Unit: Properties of Matter Chap 15 &16

What is Physical Science? Study of Chemistry and Physics Not a life Science Class

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

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. can be observed or measured without changing the composition of matter.

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

Physical Properties: Mass – amount of matter in an object Is a property of a substance Is not dependent on the location of object Is not affected by gravity Unit: Kg or grams Triple Beam Balance

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

FYI 1 stone = 14 pounds

Does a person’s weight change with altitude?

What is gravity? is a natural phenomenon by which physical bodies attract each other with a force proportional to their masses. In 1687, English mathematician Sir Isaac Newton published Principia, which hypothesizes the inverse-square law of universal gravitation.

What does the size of Gravity depend on? Mass of 2 objects Distance between their Centers (called center of gravity)

How is weight defined?

Converting B/w Mass and Weight Weight = Mass X g W = m g Kg Newtons (N) g = 9.8 m/s2

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

gravitational accelerations

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 = 153.06 kg

Find the mass of an object that has a weight of 950 N. W= m g 950N = 950 kgm/s2 96.94 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? 867.75 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? 11.36 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.

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

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

Volume Units: Liters, ml 1 ml = 1 cm3

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/cm3 ***Remember 1 cm3 = 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 cm3? 1.71 g/ cm3 Find the volume of gold that has a mass of 450 grams if the density of gold is 19.3 g/ml. 23.3 ml

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.