Question

lesson objective students will differentiate between physical and chemical changes and explain whether a phase change is a physical change using a claim - evidence - reasoning (cer) framework. language objective students will use scientific vocabulary (e.g., phase change, physical change, chemical change, substance, evidence, reasoning) and complete evidence frames in written and spoken cer in speaking and writing. build background - physical change: changes the form or state of matter but does not make a new substance (melting butter, boiling water, dissolving sugar, breaking glass). - chemical change: produces a new substance with new properties. - examples: frying an egg, burning wood, rusting iron, baking bread. chemical and physical changes chemical change: a physical change: matter chemical reaction forms changes form but not new products. chemical identity. combustion rotting melting shredding rusting digestion boiling chopping sciencenotes.org cer framework instruction - answer the guiding question: is a phase change a physical or a chemical change? - use the word bank to help you include scientific vocabulary in your writing. - support your claim (your answer to the question). - write at least 2 pieces of evidence about phase changes. - write your reasoning to explain how your evidence supports your claim. word bank phase change physical chemical substance state new evidence reasoning state of solid, liquid, gas melt freeze boil condense properties remains the same changes evidence this permanently always... process... claim answer the question: is a phase change a physical or chemical change? - i claim that a phase change is a ____ change because evidence use at least 2 pieces of evidence: - my evidence is that when a __ happens, the substance is still __. - another piece of evidence is reasoning explain why your evidence supports your claim: - this evidence supports my claim because a __ change means - a chemical change would __ but in a phase change __. - therefore, a phase change is a ____ change.

Explanation:

A phase change is a physical change because the substance's chemical identity remains the same. For example, when water boils (a phase - change from liquid to gas), it is still water chemically. Another example is when ice melts (solid to liquid), it is still H₂O. Physical changes only alter the form or state of matter, not its chemical composition. Chemical changes, on the other hand, form new substances with different chemical properties.

Answer:

Claim: I claim that a phase change is a physical change because the chemical identity of the substance remains the same during a phase change.
Evidence: My evidence is that when a solid melts into a liquid, the substance is still the same substance chemically. Another piece of evidence is when a liquid boils into a gas, the chemical composition of the substance does not change.
Reasoning: This evidence supports my claim because a physical change means the form or state of matter changes but the chemical identity remains the same. A chemical change would form a new substance with different chemical properties but in a phase change, the substance's chemical nature stays the same. Therefore, a phase change is a physical change.