Introduction: Matter and Measurement Flashcards

This flashcard set covers the basic concepts of matter classification, physical states, properties of substances, SI units, and the principles of measurement uncertainty as described in the lecture notes.

Matter

Anything that has mass and takes up space.

Gas (vapour)

A state of matter that has no fixed shape or volume; its molecules are far apart and move at high speeds, colliding with each other.

Liquid

A state of matter that has a distinct volume but no fixed shape; its molecules are packed closely together but move rapidly.

Solid

A state of matter that has a definite shape and volume; its molecules are held tightly together.

Mixture

Matter that contains various substances mixed together and can be separated by physical means into its components.

Physical means

Methods that use differences in physical properties for separation, such as distillation using differences in boiling point.

Homogeneous mixture

A mixture that is uniform throughout, even at a microscopic level; it is also called a solution.

Heterogeneous mixture

A mixture that is not uniform throughout, such as a suspension.

Substance

A single pure form of matter that cannot be separated by physical means and has a set of distinct properties.

Element

A substance composed of only one kind of atom which cannot be separated further by chemical means.

Chemical means

Methods that use chemical reactivity to decompose a substance, such as electrolysis.

Compound

A substance containing different kinds of atoms made of two or more elements; it can be decomposed into simpler compounds or constituent elements by chemical means.

Atom

The smallest particle of an element.

Molecule

A particle consisting of two or more atoms, of the same or different elements, chemically bound together.

Giant lattice

A huge regular arrangement of atoms found in elements like carbon, silicon, and metals.

Chemical symbol

A unique 1 or 2 letter code for an element where the first letter is always a capital and the second letter is always a small letter.

Law of Constant Composition

A principle stating that a compound consists of two or more elements in a definite mass ratio.

Chemical formula

A representation showing the number and kind of element(s) present in the basic particle of a substance, such as $H_2$ or $CO_2$.

Physical properties

Characteristics observed without changing the chemical identity of a substance, such as melting point.

Chemical properties

Characteristics observed by changing the chemical identity of a substance, concerning its chemical reactions like reactivity with oxygen.

Physical change

A change of state of a substance.

Chemical change

The reaction of one substance to give another substance or substances.

Intensive properties

Properties that do not depend on the amount of substance, used to identify a substance, such as density or colour.

Extensive properties

Properties that depend on the amount of substance present, such as volume or mass.

SI Units

A system of units used in science based on the metric system, including base units such as kilogram ($kg$), metre ($m$), second ($s$), Kelvin ($K$), and mole ($mol$).

Prefixes

Additions to units used to indicate decimal fractions or multiples, such as pico ($10^{-12}$), nano ($10^{-9}$), and kilo ($10^3$).

Absolute zero

The temperature of $0\,K$, which is equal to $-273.15^\circ C$.

Density ($d$)

The mass ($m$) per unit volume ($V$) of a substance, expressed as $d = \frac{m}{V}$.

Exact numbers

Numbers whose values are exactly known, such as counted numbers or numbers in definitions.

Inexact numbers

Numbers that have an uncertainty, including measured values or calculations based on measured values.

Significant figures

Digits reported in a measurement where only the last digit is uncertain and all preceding digits are certain.

Precision

The agreement between multiple measurements, determined by the spread in results.

Accuracy

The agreement of a measurement or average value with the true or accepted value.