Chapter 1 Flashcards
summarize the steps of the scientific method
- carefully define the problem
- perform experiments
- make observations
- record information or data about the system (data will either be qualitative or quantitative)
- interpretation
- hypothesis
- more experiments are made to test the hypothesis, and the process begins again
what is the scientific method?
the scientific method is a systematic approach to research
what is the difference between qualitative and quantitative data?
-Qualitative data consists of general observations about the system. (describes the observation).
-Quantitative data comprises numbers obtained by various measurements of the system. (how much?).
scientific knowledge is empirical. what does this mean?
Empirical means that is is based on observation and experiment. (scientists observe and perform experiments on the physical world to learn about it)
chemistry is the science that seeks to understand _____
chemistry is the science that seeks to understand the behavior of matter by studying the behavior of atoms and molecules.
chemistry observes ____
chemistry observes the changes that matter undergoes and measures the amount of energy produced or consumed during those changes
the scientific approach to knowledge consists of what three things?
Laws, theories, and observations
what is a law?
A law is a concise verbal or mathematical statement of a relationship between phenomena that is always under the same conditions. Laws are proven to be correct, they always stay the same and are constants.
what is a theory?
A theory is a unifying principle that explains a body of facts and/or those laws that are based on them. Theories aren’t proven correct and aren’t constant. The part of theories that change is the “why”.
what two things can an observation lead to?
observation either leads to a law or hypothesis. both the law and hypothesis have to be tested. the hypothesis can lead to a theory, which also gets tested.
all things that are physically real (air we breathe, sunshine, the ground) are forms of either _____ or _____
all things that are physically real (air we breathe, sunshine, the ground) are forms of either matter or energy.
what is matter?
Matter is anything that has mass and occupies space.
A specific instance of matter is called a _____
A specific instance of matter is called a substance
what two things are matter classified by?
Matter is classified by its state (whether its solid, liquid, or gas) and composition (the kinds and amounts of substances that compose it)
define mass
mass is the property that defines the quantities of matter in an object
define a substance
a substance is a form of matter that has a definite (constant) composition and distinct properties
what can substances be identified by?
substances can be identified by its appearance, smell, taste, and other properties.
what is energy?
energy is the capacity to transfer heat or do work. we want chemical reactions to transfer heat or do work.
what are two types of matter?
- Mixture
- Pure substance
what is a mixture?
a mixture is a substance composed of two or more substances in which the substances retain their distinct identities that can be combined in continuously variable proportions
what states of matter can mixtures be in?
solid, liquid, or gas
do samples of mixtures have the same physical and chemical characteristics?
samples of the substance of the mixture may not have the same physical and chemical characteristics.
mixtures can either be _____ or ______
mixtures can either be heterogenous or homogenous
what is a heterogenous mixture?
- A heterogeneous mixture is a substance whose composition is NOT uniform.
- substances AREN’T mixed uniformly.
- regions within the sample can have DIFFERENT chemical and physical characteristics
what is a homogenous mixture?
- a homogenous mixture is a substance in which the composition of the mixture is the SAME throughout.
- substances ARE mixed uniformly.
- regions within the sample can have the SAME chemical and physical characteristics - no matter where you test, it will all have the same chemical and physical characteristics.
what is the second type of matter - a pure substance?
a pure substance is a substance composed of only a single type of atom or molecule
what states of matter can a pure substance be in?
solid, liquid, or gas
do samples of pure substances have the same physical and chemical characteristics?
yes, all samples of a pure substance have the same physical and chemical characteristics
what are the two types of pure substances?
the two types of pure substances are element and compound
what is an element?
an element is a substance that cannot be separated further into simpler substances by chemical methods
what are the characteristics of elements?
-they are the basic building blocks of matter
-they are composed of a single type of atom
-they are rare in nature
-can be solid, liquid, or gas
what is a compound?
a compound is a substance composed of atoms of two or more elements chemically united in fixed proportions
what are the characteristics of a compound?
-they are the most common pure substance.
- they can be solid, liquid, or gas
- most things we interact with are compounds
can compounds be broken down into elements? how?
yes, compounds can be broken down into elements by chemical reaction (not just a magnet)
what are the three states of matter?
solid, liquid, and gas
in solid matter, how are the atoms and molecules packed?
in solid matter, atoms or molecules are packed closely to each other in fixed locations.
can the atoms or molecules in solid matter vibrate? can they move around or past each other?
Yes, the atoms and molecules in solid matter CAN vibrate, but they DO NOT move around or past each other
on an atomic level of solid matter, can the molecules get any closer, and is there volume between each molecule?
on an atomic level of solid matter, the molecules CANNOT get any closer, and there is NO volume between each molecule
What are the volume and shape of a solid?
solid matter has a FIXED volume and RIGID shape
are solids compressible?
no, solids are incompressible
what are the two different types of solids?
- Crystalline solid: regularly ordered structure with repeating pattern.
- Amorphous solid: no long-range order with no repatting pattern.
in liquid matter, how are the atoms/molecules packed, and can they move?
in liquid matter, atoms or molecules are packed closely to each other, BUT are free to move relative to each other
what are the volume and shape of a liquid?
liquid matter has a FIXED volume but NOT a fixed shape - it assumes the shape of the container
is liquid matter compressible?
liquid matter is somewhat compressible - since there is more space between liquid molecules