Physical Change
True or False. A change in size, shape, or state of matter is a physical change?
True
True or False. Physical properties of a substance can be observed and measured without changing the identity of that substance.
True
True or False. A chemical change happens when one or more substances are changed into new substances.
True.
True or false, the following is a definition of a chemical property. A characteristic that shows how a substance will react with other substances.
True.
What type of graph uses points that are connected to show a pattern or trend.
Line Graph.
True or False. A new substance is made when a substance undergoes a physical change.
What do you use in order to observe a physical property?
Senses- Sight, smell, taste, touch etc.
What do the particles and chemical bonds do what a chemical change occurs?
Rearrange.
How easily something reacts with something else OR its ability to combine with another substance to form a new substance is called what?
Reactivity.
True or False. The control variable is graphed on the x-axis.
False.
A piece of aluminum foil is crumpled into a ball. How do you know this is a physical change and not a chemical change?
This is because you are changing the shape and size of the aluminum foil not making it a new substance.
This physical property measures how easily electricity can flow through a material.
A student mixes vinegar and baking soda, and the mixture bubbles as carbon dioxide gas is released. Why is this reaction considered a chemical change?
This is a chemical change because new substances are produced and bubbles of gas form.
Which chemical property is being described? Substances that can cause harm to a living organism when it reacts with the body’s cells.
Toxicity.
Correctly state the name and place were both variables are graphed in science.
Independent variable- x-axis
Dependent variable- y-axis
Water in a mud puddle dries as the sunlight hits it during the day. Describe why this is a physical change and not a chemical change.
The water evaporated into the air due to the sunlight. It is still water but in a different state of matter.
This physical property measures how something can be pulled, stretched, or shaped.
Ductile
Name four signs that you know a chemical change has occurred.
Fizzing, Production of energy (Heat or Light), New substance is formed, Development of gas, Foaming, Change in Odor, Sound given off etc.
You pour sugar into a cup of water and stir it. You notice that the sugar dissolves. Is this describing a scenario in which a chemical property is defined? If yes why? or not why?
No, this scenario is describing solubility which is a physical property.
Liam wants to see how the type of liquid affects how fast sugar dissolves. He fills three clear cups with the same amount of water, juice, and milk. He then adds one teaspoon of sugar to each cup at the same time and stirs each for 30 seconds. Liam observes which liquid dissolves the sugar the fastest. Correctly name the independent and dependent variables.
Independent Variable: The type of liquid (water, juice, milk).
Dependent Variable: How fast the sugar dissolves.
A blacksmith heats a piece of iron until it glows red and then hammers it into a new shape. Explain why this is still considered a physical change and not a chemical change.
This is because the blacksmith is adding heat and force to only change the shape of the iron not changing the chemical composition of the iron.
Explain in your own words the differences in a physical and chemical property.
A physical property tells you what it looks like or how it behaves without changing it.
A chemical property tells you what it can do if it changes into something new.
Hydrogen peroxide (H₂O₂) slowly breaks down when left in sunlight, forming water and oxygen gas.
Explain why this process is a chemical change and not a physical change.
This is a chemical change because the original compound hydrogen peroxide (H₂O₂) decomposes into entirely new substances.
A scientist mixes two clear solutions and notices a yellow solid forms, along with bubbles and heat. Identify at least TWO chemical properties shown in this reaction and explain your reasoning.
Reactivity – the substances reacted to form new products.
Formation of a precipitate – the yellow solid is a new substance that is formed.
Gas production – the bubbles indicate a chemical change.
Scenario:
Maya is in the science lab testing how temperature affects the rate of a chemical reaction. She fills two beakers with equal amounts of hydrogen peroxide. In the first beaker, she adds a small piece of potato at room temperature. In the second beaker, she adds a piece of potato that has been kept in the refrigerator. She observes that the room-temperature potato produces bubbles much faster than the cold one. Determine the Independent and Dependent Variables AND the axis in which they will be graphed.
Independent- Temperature of the potato- y-axis
Dependent- The amount of bubbles produced in the reaction- y-axis.