Chemical Equations
Chemical Changes
Chemical vs. Physical Changes
Atoms and Molecules
Conservation of Mass
100
What do we call the substances that react in a chemical reaction, written on the left side of a chemical equation?
Reactants
100
What do we call a process by which two or more chemical substances interact and are chemically changed, producing different chemical substances?
Chemical reaction
100
In a physical change, a new substance (is/is not) created.
Choose is or is not.
Is not
100
What is a molecule?
2 or more atoms
100
What is the law of conservation of mass?
MATTER CANNOT BE CREATED OR DESTROYED.
200
Magnesium sulfate + sodium bicarbonate → ________________ sulfate + magnesium bicarbonate
sodium
200
What's one observable sign of a chemical reaction?
There's lot's of answers, e.g.:
a temperature change
the formation of a precipitate
an explosion
light is released
a color change
a gas is released
200
Cutting a piece of paper is an example of a ________ change.
Physical
200
What are the 3 parts, or subatomic particles, that make up atoms called? And what are their charges (positive, negative, or neutral)?
Protons, (+)
Electrons, (-)
Neutrons, (neutral)
200
What is mass?
Mass is how much something weighs.
300
Write a word equation that models how mercury metal and oxygen combine to form mercuric acid:
___________ + __________ --> _________________
mercury metal + oxygen --> mercuric oxide
300
Teacher Angel is cleaning up the science lab and notices that during the lab, a thick solid substance formed at the bottom of the beaker of calcium chloride and sodium bicarbonate. What is this substance called, and what is it a sign of?
This substance is called a precipitate.
It is a sign of a chemical reaction.
300
Bacteria forming inside a container of spoiled milk is an example of a ________ change.
Chemical
300
If red represents hydrogen (H) atoms, and blue represents carbon (C) atoms, write the chemical equation for this molecule.
CH4
300
In a chemical reaction, the mass, or weights, of the products and the reactants are:
1) Different
2) The same
3) It depends on the reaction
2) THE SAME.
400
Balance the following chemical equation.
__H2 + __O2 --> __H2O
2H2 + O2 --> 2H2O
400
What happens to the atoms in a chemical reaction?
They rearrange to form new molecules.
400
Alfonza has some delicious ice cream that he got on a hot summer day. To his dismay, his ice cream begins to melt in the heat from the sun. Did Alfonza's ice cream go through a physical or a chemical change?
Physical
400
Compounds are molecules that contain more than one element. Which of the following molecules are compounds?
H2
C4H5
NaCl
Fe2
Br3
H2O
C4H5
NaCl
H2O
400
If we have 2 grams of oxygen gas that combines with 1 gram of hydrogen gas in a chemical reaction and produces water, how many grams of water did we produce?
3 grams of water
500
Balance the following chemical equation:
__P + __O2 --> __P2O5
4P + 5O2 --> 2P2O5
500
In a chemical reaction, when atoms rearrange, can matter be created or destroyed?
No. Matter cannot be created or destroyed. This is called the law of conservation of mass.
500
Which of the following are chemical properties--meaning, in order to observe them, we have to change the chemical composition of a substance?
flammability
shape
reactivity to water
volume
boiling point
luster
pH
flammability, reactivity to water, and pH
500
Draw an accurate model of this atom:
500
Make up your own chemical equation using real elements and BALANCE it to reflect the law of conservation of mass.
Answers may vary! As long as there are equal amounts of atoms on each side, you're correct!