Try It! Substances change states when they move between solid, liquid, and gas forms. When a substance changes from one state of matter to another, it has undergone A reduction in mass. An increase in mass. A chemical change. A physical change.

Try It! Anthony’s homework assignment is to demonstrate that an orange has already undergone a chemical change. Which of the following should he bring to class to best demonstrate a chemical change? Diced orange Rotten orange Peeled orange Mashed orange

Try It! Assembling the different ingredients to make the s’more On a camping trip, Rachel and Samuel make s’mores. They break graham crackers in half, place chocolate bars on the crackers, and roast marshmallows over the fire. When they place the hot marshmallows onto the chocolate, the chocolate melts. Which of the following actions most directly represents a chemical change? Assembling the different ingredients to make the s’more Breaking the graham crackers into two pieces Roasting the marshmallows Melting the chocolate

Benchmark C- voice level 0 H- raise hand and wait for teacher response A- guided notes M- remain in seat unless given permission P- independent Benchmark SC.8.P.9.1 Explore the Law of Conservation of Mass by demonstrating and concluding that mass is conserved when substances undergo physical and chemical changes. SC.8.P.9.2 Differentiate between physical changes and chemical changes. SC.8.P.9.3 Investigate and describe how temperature influences chemical changes.

What are physical changes of matter? one or more physical properties of a substance. -The appearance, shape, or size of a substance may be changed Physical changes, such as changes in state, do not change the chemical identity of a substance.

What are chemical changes to matter? one or more substances change into entirely new substances -Chemical changes are not the same as chemical properties. Burning is a chemical change; flammability is a chemical property.

What are chemical changes to matter? When particles and chemical bonds that make up a substance are rearranged, a chemical change has taken place. Chemical changes are often influenced by temperature. -Higher temperatures often mean faster chemical reactions.

Look for the Signs How can you tell a chemical change has happened? There are several signs that a chemical reaction has occurred. -Observing two or more of these signs during a change means you are likely observing a chemical change. Odors Fizzing and foaming The production of gas Energy that changes from one form to another Changes in temperature and color

What is the law of conservation of mass? The law of conservation of mass states that in ordinary chemical and physical changes, mass is not created or destroyed. It is only transformed into different substances.

Chemical changes are irreversible What is the law of conservation of mass? Physical changes are reversible and follow the law of conservation of mass. Mass is conserved during chemical changes. The mass of the starting materials is the same as the mass of the end products. Chemical changes are irreversible

Try It! Substances change states when they move between solid, liquid, and gas forms. When a substance changes from one state of matter to another, it has undergone A reduction in mass. An increase in mass. A chemical change. A physical change. D

Try It! Anthony’s homework assignment is to demonstrate that an orange has already undergone a chemical change. Which of the following should he bring to class to best demonstrate a chemical change? Diced orange Rotten orange Peeled orange Mashed orange B

C Try It! Assembling the different ingredients to make the s’more On a camping trip, Rachel and Samuel make s’mores. They break graham crackers in half, place chocolate bars on the crackers, and roast marshmallows over the fire. When they place the hot marshmallows onto the chocolate, the chocolate melts. Which of the following actions most directly represents a chemical change? Assembling the different ingredients to make the s’more Breaking the graham crackers into two pieces Roasting the marshmallows Melting the chocolate C

Stations (20 min each) Penda Teacher Led Lab Center ID: 32209YWLA “Changes of State” Law of Conservation of Mass mini Lab

Law of Conservation of Mass Mini Lab

ANALYZE THE DATA What was the tested (independent) variable? What was the outcome (dependent) variable? Was this a chemical or physical reaction? Was there a difference in the mass of the chemicals before and after the reaction? If so, what might be some explanations for the difference? How does your data compare to other groups data? Why did you need to be precise and accurate in your measurements? What is the Law of Conservation of Mass? How does this investigation demonstrate the Law of Conservation of Mass?