Science chapter 9
When a substance combines with O2 and releases energy,a_______ reaction has occured.
Combustion
True/False: The law of conservation of mass, Can three atoms of calcium can react to produce six atoms of calcium
False
True/Flase: All chemical reasctions occur at the same rate
False
What is the difference between a physical and chemical change?
Chemical chanhes ocxir with synthesis Physical changes are used to seperate diffrwnt items or substances
______________is a form of energy contained in chemical bonds.
Chemical energy
How many significant digits are in the these numbers: 063.82400
5
Breaking a chemical bond...... A. Absorbs energy from the surrondings B.releases energy into the surruondings C. Creates energy that did not not oreviously exist D.usues up energy that then no longer exists
A.absorbs energy from the surroundings
All substances.... A. are elements B. Are compunds C. have a fixes arrangement of atoms D.contain hydrogen
A.are elements
What is force
Any push or pull on an object
Endothermic reactions....... A.release more energy than they absorb B.absorb more energy than they release C.release and absorb exactly the same amount of enwrgy D.can wither release energy or absorb it
B.absorb more energy than they realease
A change in______ is a sign of energy being used in a chemical reaction. A.temperature B.color C.odor D.texture
B.color
Forming a chemical bond........ A.absorbs energy from the surrondings B.releases energy into the surrondings C.creates energy that did not previously exist D. Uses up energy that then no longer exists
B.releases energy into the surrondings
Baking soda is mised towgther what is the weight gonna be after doing the experiment? A. The orginal weight B. New added on weight C.the two equal weights that are equal the same mass
C. The two weights that equal he same mass
An exothermic reaction...... A.absorbs thermal energy B.needs energy to be added contantitly C.releases thermal energy D.needs more energy to break chemical bonds
C.releases thermal energy
Which of the following is NOT a result of a chemical reaction? A.bubbles in boiling water B.a solid forming feom two liquids reacting C.copper turning green when exposed to air D.the light given off by firefly
D. The light ficen off by a firefly
A_________slows or stops a chemical reaction. A.catalyst B.enzyme C.activator D.Inhibitor
D.Inhibitor
Which of the following is certain proof a chemical reaction has occured? A.bubbles B.change of chemical properties C.change of color D.all of the above
D.all of the above
Which one if the following factors would NOT speed up a chemical reaction? A.increasing the concentration of a reactant B.adding a catalyst C.raising the temperature D.making the reactant particles larger
D.making the reactant particles larger
A catalyst is which of the following? A.a reactant B.a product C.both a and b D.neither a or b
D.neither a or b
What change ia chemical rather than physical? A.water is boiled B.aluminum foil is crumped C.glass is shattered D.wood is burned
D.wood is burned
Dkes an endothermic or exothermic need more activation energy?
Endothermic
What is a reaction that absorbs energy?
Endothermic
What speeds up reactions in living cells
Enzyme
What is a reaction that releases energy
Exothermic
Breaking a chemical bond____________energy.
Forms
What is used to slow the spoilage of food
Inhibitor
What is present after a chemical reaction
Physical change
What substance is written to the right of an arrow?
Product
What is a measure of how fast a reaction occurs
Rate of reaction
What is present before a chemical reaction?
Reactants
What are the 5 states of matter?
Solid,liquid,gas,plasma, Bose Einstein condensate
If two or more substances combine to produce one substance, a _______ reaction has occured
Synthesis
According to the law of conservation of mass, how does the mass of the products in a chemical reaction compare to the mass of the reactants?
The masses are always equal
Explain what is meant by a balanced chemical equation
To have a balcnced chemical equation you have to have the correct formulas in order so it will all make sense
True/False: A chemcial reaction in which more energy is absorbed than is released is endothermic
True
How can you determine the rate of a chemical reaction
You can look for chanhes in porperties to find out what the rate will be
What is the reactants mass equals the product mass
conservation of mass
