The Properties of Matter Chapter 2 The Properties of Matter

Section 1 What is matter?

Matter is anything that has mass and takes up space. Volume is the amount of space taken up or occupied by an object. All matter has volume

Volume of a regularly shaped solid object Expressed in cubic units The word cubic means having 3-dimensions Units most often expressed in cubic meters (m3) or cubic centimeters (cm3) Formula: Volume = length x width x height

Liquid volume: Liters and milliliters are the units typically used to express the volume of liquids The tool used to measure liquid volume in science is the graduated cylinder The meniscus is the curve at a liquid’s surface by which one measures the volume of the liquid.

Volume of an irregularly shaped solid object Cannot use simple equation Measure using the displacement method. Measure how much water the object displaces. Because 1 mL = 1 cm3, you can express the volume in cm3

Matter and Mass A second characteristic of all matter is mass Mass is the amount of matter in an object The mass of an object stays the same no matter where the object is at in the universe.

Difference between mass and weight They do not mean the same thing Mass is the amount of matter in an object Weight is a measure of the gravitational force exerted on an object Value can change with the location of the object in the universe

For example…

Measuring mass and weight Weight is a measure of gravitational force Expressed in the SI unit of force, the Newton (N) 1 Newton = the weight of an object that has a mass of 100 grams on Earth

Inertia Inertia is the tendency of an object to resist being moved or, if the object is moving, to resist a change in speed or direction until acted on by an outside force Mass is the measure of inertia Large mass = harder to move and harder to stop

A student has a mass of 45,000 g. How much does this student weigh in Newtons?

Section 2 Physical Properties

What are physical properties? Characteristics of a substance that does not involve a chemical change, such as density, color, or hardness Some examples of physical properties are… Thermal conductivity State Density Solubility Ductility Malleability See page 45

Identifying physical properties… Physical properties are identified through observation using the five senses

Physical Changes Do Not Form New Substances A physical change is a change of matter from one form to another without a change in chemical properties. Examples…

What is Density? Density is a physical property that describes the relationship between mass and volume. Density is the amount of matter in a given volume. https://www.youtube.com/watch?v=eJKM4w7mFrk

Density and liquid layers Each type of liquid has a different density Most dense liquid is at the bottom Least dense liquid is at the top

Density of solids 1 kg of lead vs. 1 kg of feathers Which do you want to carry around all day? Both the feathers and the lead have the same mass However the feathers are much less dense than lead, so it takes a lot of feathers to equal the same mass as lead Density of Water (H2O) = 1.00 g/mL Density of object > density of water Object sinks Density of object < density of water Object floats

Solving for Density 1st measure the objects mass (m) 2nd measure the objects volume (V) Then, use this equation: D = m/V Units are typically expressed in g/cm3 (solids) g/mL (liquids)

Example density problems… What is the density of an object whose mass is 25 g and whose volume is 10 cm3 D = 2.5 g/cm3 Suppose you have a lead ball, with a volume of 40 cm3 and a mass of 454 g. What is the ball’s density? D = 11.35 g/cm3 Homework: p.49; 2-11

1. ) Please lay your Ch 2 vocab cards on your desk, definition side up 1.) Please lay your Ch 2 vocab cards on your desk, definition side up. 2.) Take a few minutes and think about your personal goals.

In your science binder, write down a goal you're striving for this week.

Section 3 Chemical Properties

Chemical Properties a property of matter that describes a substance’s ability to participate in chemical reactions Examples: Flammability: gasoline, rubbing alcohol, wood Reactivity: Acetic Acid and baking soda, sodium metal and water https://www.youtube.com/watch?v=NTFBXJ3Zd_4

Comparing physical and chemical properties What can we do with a pencil? Break it!!!!!!!!!!!!!! = Physical change Burn it!!!!!!!!!!!!! = Chemical change

Chemical changes and new substances A chemical change occurs when one or more substances change into entirely new substances with different properties Examples: Every time a battery is used, if reaction fails you have a dead battery Digestion of food

Physical vs. Chemical changes Does the composition change? The composition of an object is the type of matter that makes up the object and the way the matter is arranged in the object. For example: Electrolysis

Reversing changes Physical changes Easily reversed because composition does not change i.e. Ice cube melts---Refreeze Chemical changes Difficult to reverse because composition does change i.e. fireworks

In your science journals: 1. ) Are all golf balls created equal In your science journals: 1.) Are all golf balls created equal?  Calculate the density and weight of each golf ball. Assuming I apply the same force with a driver and all external conditions remain constant, will each ball go the same distance.   2.) Calculate the density and weight of the wood block.  Prove it will float in water?