Unit: Composition & Properties of Matter Chap 1

Cornell Notes: Objectives Explain matter in terms of both composition and its properties. Using examples, describe matter.

Use cornell notes I will provide the questions for the left hand side Your notes on the right should explain what these questions mean

Composition vs. Properties of Matter Composition = what matter is made of determined by classifying matter The most basic unit of matter is the atom

Properties = what matter is like or how matter behaves Properties are used to describe matter

Describe Matter Any thing that has mass and takes up space Therefore has mass & Volume Is air Matter???

What is Mass? Mass – amount of matter in an object NOT the same thing as weight Is NOT dependent on the location of object Is not affected by gravity Unit: Kg or grams Measure mass using an instrument called a balance

Mass vs. Weight Is a Force Unit: lbs. (english), but Newtons (N)  SI units Is affected by gravity, because is the force of gravity acting on a mass Dependent on location and gravitational force acting there Spring Scale measures weight

How is weight defined?

Converting B/w Mass and Weight Weight = Mass X g W = m g Newtons (N) Kg g = 9.8 m/s 2

variation of acceleration due to gravity on earth Where would you weigh the most?

Problem An object as a mass of 25 kg. What is it weight in Newton’s? W = mg W = 25 kg X 9.8 m/s2 W = 245 N

Problem If an object has a weight of 1500 N, what is its mass? W = mg 1500N = m X 9.8 m/s2 m = kg

Find the mass of an object that has a weight of 950 N. W= m g 950N = 950 kgm/s kg

Converting using pounds (lbs) for units Use Dimensional Analysis using Conversion Factors 1 lb = 4.45 N 1 kg = 2.2 lbs If a guy weighs 195 lbs, what is his weight in Newtons? N

Mass/Weight Conversions A gold bar has a mass of 4 kg. What is its weight in pounds? 8.8 lbs. An box weighs 25 lbs. What is the mass of the box? kg or 1136 grams

What is the mass of 1 ton of asphalt? 1 ton or 1000 kg What is the Weight of 1 ton of asphalt in pounds? 2200 lbs.

What is Volume? The amount of space an object occupies To determine the volume of a substance: Regular Shaped objects: V = Length X Width X Height

For an irregularly shaped object: Use Water displacement

meniscus Water Displacement: Read volume Before adding object Add object Read volume after adding object Volume of Object = difference b/w reading #2 and #1.

Volume Units: Liters, ml 1 ml = 1 cm 3

Density Mass of a substance per unit of Volume it describes the degree of compactness of a substance How much mass is packed into an amount of space

Ratio of mass to volume D = mass Volume units: g/ml or g/cm 3 ***Remember 1 cm 3 = 1 ml

Density Under constant conditions, density remains the same for a substance Since different substances have different densities, density measurements can be used in identifying substances Ex. Density of gold is 19.3 g/ml Density of Water 1 g/ml

Allows for a comparison of different substances (with even different amounts) by putting them on equal ground.

Density will change if substances changes state or phase of matter Solid – Liquid - Gas

How does Temperature Effects Density? Usually the Higher the temperature the Lower the Density.

Water ???

Density Problems What is the density of an object that has a mass of 600 grams and a volume of 350 cm 3 ? 1.71 g/ cm 3 Find the volume of gold that has a mass of 450 grams if the density of gold is 19.3 g/ml ml

Chemical Properties describes its "potential" to undergo some chemical change or reaction by virtue of its composition. Describe the capacity of a substance to undergo a change that will alter the composition of the substance

How do we describe Matter? Describe its properties – Characteristics Physical Properties any property that is measurable and its value describes a physical system's state.propertymeasurablephysical system's can be observed or measured without changing the composition of matter.

Chemical Properties: Describe the capacity of a substance to undergo a change that will alter the composition of the substance Ex. Combustible, Flammable, Able to Rust, Reacts with light, etc.