Chapter 1Chemistry is the science that deals with matter. The structure and properties of matter and the transformations from one form to another.Matter is anything that has mass and takes up space. Matter can change from one form to another.

Chemical Change aka a chemical reaction, substances are used up others are formed to take their places. i.e. bottled gas.

Physical Change The identities of substances do not change; mostly changes of state. i.e. melting of solids or the boiling of liquids. Another important physical change is the mixing or separating of liquids- i.e. dissolving sugar in water.

Chemical properties: the reaction that a substance undergoes.Physical properties: all the properties that do not include chemical reactions. i.e. density, color, melting point, and physical state (liquid, solid, gas).

Scientific Method: scientific tool; tests theories. Fact: statement based on direct experience. It is a consistent and reproducible observation. i.e.

Galen observed that the blood from the left side of the heart somehow moves to the right. Based on this, he formed an a hypothesis to explain this.

Hypothesis: statement that is proposed, without actual proof, to explain the facts and their relationship. Galen proposed there tiny holes present in muscular wall that separates two halves.

Theory: When a hypothesis passes the test, we have more confidence and call it a theory. It is the formulation of an apparent relationship among certain phenomena, which has been verified to some extent. If new facts show that the theory is wrong, it’s rejected or altered later on.

(Some scientific discoveries result from serendipity, chance observation)

How Scientists Report Numbers: Exponential Notation, Significant Figures, Metric System, Measurements.

Also, if presented with scientific notation, the actual number given (aside from the power) IS the amount of significant figures.

Measurement: consists of two parts- unit and number.Metric System: A system of units of measurement in which the divisions to subunits are made by a power of 10.Length: Meter is the base unit.Volume: is space. The volume of liquid, solid or gas is the space occupied by that substance. Liter is the base unit.Mass: Quantity of matter in an object. Gram is the base unit. The difference between mass and weight, although often used interchangeably, is that mass is independent of location, but weight is not. Gravity impacts weight. So while one’s mass will be the same here and on the moon, one’s weight will differ in these locations.

Basic units of metric system:Length- MeterVolume- LiterMass- GramTemperature- KelvinTime- SecondEnergy- Joule

Time: one quantity which is the same across all units. 60s= minute, 60 minutes/hour.Temperature: We’re used to using Fahrenheit, but the metric system utilizes Celsius. The boiling point in Celsius is 100 degrees, the melting point is 0 degrees. Kelvin is similar to Celsius, so it’s easy to convert between the two units. The size of a Kelvin degree is the same as the size of a Celsius degree. The Kelvin scale, however, uses -273C as the zero point because it’s the lowest possible temperature. It translates to 0K and is referred to as an absolute zero. Temperature reflects how fast molecules move; the more slowly they move, the colder it gets. At absolute zero, molecules stop moving altogether, so the temperature can’t get any lower. Kelvin scale fulfils the importance of having a scale that starts at the lowest possible temperature.

Factor Label MethodConversion Units

States of Matter: Whether a substance is a gas, liquid or solid depends on temperature and pressure (i.e. a puddle of water turns to ice on a cold day). Most substances can exist in all three states; gases at high temperature (i.e. boiling water steam), liquid in lower temperature, and solids when temperature becomes low enough. * The chemical identity of a substance does NOT change when it is converted from one state to another.

Gas: No definite shape or volume, expand to fill whatever container they are put into, but they are highly compressible and can be forced into small containers.

Liquid: Have no definite shape, slightly compressible, but they do have a definite volume that remains the same when poured from one container to another.

Solid: Definite shape, definite volume, essentially incompressible

Density: Density of a substance is defined as its mass per unit volume. Not only do all liquids have density, but so do all solids and gasses. When two liquids are mixed (and one doesn’t dissolve in the other), the one with the lower density floats to the top (oil and water). The density of any liquid or solid is a constant physical property, which means it always has the same value at a given temperature. Almost always, we use physical properties to help identify a substance. However, density DOES change when temperature does; almost always density decreases with increasing temperature. This is true because mass doesn’t change when a substance is heated, but volume almost always increase because atoms and molecules tend to get farther apart as temperature increases. Since D= m/v, if mass stays the same and V gets larger, D must get smaller. Water, the most common liquid, provides an exception to this rule. As the temperature of water increases from 4 degrees Celsius to 100 degrees Celsius, the density of water does decrease, but from an increase of temperature of zero Celsius degrees to 4 Celsius, the density increases.

Specific Gravity: Numerically the same as density, but with no units (density always has units, like g/ML). The reason why there are no units is because specific gravity is defined as a comparison of the density of a substance with the density of water, which is taken as a standard. Specific gravity is almost always equal to density. Specific gravity is measured by a hydrometer (or urinometer for testing urine). Patients with diabetes have abnormally high specific gravity of urine whereas patients with kidney disease have abnormally low specific gravity.

Energy: the capacity to do work. Kinetic Energy: Energy of motion. Any moving object possesses kinetic energy. Kinetic energy

increases when an object moves faster or when a heavier object is moving. When a truck and bicycle are moving at the same velocity, the truck has more kinetic energy. Formula: KE= ½ mv^2

o Mechanical energy, light, heat and electrical energy , which are possessed by all moving objects from elephants to molecules or electrons.

Potential Energy: Stored energy. It is converted into kinetic when doing work, with help from gravity. In nature, things have a tendency to seek their lowest possible potential energy; water flows downhill not uphill.

o Chemical Energy and Nuclear Energy: the most common form of potential energy in chemistry is chemical energy, the energy stored within chemical substances and given off when they take part in a chemical reaction.

The Various forms of energy can be converted from one form to another, but the total amount of energy in any system does not change. Energy can neither be created or destroyed, which is the law of conservation of energy .

Heat and temperature: one of the most important forms of energy in chemistry; it frequently accompanies chemical reactions. NOT the same as temperature. Heat is a form of energy, temperature is not. The difference is the follows: there is one beaker with 100 ML of boiling water and another with 1 Liter of boiling water; both at the same temperature, but the one with 100 ML is LESS likely to burn you than the 1 Liter, because the 1 Liter of water has more heat (even though at same temperature). Heat is measured in calories, which is the amount of heat necessary to raise the temperature of 1 g of liquid water to 1 degree Celsius. It’s a small unit and chemists often use kilocalorie. 1 k calorie= 1,000 calories. Nutritionists use Calorie with a capital C to mean the same thing as kilocalorie, so Calorie= 1,000 calories. The calorie is not part of the SI. The SI unit for heat is joule, which is ¼ as big as a calorie. 1 calorie= 4.184 J.

Specific Heat: The amount of heat necessary to raise the temperature of 1 g of any substance by 1 degree Celsius. Each substance has its own specific heat (which is a physical property). Calculation formula:Amount of Heat= specific heat x mass x change in temperature So: SH x m x (T2- T1) where T2 is the final temperature and T1 is the initial temperature in Celsius.

Chapter 2What is matter made of?

Democritus: believed all matter was made of small particles impossible to see, called atoms. Followers believed there were different kinds of atoms with different properties.

Zeno of Elea: Rejected the idea of atoms. Insisted matter is infinitely divisible. So you could never reach a particle that wasn’t divisible.

Today we know Zeno of Elea was wrong and Democritus was right, but our ideas, unlike Democritus, are based on evidence.

o Atoms are basic units of matter

Matter: divided into 2 classes: pure substances and mixtures, which both are then further subdivided.Pure substances: fixed composition; can’t be further purified.

Element : substance that consists of identical atoms. 116 elements known today; only 88 occur in nature, the rest have been made in the lab.

Compound : elements united in fixed ratios. (Chemically combined elements). A pure substance made up of two or more elements in a fixed ratio by mass. i.e. water. 20 million compounds known today.

Mixtures: a combination of two or more pure substances. Most of daily matter we encounter in our daily lives are mixtures rather than pure substances.