Chapter 1 Flashcards
What is Chemistry?
It is the study of properties and behavior of matter.
What is matter?
Matter is anything that has mass and takes up space.
The properties of atoms and molecules…
…Distinguish one type of matter from the other.
Atoms
Are submicroscopic particles that are the fundamental building blocks of ordinary matter. Free atoms are rare in nature; more commonly they bind together in specific arrangements to form a molecule.
The 116 different types of atoms are called…
Elements
Classification of matter depends on…
…its state and composition.
Solid
Has a fixed shape and volume; may be crystalline (organized in patterns with long-range) or amorphous (no long-range order)
Liquid
Fixed volume but no fixed shape. Atoms are as closely bound as solid matter, but they are more free to move. They tend to assume the shape of their container.
Gas
Neither its volume or shape are fixed. Sample take these properties from the gas’ container.
Increasing of temperature leads to a…
…change in the state of matter.
Pure substances vs. Mixture
If a certain type of matter has uniformity throughout its composition, then it is called homogeneous. Homogeneous substances can have a variable composition, being called homogeneous mixtures or if they don’t, they are called pure substances. Pure substances can be separated into simpler substances and are called compounds, or are not breakable into smaller substances are called elements. Now, if it is not uniform, matter is classified as heterogeneous.
Heterogeneous vs Homogeneous
Heterogeneous mixtures do not have an uniform composition of particles and will often separate into its constituent parts; homogeneous mixtures have a uniform composition of constituent particles down to a microscopic level and do not separate into its constituent parts. Basically, if there is no difference on the molecular level, then it is homogeneous. If the difference is more on the cellular level, then it’s heterogeneous.
What are the three main processes for separating mixtures?
Decanting, distillation, and filtration.
Physical changes
They only alter the state and appearance of the matter, but not is composition, which means that the atoms and molecules do not change. It results in a different form of the same substance. Some examples are: odor, taste, color, appearance, melting point, boiling point.
Chemical changes
Leads to atoms getting rearranged, transforming that substance into something different. Some examples are: Acidity, toxicity, flammability, corrosiveness, etc.
Physical and chemical changes are…
…representations of physical and chemical properties.
Properties of a compound are always the same properties of its elements.
False. The properties of a compound can differ greatly from the properties of the elements that are part of it.
It states that a sample of pure matter will always have the same elemental composition, regarding of its source.
Law of Constant Composition or Law of Definite Composition
Intensive properties
Do not depend on the amount of the substance, such as temperature, color, and density. Also called qualitative, help identifying such substances.
Extensive properties
Depend on the amount of substance. These include mass, weight, and volume. They are also called quantitative.
Energy
Capacity to do work
Work
The action of a force through distance
Kinetic energy
Regarding a certain object’s motion
Potential energy
Energy associated with a certain object’s position or composition. Usually objects with a high rate of potential energy tend to be unstable.
Thermal energy
Associated with the temperature of an object. It is considered a type of kinetic energy because it arises from the motion of individual atoms or molecules.
Mass
Kilogram (Kg)
Length
Meter (m)
Second (s)
Time
Kelvin (K)
Temperature
Amount of substance
Mole (mol)
Ampere (A)
Electric current
Candela (Cd)
Luminous intensity
All the temperature scales are called absolute scales
False. Only the Kelvin scale is also known as the absolute scale, as it is the only one that does not allow negative temperatures.
Absolute zero is…
…the temperature at which molecular motion virtually stops.
Mass vs. weight
Mass is the quantity of matter within it, while the weight is the measure of the gravitational pull on a certain object’s matter.
Derived units
Combination of other units in order to create a new one.
Precision vs. Accuracy
Precision is how well repeated measurements agree with each other, while accuracy is how well measurement agree with the correct value.
Potential energy decreases
as kinetic energy increases
Law of Conservation of Energy
States that energy is nor created or destroyed
Systems with high potential energy tend to change in a direction…
…That lowers their potential energy, releasing it into the surroundings.
