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The law of conservation of mass states that ...
Mass cannot be created nor destroyed on transformed. The mass of the reactants must equal the mass of the products (Closed system)
How is a chemical change different than a physical change?
Physical change the chemical composition stays the same. Chemical change something new is made- molecules break and make new bonds creating new materials.
What is an acid?
a substance with H+ ions
What is a base?
A substance with extra OH- ions
What is matter?
Anything that has mass and takes up space.
Which substance is most acidic on the pH scale?
A. Hydorcloric Acid (pH= 0)
B. Black Coffee (pH=5)
C. Soapy Water (pH=12)
D. Bleach (pH=13)
A. Hydrochloric Acid
2H2 + O2 = 2H2O
What is true?
A. The equation is balanced
B. The equation is not balanced
C. New elements were formed as a result of the reaction.
D. Some atoms disappeared as a result of the reaction.
B. The equation is balanced
Which substance would be considered a weak base on this pH scale?
A. Urine (6)
B. Soapy Water (12)
C. Distilled Water (7)
D. Sea Water (8)
D. Sea Water
What happens when heat is added to a reaction?
The reaction happens faster (Glow sticks)
Which activity is an example of a chemical change?
A. dissolving salt in water
B. Hammering aluminum into thin sheets
C. Melting gold to make jewelry
D. Burning wood to produce ashes
D. Burning wood.
Which process is an example of a physical change?
A. Burning coal
B. Cutting a marshmallow
C. A rotting apple
D. Milk turning sour
B. Cutting a marshmallow
What is an endothermic reaction, include making or breaking bonds and absorbing or releasing heat in your answer.
In endothermic reactions, the energy needed to break existing bonds is greater than the energy released when new bonds are formed. Resulting in the reaction being cold.
What is an exothermic reaction?
In exothermic reactions, more energy is released when the bonds are formed in the products than is used to break the bonds in the reactants. Exothermic reactions are accompanied by an increase in temperature of the reaction mixture.
Which of the following shows an endothermic reaction?
A. When CaCl is added to water the temp goes up.
B. When baking soda is added to CaCl, the temp goes down
C. When Alka-Seltzer is mixed with water, the temp goes up
D. When a glow stick is cracked, light is given off.
B. When baking soda is added to CaCl, the temp goes down
Which is considered a compound?
A. A noble gas
B. Salt dissolved in water
C. Carbon chemically combined with oxygen
D. Chex Mix
C. Carbon chemically combined with oxygen
How many Nitrogen are in the following compound C7H6(NO2)3?
3
DAILY TRIPLE:
List 5 properties of ACIDS
List 5 Properties of BASES
-Slippery
-Bitter
-Does not conduct electricity
-turns litmus paper blue
-8-14
List 5 signs of a chemical reaction.
Precipitate
Bubbles (Gas production)
Color Change
Change in temperature
Light given off
Odor
List 5 properties of Physical Changes.
Expected color change ·
Change in size or shape ·
Change in state of matter ·
Reversible ·
No new substance formed!
What respective sides are the reactants and products on in a chemical reaction?
Reactants = Left
Products = Right
When two liquids make a solid.
What happens when a base and an acid are combined?
The process of neutralization occurs and salt and water is made.
Litmus turns what color for each acid and base?
Litmus=Red=Acid
Litmus=Blue=Base
DAILY DOUBLE: What does pH stand for?
Percent of HYDROGEN
What are the two ranges for acids and bases?
What pH is neutral-give an example.
0-6 Acid
8-14 Base
Neutral = Distilled H20