted products.
Copper, iron and aluminum metals all corrode over time loosing strength and electrical conductivity.
Rusting is the corrosion of iron and readily occurs in the alloy steel. The formation of a reddish brown flakes which loosely adheres to the iron is called rust.
Steel is an alloy made of iron and carbon. The carbon atoms in steel greatly increase the strength of the metal. They prevent the iron atoms in the crystal lattice from slipping over one another.
Steel is widely used in the manufacture of cars, white goods and the construction industry because it is much stronger than iron.
The carbon atoms in steel however, greatly decrease the ability of iron to resist corrosion.
The overall chemical equation for the formation of rust is
Iron + water + oxygen rust
4 Fe(s) + 6 H2O(l) + 3 O2(g) 4 Fe(OH)3(s)
Iron(III) hydroxide, Fe(OH)3 then dehydrates to produce Fe2O3.nH2O(s) or rust
Neutralization Reactions: Acid-Base Reactions
- When an acid and a base are placed together, they react to neutralize the acid and base properties, producing a salt.
- The H(+) hydrogen ions (cation) of the acid combines with the OH(-) hydroxide ions (anion) of the base to form water.
- The compound formed by the cation of the base and the anion of the acid is called a salt.
EXAMPLE: OUR BALLOON ACTIVITY!!! :)
The acetic acid (vinegar) and sodium bicarbonate (baking soda) combine to make water, sodium acetate (a salt) and carbon dioxide. The carbon dioxide (CO2) is the gas that blows up the balloon and eventually causes it to burst. The reaction looks like this:
Vinegar +baking soda =water+ salt + carbon dioxide
the acetic acid + sodium bicarbonate = water +sodium acetate + carbon dioxide
CH3COOH + NaHCO3 --> H2O + NaOCOCH3 + CO2
It is an endothermic reaction, which means that it needs heat to work, so it will feel cold in your hands.
DEMOS & ACTIVITY
DEMO 1: sodium polyacrylate and water chemical reaction
DEMO 2: mysterious solid and a solution.
OBSERVE AND DISCUSS- WHAT TYPE OF REACTION IS IT?
YOUR TURN: Growing oorbeezzzz
In your tray you will have four cups.
-orbeez for each cup
Cup 1: water
Cup 2: salty water
Cup 3: sugary water
Cup 4: an unknown solution for each team
After placing the solution in your cups, put them in front of you.
YOUR TASKS:
- to write each cup's expected chemical reaction formula
(for example 5 small orbeez + water = .....)
-to observe to see the end products.
-then write a nice description about the products for each reaction by working together with your team-mates.
-next, we will have a brief class discussion based on your results.
DEMO 2: mysterious solid and a solution.
OBSERVE AND DISCUSS- WHAT TYPE OF REACTION IS IT?
YOUR TURN: Growing oorbeezzzz
In your tray you will have four cups.
-orbeez for each cup
Cup 1: water
Cup 2: salty water
Cup 3: sugary water
Cup 4: an unknown solution for each team
After placing the solution in your cups, put them in front of you.
YOUR TASKS:
- to write each cup's expected chemical reaction formula
(for example 5 small orbeez + water = .....)
-to observe to see the end products.
-then write a nice description about the products for each reaction by working together with your team-mates.
-next, we will have a brief class discussion based on your results.
The results of the following reactions:
cup 1: water + orbeez
cup 2: water + salt + orbeez
cup 3: water + salt + orbeez
cup 4: water + oil + orbeez
cup 5: water + detergent + orbeez
cup 6: water + vineger + orbeez
cup 6: water + baking soda + orbeez
cup 1: water + orbeez
cup 2: water + salt + orbeez
cup 3: water + salt + orbeez
cup 4: water + oil + orbeez
cup 5: water + detergent + orbeez
cup 6: water + vineger + orbeez
cup 6: water + baking soda + orbeez
CHEMICAL AND PHYSICAL CHANGES
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DEMOS, EXPERIMENTS, DISCUSSIONS...
1.Mixtures: LET'S MAKE A LAVA LAMP
2. Solutions: class discussion :)
3. Compounds: HAVE YOU EVER GROWN CRYSTALS BEFORE?
1.Mixtures: LET'S MAKE A LAVA LAMP
2. Solutions: class discussion :)
3. Compounds: HAVE YOU EVER GROWN CRYSTALS BEFORE?