_URI 101 Chapter 1 condensed.pptx (2)

Matter

Matter is defined as anything that has mass and volume. It is the physical substance that makes up all objects in the universe.

Matter can be classified into two main categories: Pure substances and Mixtures.

A pure substance is a form of matter that cannot be separated into simpler substances by physical means. It maintains consistent properties throughout.
Types of Pure Substances:
- Elements: These are substances that consist of only one type of atom. Examples include hydrogen (H2) and oxygen (O2).
- Compounds: These are substances formed when two or more different elements chemically combine in fixed proportions. They cannot be separated into simpler substances by physical methods. Examples include water (H2O) and sodium chloride (NaCl).

A mixture is a combination of two or more substances that are not chemically combined and can be separated by physical means.
Types of Mixtures:
- Homogeneous Mixtures (Solutions): These have a uniform composition throughout. Example: Copper nitrate solution (Cu(NO3)2), where the solute is uniformly distributed within the solvent.
- Heterogeneous Mixtures: These have a non-uniform composition, meaning that the components can often be seen and separated. Example: Salad dressing, which can have visible oil and vinegar layers.

Filtration: A method used to separate a solid from a liquid in a heterogeneous mixture by passing the mixture through a filter. It exploits the difference in particle size.
Distillation: A process utilized to separate components of a solution based on their boiling points. It is particularly effective for separating homogeneous mixtures. If a mixture is boiled, the liquid with the lower boiling point evaporates, leaving behind the residues.

Matter exists in different states, primarily in three forms: Solid (s), Liquid (l), and Gas (g). Each state has distinct properties:
- Solids: Have a definite shape and volume; particles are closely packed and vibrate in place.
- Liquids: Have a definite volume but take the shape of their container; particles are closely packed but can slide past each other.
- Gases: Have neither a definite shape nor volume; particles are far apart and move freely.

Characteristics used to describe substances fall under several categories:
- Physical Properties: Can be observed without changing the substance’s identity. These include color, phase (solid, liquid, gas), conductivity, and density.
- Intensive Properties: Properties that do not depend on the amount of substance present, such as density and melting point.
- Extensive Properties: These depend on the quantity of matter; examples are mass and volume.
- Chemical Properties: Can only be observed when a substance undergoes a chemical change, indicating its ability to react; an example is the oxidation of copper.

Physical Changes: Changes that affect one or more physical properties of a substance without altering its chemical composition. Examples include changes in state (melting, freezing).
Chemical Changes: Changes that transform substances into new substances with different properties. An example is the combustion of alcohol.

Rules:
- All non-zero digits are significant.
- Interior zeros between non-zero digits are significant.
- Trailing zeros in a number containing a decimal point are significant.
- Leading zeros are not significant.
- In scientific notation, only the digits in the coefficient contribute to significant figures.

For multiplication and division, the result should have the same number of significant figures as the value with the fewest significant figures. For addition and subtraction, the result should retain the least number of decimal places.

Mass: Defined as the quantity of matter in an object; it is a scalar quantity and does not depend on location.
Weight: The force exerted by gravity on an object’s mass; it is dependent on location and varies with the strength of the gravitational field.

Temperature can be measured in three scales: Fahrenheit, Celsius, and Kelvin.
- Water Boiling Points: 212°F, 100°C, 373 K
- Water Freezing Points: 32°F, 0°C, 273 K

Standard Units:
- Length: meters (m)
- Mass: kilograms (kg)
- Volume: liters (L)
- Temperature: Kelvin (K)

Definition: Density is the ratio of mass to volume; it is an intensive property that remains consistent irrespective of the amount.
- Example: The density of water at 25°C is 1 g/mL, which can also be expressed as 1 g/cm³.

Exact Numbers: These comprise counted items or defined values where there is certainty (e.g., 1 kg = 2.205 lbs).
Inexact Numbers: Measurements obtained from experiments are subject to uncertainty. Therefore, understanding and applying significant figures is crucial in reporting these numbers.

Precision: Refers to the degree to which repeated measurements produce the same result; it indicates the reproducibility of results.
Accuracy: Indicates how closely a measured value aligns with the true or accepted value.

To calculate the density of a piece of silver weighing 6.13 × 10^13 picograms (pg), you first convert the mass into grams and then apply the density formula (Density = mass/volume). Given that the density of silver is 10.5 g/cm³, this provides a context for calculation and understanding.

Dimensional Analysis: This systematic method is used to convert units, ensuring that all calculations maintain consistency and correctness in measures.

Proper techniques and consideration of significant figures and unit conversions are fundamental for quantifying and analyzing matter effectively.