Chemical Reactions and Materials Worksheet – Grade 7

A student conducts an investigation by adding two compounds together; after the reaction, the surrounding area is cooler. What type of chemical reaction has occurred?

• Endothermic reaction

• Exothermic reaction

• Combustion reaction

• Neutralization reaction

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

What are 4 signs that a chemical change has occurred? Select all that apply.

• Color change

• Formation of a precipitate (solid)

• Gas production or bubbling

• Temperature change without heating

• Change in size only

Tags

NGSS.MS-PS1-2

A student mixes water and sugar to make salt water. Sugar water is what type of substance?

• Compound

• Homogeneous mixture

• Heterogeneous mixture

• Element

How do you know sugar water is a homogeneous mixture?

• It has uniform composition because the sugar dissolves evenly throughout the water

• It contains visible chunks of sugar floating in water

• It is made of only one element

• It cannot be separated by any physical process

A student mixes water and sugar to make salt water. What is the solute and what is the solvent?

• Solute is water; solvent is sugar

• Solute is sugar; solvent is water

• Both solute and solvent are sugar

• Both solute and solvent are water

Choose the best completion: Man creates _______ materials by chemically combining chemicals that are _________ resources. An example of this man-made material is __________.

• synthetic; natural; plastic

• natural; synthetic; wood

• synthetic; renewable; rain

• natural; limited; air

Tags

NGSS.MS-PS1-3

What is another word for combustion?

• Burning

• Freezing

• Condensation

• Evaporation

Tags

NGSS.MS-PS1-5

Is combustion endothermic or exothermic?

• Endothermic

• Exothermic

Tags

NGSS.MS-PS3-4

NGSS.MS-PS3-5

How can we tell that combustion is exothermic?

• It releases energy as heat and light when fuel reacts with oxygen

• It absorbs heat from the surroundings and feels cold

• It forms a precipitate without producing energy

• It occurs only in closed containers

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-5

In a closed system, the amount of matter (or mass) ________.

• increases

• decreases

• stays the same

Tags

NGSS.MS-PS1-5