Balanced Reactions
Chemical reaction N2 + 2O2 --> 2NO2
What is, yes, this is balanced - mass is conserved.
(The left side of the reaction has 2 N atoms and 4 O atoms. The right side has the same amount. This is an example of conservation of atoms in a reaction. Since each atom has a characteristic mass, conservation of atoms causes conservation of mass.)
Sometimes scientists use chemical reactions to reclaim metals from solutions to reduce toxic waste. The metal has disappeared.
What is false? or What is the metal has not disappeared.
Two different liquids are poured into a glass beaker and a solid is formed in the beaker.
What is a chemical reaction?
The requirements for a design project.
What is criteria?
A system where reactants and products cannot enter or leave.
What is a closed system?
NH3 + HCl --> NHCl4
What is not balanced?
Will accept false.
True or False and explain
A silvery-gray piece of metal is added to a clear and colorless liquid containing acid. The metal bubbles and disappears. The liquid turns bright green. No new substances have formed.
What is false?
The bubbles show that a new substance has formed (gas) and the bright green color indicates that a second new substance has formed.
Water is added to a dark green liquid to produce a lighter green liquid.
What is a physical reaction?
The limitations on the design.
What are constraints?
An insoluble solid formed when two liquid solutions are mixed.
What is precipitate?
2H2 + O2 --> 4H2O2
What is not balanced? (unbalanced or false are accepted)
You find the mass of a beaker that has baking soda and 10 mL of vinegar. The mass before the reaction was 95.4g; the mass after the reaction was 94.3g. This system allows matter or energy to enter or escape.
What is an open system?
You boil water and bubbles form at the surface.
What is a physical reaction?
A version of the product for testing.
What is a prototype?
A chemical substance that enters into a reaction; the original substance present before a reaction takes place.
What is a reactant?
DOUBLE JEOPARDY
Heat is absorbed during this reaction, lowering the temperature of the reaction mixture, and thus the reaction flask feels cold.
What is an endothermic reaction?
Two or more atoms held together by chemical bonds.
These are not conserved during a chemical reaction.
What are molecules?
You go camping and begin to burn wood you have chopped up.
What is a chemical reaction?
Keeping track of what worked and what didn't, and then providing feedback on a design for improvements.
What is testing and evaluating the product?
The principal that nothing (atoms or mass) is created nor destroyed (gained nor lost) during a chemical reaction.
What is conserved? or
What is conservation?
Ca(OH)2 + CO2 → CaCO3 + H2O
What is balanced?
The total energy of motion of the particles in a sample of a substance.
What is thermal energy?
You have liquid A -clear and colorless; liquid B - clear and reddish in color. When the two liquids are combined in a closed system, a cloudy, yellow solution is formed.
What is a chemical reaction?
(mass is conserved).
You enjoy drinking ice water throughout the day, but your ice always melts before lunchtime in all the cups you own.
What is identifying the problem?
A change that occurs when the spacing or interactions between particles in a substance change or the particles mix with other particles. The particles themselves do not change (arrangement of atoms in the molecules do not change).
What is a physical change?