The Properties of Matter Chapter 2 The Properties of Matter

Section 1 – What is Matter? Vocabulary Matter – Volume – Meniscus – Mass – Gravity – Weight – Newton – Inertia –

What is Matter? Matter is anything that has volume and mass Matter has Volume – all matter takes up space The amount of space taken up by an object is the object’s volume No two things can be in the same space at the same time – even a tiny speck of dust takes up space and no other tiny speck can fit into the space Liquid Volume – measured in Liters (L)

Measuring liquid volume – when we measure liquids in a cylinder the top is not flat it is curved, this curve is the meniscus. This is in all cups but the wider the top the harder it is to see. Measure the lowest part of the scale

Solid Volume – Always expressed in cubic units (3-D), Measured in cubic meters (m3), The 3 shows that three quantities were multiplied to get the result. Length x width x height Solid vs. liquid volume – 1mL = 1cm3 so you can measure an ice cube then measure the liquid is makes Measuring a gas – you have to measure the volume of the container then you know the volume of the gas within

Matter has mass – all matter has mass Mass- the amount of matter that something is made of Mass can only be changed if you increase or decrease the amount of matter something has.

Difference between mass and weight Weight is calculated by the amount of gravitational pull the Earth has on you Gravity is the force of attraction between two objects that is due to their masses, this causes objects to exert pull on other objects. Because everything has mass everything has gravity

Gravity depends on mass (size) and distance Two objects that are large will have greater gravitational force then two small objects. (figure 6 pg 39) Most objects are so small compared to the Earth you don’t see their gravitational force. The Earth is large and therefore has more pull which keeps our atmosphere and us from floating away.

Weight – depending on mass, two objects that are the same size would weigh differently (sponge and brick) sponge has less mass and therefore less pull from the Earth which makes it lighter. As distance grows there is less gravitational force. Things on the Earth would weigh the same everywhere but in space there is less gravitational pull because you are further away so you would weigh less on the moon Weight depends on mass but weight can change mass does not

Measuring mass and weight SI unit of mass is the kilogram (kg) SI unit of weight is Newton (N) because weight is a force (gravity)

Mass is …. A measure of the amount of matter in an object Always constant for an object no matter where it is in the universe Measured with a balance Expressed in kilograms (kg), grams (g), and milligrams(mg) Weight is … A measure of the gravitational force on an object Varies depending on where the thing is in relation to the Earth Measured with a spring scale Expressed in newtons (N)

Inertia Inertia –the tendency of an object to resist any change in motion An object in motion will want to stay in motion and an object at rest will want to stay at rest Mass is a measure of inertia because larger objects are harder to get moving. They are also harder to stop.

Section 2 – Describing Matter Vocabulary Physical property Density Chemical Property Physical Change Chemical Change

Describing Matter Physical Properties – color, odor, mass and volume Table page 44 shows more physical properties Density – mass per unit volume or the amount of matter in a given space To find density first you need to measure mass and volume then use D= Density is the same no matter how big the object is. Assuming it is in the same place. Density is used to identify unknown substances. Water density is 1.00g/cm3 Also tells you what karat of gold you have

Liquid Layers liquid can have different densities and therefore separate from one another It does not matter how much of one liquid you have it will not mix with the bottom layers because the density does not change.

Chemical Properties – describe a substances abilities to change into another substance with different properties (ex wood-ash and smoke) Other examples of chemical properties are flammability, reactivity with oxygen Chemical properties are harder to see but are always there – even when wood is not burning it has the ability to burn Chemicals and cars – Most cars are made of steel (mostly iron) which has lots of good properties but does react to oxygen creating rust

Chemical vs Physical Properties Characteristic properties are those that are always the same no matter much you have. It is what scientists use to identify substances. Remember physical properties you can observe but some chemical properties you can only see when the substance is changing.

Physical Changes don’t form new substances Physical changes affect one of more physical properties of a substance ( example chalk – you can break chalk which would change the size and shape but chalk would still be chalk) Melting, freezing water, sanding wood, bending things, cutting hair

Chemical Changes for New substances Chemical change occurs when one or more substances are changes into new substances. A chemical property means that it has the ability to change whereas a chemical change is the actual process where it changes Examples – soured milk (bacteria has changed the milk), Bake a cake with a bunch of different ingredients and it turns into a cake. Chemical changes are usually signaled by a color change or fizzing, odor, foaming or heat production.

You cannot reverse chemical changes because new substances are formed You cannot reverse chemical changes because new substances are formed. You can’t unmake a cake or unfry an egg. Some can be changed back water formed in the space shuttle rockets can be split back in to hydrogen and oxygen.