CHEMICAL EQUATION

means: shows  a chemical reaction using symbols/formulas

ex: 1 C + 2 O = CO2

      2 H + 1 O = H2O

means:  the substances at the beginning of a chemical equation

ex:  CaCO₃      yields ------       CaO + CO₂

      reactant -------------------     products

means:  the new substances after the reaction is complete

ex:   CaCO₃     yields ----------     CAO + O₂

        reactant                              products

OPEN SYSTEM

means:  matter can enter or escape to the surroundings

ex.:  a burning match releases oxygen in air

        a fire releases products (oxygen, gas, smoke) in air

means:  during a chemical reaction, matter is is not created or destroyed.

ex:  conserve=save

****All atoms present at beginning of reaction are still there at end of reaction

means:  matter is not allowed to enter or leave...it is contained

ex.:  a pear decaying under glass

        bacteria growing in a closed petri jar

means:  a number placed in front of chemical formula in an equation....used to balance equations

ex:  2 H₂O + O₂ -----  2 H₂O

means:  put things together...2 or more elements or compounds combine = more complex substance

ex.:  H + O₂ = Water

      hydrogen + oxygen = water

means: breaks down the compounds into smaller products.....opposite of synthesis

ex.:  2 H₂0₂ ----- 2H₂0 + 0₂

  hydrogen peroxide ----- water + oxygen gas

means:  one element replaces another ...or...2 elements in 2 different compounds trade places

ex.:  2 Cu₂O + C------- 4Cu + CO₂

  the 2 oxygens were traded to the C to make CO₂

means:  the amount of energy needed to start (activate) the chemical reaction

ex.:  electric spark ---activates (starts) the reaction between hydrogen and oxygen in water....

means:  the amount of substance in a given volume

ex:  Orange juice includes mostly water mixed with orange concentrate.....

       Orange juice concentrate is the solid form of just orange.  You have to add water to make it juice...

means:  increases the rate of reaction (makes it happen faster)

ex:  heating up a mixture increases the rate of how fast it changes....so heat can be a catalyst....boiling water

means:  biological catalysts.....make chemical reactions necessary for life happen at a low temperature.

ex:  enzymes in your body break down the food you eat

means:  decreases ( inhibits) the rate of reaction....prevent reactants from coming together

ex:  preservatives added to food slow down the reactions so food doesn't spoil

means:  a rapid reaction between oxygen and a fuel that causes fire

ex:  when gas (fuel) + oxyegen + heat = FIRE

means:  a material that releases energy when it burns.

ex:  gas, oil, wood, paper