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WorksheetsUnit 2 Chemical reactions
Total questions: 21
Worksheet time: 12mins
A substance that takes part in and undergoes change during a chemical reaction
product
reactant
mass
yields
How are fireworks an example of chemical reactions?
they are made of chemicals
heat, light, and sound are given off
the chemicals do not change as they explode
fireworks are examples of physical changes
Check all the ones that are PHYSICAL changes
ice melting
vinegar + baking soda reacting
cutting paper
burning paper
Physical and chemical characteristics of matter used to describe and identify a substance
reactions
properties
changes
products
3HN
3NH
NH3
H3N3
Air is a _________ because there are different molecules and atoms together that are not chemically bonded
reaction
reactant
pure substance
mixture
pure substance
mixture
Sodium & Chlorine react to form salt. how do we know a chemical reaction has taken place?
chlorine is a gas and sodium is a solid
sodium and chlorine rearrange to form a new molecule
they're all salty
sodium is bigger
2 clear chemicals combine. The solution turns yellow & gets cold. What evidence suggests that a chemical change took place?
There's no evidence
The solution got cold
The solution turned yellow
it evaporates
Rust forming on a piece of iron is an example of which of the following:
A physical change because the process can be reversed
The natural process of decay as metallic ions age
A chemical change because oxygen atoms from the atmosphere bonded with the iron atoms
Which of the following is NOT an indicator of a chemical reaction?
phase change
temperature change
precipitate or gas produced
color change
does this show the law of conservation of mass correctly?
yes
NO!
the PRODUCT(s) in elephant toothpaste?
hydrogen peroxide
hydrogen water
foam
water and oxygen
physical properties
flammability
reactivity
color
texture
3. The substances listed on the left side of a chemical equation are the
reactants
products
yields
molecules
What does the law of conservation of mass mean?
atoms usually die after a chemical reaction
the mass of atoms that go through a chemical reaction equals to the mass of the products
atoms can be created (like plants)
atoms have a short life span
Does this show the law of conservation of mass?
NO!
YES!
what is the chemical formula?
4C2H2
C2H4
2C2H4
C2H8
There's 3 molecules and 1 atom
There's 1 molecule and 3 atoms
there's 1 molecule of carbon and 2 molecules of oxygen
there's 3 molecules and 3 atoms
Check all that describe chemical changes
new substances are formed
fireworks is an example
rotting fruit is an example
new substances have different properties
