Chemistry Chapter 1 -2

What is Matter  Matter:  Anything that has mass and volume  Ex:  Air we breathe  When we blow up a balloon it has more mass and a greater volume than when it was deflated

What is Matter?  Volume:  Space that an object occupies  Ex:  Textbook – It takes up space  How do we measure the volume of a liquid?  Must be read the same way EVERY time!

What is Matter?  Mass:  Quantity of matter in an object  How do we measure mass?  Electronic balance  Triple beam balance’  Mass is related but not identical to weight

What is Matter?  Weight:  Force produced by gravity acing on mass  The weight of an object depends on where it is. Whereas the mass of an object will always be the same no matter where it is in the universe.  Ex: An astronaut weighs about 6 times more on Earth than on the moon because the effect of gravity is less on the moon. His mass though remains constant!

Units of Measurement  In class we will use quantitative terms – numbers – to make descriptions more accurate.  Ex. 15 grams of sugar instead of a spoonful  Quantity:  Has magnitude or size  Unit:  Standard used when measuring a quanity

Units of Measurement  Ex. You can measure the quantity mass with the unit kilogram.  What quantity is measured with the unit meters?

Units of Measurement  In 1960 the standard system of measurement units was adopted  There are 7 base units which you can find in Table 1-3 on page 12

=636&tbm=isch&tbnid=030msR9OwdMqUM:&imgrefurl= blb9ch0104.html&docid=0QUZV7zv- sePeM&imgurl= dQULuOEITWyQGBqIAY&zoom=1&iact=hc&vpx=637&vpy=166&dur=4310&hovh=160&hovw=316&tx=204&ty= 72&sig= &page=1&tbnh=93&tbnw=183&start=0&ndsp=15&ved=1t:429,r:4,s:0,i:87

Units of Measurement  We will be converting from 1 unit to another  Conversion Factor:  Mathematical expression that relates two units  Ex: Convert 1.5 kg to grams

Units of Measurement  Derived units:  Created from combinations of the base SI units  Volume  Multiple length, width, and the height of an object  m x m x m = m^3  Make sure when converting to do it 3 times to end up in m^3

Units of Measurement  1000 cm^3  m^3  mm^3  All of these equal 1 L

Properties of Matter  Relationships between properties can be represented by graphing  When you look at the graph on page 15 what do you notice?  The mass of the aluminum is directly proportional to its volume

Properties of Matter  The slope of the line equals the ratio of mass  Slope = y2 – y1/ x2 – x1  Density:  Ratio of mass to volume  Density = mass / volume

Density  Unit for density is g/cm^3  Look at Figure 1-11  Which substances have a density of less than 1 and how do you know?  We can also use density to figure out mass or volume  D X V = m  m / D = V

Density  If you found a bracelet on the street and you wanted to find out if it was made of real silver what would be your first step?  Mass = g  Volume = 20.5 cm^3  D = m / V  g / 20.5 cm^3 = 9.71 g/cm^3  Look at Table 1-5 to find the density of silver and determine if the bracelet is actually made of silver

Physical Properties  Physical Property:  Any property of matter that can be measured without changing its chemical nature.  Ex: Mass, volume, and density  Ex: Color, texture, melting point, and boiling point

Physical Properties  Physical Changes:  Change that affects only the physical properties  Ex: Melt water to get ice  you still have H2O  Ex: Boil water to get steam

Physical Changes  Physical changes can involve changes in energy  Melting & Boiling are endothermic changes because heat is transferred to the substance from the surroundings  Freezing & Condensation are exothermic changes because heat is transferred from the substance to its surroundings.

Chemical Properties  Chemical Property:  Property of matter that can be observed only when substances interact with one another.  Chemical Change:  A change that produces one or more new substances.

Chemical Properties  Evidence a chemical change has occurred. 1.The evolution of a gas- we can see gas bubbling or the emission of an odor. 2.Formation of a precipitate – insoluble solid 3.Evolution or absorption of heat – increase or decrease in temperature

Chemical Properties 4. The emission of light – light is produced 5. Color change – look at Figure 1-13 letter d. This shows the color change of an indicator in the presence of a base.