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WorksheetsChemistry
Total questions: 26
Worksheet time: 20mins
1. Liz knows that changes can alter the looks or shape of a substance.
Cutting, melting, bending, or crushing are examples of what kind of change?
reactant
product
physical
chemical
After reading about the kinds of changes that occur, Liz saw some rust on a pipe that was going into her house. What kind of change is the formation of rust?
reactant
product
physical
chemical
After learning about chemical reactions, Olivia investigated different kinds of chemical changes using substances she found in her kitchen so she could see these changes. Which of the following can occur when a chemical reaction takes place? Choose the three statements that apply.
New bonds form.
Existing bonds break.
Changes don’t affect matter.
New substances form.
Kim understands that several signs indicate a chemical reaction has occurred. What is the best way to be certain that a chemical reaction has occurred?
Some bubbles form.
A color change occurs.
A new substance forms.
The materials do not react.
Leandra is learning about chemical reactions and she wants to examine the information that is included in a chemical equation. Which pieces of information does a chemical equation include? Choose the three that apply.
the kinds of atoms that form during a reaction
the kinds of molecules involved in the reaction
the kinds of elements that make up a molecule
whether the molecules are products or reactants
One day on her walk home from school, Leann noticed some rust on an old car. She remembered that chemical equations can summarize what happens in a chemical reaction. What is the name of the two parts found on the left side of the equation below?
4 Fe + 3O 2 → 2Fe 2 O 3
products
reactants
scientific notation
synthesis
Keesha performed a chemical reaction, and the products looked quite different from the reactants. She knew the amount of matter had not changed due to the law of conservation of mass. According to the law of conservation of mass, what happens in a chemical reaction?
Matter is not created or destroyed and the same amount of mass remains.
A new kind of matter is created and the amount of mass either increases or decreases.
Matter is not created or destroyed and the amount of mass may change after the reaction.
New matter is created and changes form so that the mass of the reactants and the products will almost be equal.
James planted seeds in a pot and after a few days, a plant started to grow. It appeared that the plants carrying out photosynthesis had more mass than what was being taken in. Plants are often in a system where the matter going in and out can’t be controlled or observed. What kind of system do most plants function within?
decomposition system
manufactured system
closed system
open system
In a ________________atoms and molecules rearrange to form new ones.
Chemical reaction
Physical reaction
Physical change
Physical change
Cutting wood is an example of __________
Physical change
Chemical change
All of the above
None of the above
Slicing an apple is an example of _______
· Chemical change
· Physical change
· All of the above
· None of the above
Reactants undergo chemical reactions to form _________
· Reactants
· Catalysts
· Inhibitors
· Products
The natural resources can be ________
· Pure elements
· Simple molecules
A & B
None of the above
Digitalis lanata is an example of synthetic ______
Medicines
Foods
Fibers
Fuels
Vanillin is an example of a synthetic ______
Medicines
Foods
Fibers
Fuels
___________ is/are indication/s that a chemical reaction has occurred
Change in the energy
The formation of gas
The formation of precipitation
All of the above
When the energy released as the products form is greater than the energy required to break the bonds of the reactants. This is called ____________
Endothermic reaction
Exothermic reaction
Physical reaction
None of the above
All these are chemical changes EXCEPT __________
Bending
Burning
Rusting
New material is formed
Some endothermic reactions draw energy from the surroundings, leaving the surroundings having ____________.
High temperature (warm)
Low temperature (cold)
The same temperature
None of the above
The minimum amount of energy needed to start a chemical reaction is called _________
Thermal energy
Activation energy
Potential energy
Chemical energy
The reaction between oxygen and other flammable fuel, such as wood is an example of ____________
Exothermic reaction
Endothermic reaction
Chemical reaction
A & C
Use the image for the next question
This figure shows the __________
Endothermic reaction
Exothermic reaction
All of the above
None of the above
In a chemical reaction, the Increasing temperature will ________ the rate of the reaction.
Increase
Decrease
Not changed
None of the above
Decreasing the surface area for the reactants will make the reaction goes _________
Faster
Slower
At constant rate
None of the above
_____________ is/are factor/s that affect the rate of the chemical reaction
Surface area
Temperature
Concentration
All of the above
A material used to decrease the rate of a chemical reaction is_________
A catalyst
An inhibitor
All of the above
None of the above
