genchem1: unit 1 flashcards

atoms

tiny particles, fundamental building blocks of mater

molecules

atoms bind together in specific arrangements to form these

matter

anything that has mass and occupies space

chemistry

science that seeks to understand the behavior of matter by studying atoms and molecules

scientific method

observe, hypothesize, experiment, conclude

hypothesis

tentative interpretation of observation

experiments

controlled procedures designed to generate observations that accept or reject the hypothesis

scientific law

describes what happens; summarizes past and predicts future

scientific theory

explains why or how it happens; a model fro the way nature is and explains why

example of scientific law

matter cannot be created or destroyed

example of scientific theory

the atomic theory explained the law of conservation of mass by proposing that matter is
composed atoms rearranged in
chemical changes

What are the two ways that matter can be classified?

state and composition

What are examples of state for classifying matter?

solid, liquid, gas

What are examples of composition for classifying matter?

pure substance (element or compound) or mixture (heterogeneous or homogeneous)

describe solids

-packed closely

-fixed locations

-vibrate only

-fixed volume

-rigid shape

describe liquids

-packed closely

-move freely

-fixed volume

-shape of container

describe gases

-lots of space between

-move freely

-volume of container

-shape of containerH

How are solids and liquids similar?

particles packed closely and fixed volume

How are liquids and gases similar?

move freely and shape of container

How are solids different from liquids and gases?

particles fixed in place, vibrate only, rigid shape

How are liquids different from solids and gases?

particles packed closely but can move, shape of container, not rigid

How are gases different from liquids and solids?

particles far apart, move freely, expand to fill volume and shape of container

pure substance

1 component; same each sample

element

cannot be chemically broken down/ be simpler

compound

2+ elements in fixed proportions; can be simpler

mixture

2+ components; varies between samples

heterogeneous mixture

composition varies by region

homogeneous mixture

same composition all the way throughout

chemical changes

change in composition; atoms rearrange to a new substance

example of chemical changes

iron rusting

physical changes

change in state or appearance; same atoms or molecules

example of physical changes

water boils

chemical properties

displayed only by changing composition via chemical change

examples of chemical properties

corrosiveness, flammability, acidity, toxicity

physical properties

displayed without changing composition

examples of physical properties

odor, taste, color, density, appearance, melting point, boiling point

energy

capacity to do work

work

action of force through a distance

potential energy (PE)

associated with position or composition

kinetic energy (KE)

associated with motion

chemical energy

a type of PE; associated with chemical bonds of a molecule

thermal energy

a type of KE; associated with temperature

total energy

KE + PE

law of conservation of energy

energy is not created or destroyed; can flow from one object to another, but total energy does not change

important point about the conservation of energy and the preference of systems

systems with high PE are unstable, so they tend to change in the direction of lower PE, releasing energy into the surroundings

unit and symbol for length

meter, m

unit and symbol for mass

kilogram, kg

unit and symbol for time

second, s

unit and symbol for temperature

kelvin, k

unit and symbol for amount of substance

mole, mol

unit and symbol for electrical current

ampere, A

kilogram (kg)

measure of mass

mass

measure of quantity of matter

weight

measure of gravitational pull

Kelvin (K)

measure of temperature (average KE of atoms or molecules)

use of kelvin scale

avoids negative temperatures

thermal energy

heat

example of thermal energy

holding an ice cube: heat flows from the hand to the cube

Kelvin formula

C + 273.15

Celsius formula

(F - 32) / 1.8

correct form of scientific notation

coefficient (between 1 and 10) x 10^power

kilo

k, 1000, 10³

deci

d, 0.1, 10^-1

centi

c, 0.01, 10^-2

mili

m, 0.001, 10^-3

micro

μ, 0.000001, 10^-6

nano

n, 0.000000001, 10^-9

pico

p, 0.000000000001, 10^-12

derived units

combination of other units

speed

m/s

volume

L or mL or mm3 cm3 or m3

density

g/cm3 or g/mL or kg/m3

density formula

d= m/v

intensive property

independent of the amount of substance

example of intensive property

density

extensive property

dependent on the amount of substance

example of extensive property

mass

How can the mass of solids and liquids be measured?

analytical balance

If a solid is oddly shaped, how can the volume be measured by?

displacement of liquid

How are are scientific measurements reported?

every digit is certain except the last onewhich is estimated. This reflects the precision and accuracy of the measurement.

What is accuracy?

how close a measured value is to the actual value; It indicates the correctness of a measurement.

What is precision?

consistency and reproducibility of repeated measurements, indicating how closely grouped the values are to each other.

What is a systematic error?

A consistent, repeatable error that occurs in the same direction, affecting the accuracy of measurements; can arise from faulty equipment, poor calibration, or bias in the measurement process.

What is a random error?

An error that occurs unpredictably and varies in magnitude or direction, affecting the precision of measurements; can be caused by uncontrolled variables or fluctuations in measurement conditions.

What are significant figures?

Digits in a number that carry meaningful information about its precision; more sig figs = more certainty in measurement

All non-___ are significant

zero digits are significant

Interior zeroes are ___

significant when they are between non-zero digits.

Leading zeroes ___ significant

are not

Trailing zeroes after the decimal point ___ significant

are significant

Trailing zeroes before the decimal point ___ significant

are significant

Sig fig rules for multiplication and division

The result should have the same number of significant figures as the measurement with the least number of significant figures.

Sig fig rules with addition and subtraction

The result should have the same number of decimal places as the measurement with the least number of decimal places.

What is dimensional analysis?

a mathematical technique used to convert units from one system to another, ensuring that the final answer has the correct units.

What is a conversion factor?

a ratio of equivalent measurements that can be used to change units; are exact numbers that do not impact significant figures

What type of conversion factors matter for sig figs?

Only measured quantities affect significant figures, not exact numbers.

What three laws led to the development of modern atomic theory?

The Law of Conservation of Mass, the Law of Definite Proportions, and the Law of Multiple Proportions.

What is the law of conservation of mass?

mass is neither created nor destroyed; in a chemical reaction, particles rearrange but the total mass of reactants equals the total mass of products.

What is the law of definite proportions?

In a chemical compound, the elements are always combined in the same proportion by mass, regardless of the size or source of the compound. This means that a given compound contains the same elements in the same mass ratio, ensuring consistency in chemical composition.

What is the law of multiple proportions?

When two elements form multiple compounds, the ratios of the masses of one element that combine with a fixed mass of the other can be expressed as small whole numbers.

Law of definite proportion example: 1. has 25.6 g O and 9.6 g C and 2. has 21.6 g O and 8.1 g C

shows that the ratio of O to C is consistent across compounds
(25.6/9.6 =2.667 and 21.6/8.1=2.667)