CHEM 200 Exam 1 Units 1-3 Vocabulary Flashcards

Vocabulary practice flashcards generated from Units 1-3 of CHEM 200, covering core definitions for measurement, classification of matter, nuclear chemistry, bonding, VSEPR, and stoichiometry.

Pure substance

A form of matter with one fixed composition and one chemical symbol or formula that cannot be separated by physical methods (H2O, NaCl, HE, Fe).

Element

A pure substance consisting of only one type of atom, represented by a single element symbol (O2, Cu)

Compound

A pure substance composed of two or more elements chemically joined in a fixed ratio, with a formula containing two or more element symbols (CO2, KCI, H2O).

Homogeneous mixture

A physical blend that is uniform throughout and exists as one visible phase, so every sample has the same composition (mouthwash, unopened cola, oil).

Heterogeneous mixture

A physical blend that is nonuniform throughout, containing distinct regions or phases with varying sample compositions (soup, salad, icecream)

Physical property

A characteristic of a substance that can be observed or measured without changing its chemical identity (color; density; melting point; state).

Physical change

A change in form or state of matter where particles retain their original chemical identity (melting, bending, dissolving, mixing colors).

Chemical property

The ability of a substance to undergo a specific chemical change to form new substances (flammability, reactivity).

Chemical reaction

A process in which atoms rearrange to form new substances with different chemical properties (gas formation from reaction, precipitate, sustained color/temperature change, burning/rusting).

Density

The mass per unit volume of a substance, defined by the formula $d = \frac{m}{V}$ and commonly expressed in units of $g/mL$.

Specific gravity

A unitless ratio comparing the density of a substance to the density of water.

Potential energy

Stored energy due to the position or chemical composition of a substance.

Kinetic energy

The energy possessed by an object or particle due to its motion.

Specific heat

The quantity of heat required to raise the temperature of $1\,g$ of a substance by $1\,^\circ C$.

Accuracy

The closeness of a single measurement or average measurement to the true or accepted value.

Precision

The closeness of repeated measurements or values to one another.

Atomic number ($Z$)

The total number of protons in the nucleus of an atom, which identifies the element.

Mass number ($A$)

The whole-number sum of protons and neutrons in the nucleus of a specific isotope.

Alpha particle

A emitted helium nucleus represented as $^{4}_{2}\text{He}$ or $\alpha$, which decreases parent mass number $A$ by 4 and atomic number $Z$ by 2.

Beta minus particle

An emitted high-energy electron represented as $^{0}_{-1}e$ or $\beta^-$, created when a neutron converts into a proton and increasing atomic number $Z$ by 1.

Positron

An emitted particle represented as $^{0}_{+1}e$ or $\beta^+$, created when a proton converts into a neutron and decreasing atomic number $Z$ by 1.

Gamma radiation

High-energy electromagnetic radiation represented as $^{0}_{0}\gamma$ emitted during nuclear decay without changing mass number $A$ or atomic number $Z$.

Curie ($Ci$)

A unit measuring radioactive activity as the rate or number of nuclear decays per unit time.

Rem

A unit measuring the biological damage or effect of radiation exposure on living tissue.

Half-life

The time required for one-half of the radioactive nuclei or activity in a sample to decay.

Valence shell

The highest occupied principal energy level of an atom containing the electrons involved in chemical bonding.

Octet rule

The principle that main-group atoms tend to gain, lose, or share electrons to attain a noble-gas valence electron configuration of 8 electrons (or 2 for hydrogen).

Mole

The SI base unit for amount of substance, containing Avogadro's number ($6.02 \times 10^{23}$) of chemical entities.

Molar mass

The mass in grams of one mole of a chemical element or compound, expressed in $g/mol$.

Electron domain

A region of high electron density around a central atom in VSEPR theory, consisting of a single bond, multiple bond, or nonbonding lone pair.

Electronegativity

The relative measure of an atom's ability to attract shared electrons within a chemical bond.

Mixture

Physical blend'; variable composition; can be physically separated

kilo (k)

10³. If you’re at the base of king and want to go back to, grams, for example, you would divide by 1000.

centi - c

10⁻². Means one hundredth of a dollar. “chocolate” 100 of it = 1 meter

mili (m)

10⁻³. Means one thousandth of a unit, such as a meter or a gram. (x1000)

length

For unit, meter (m) is used to measure…?

volume

For unit, liter (L) is used to measure…?

mass

For unit, gram (g) is used to measure…?

1 meter

100 centimeters = how many meters

1000 micrograms

1 milligram = how many micrograms (μg)

1000mg

1g = how many miligrams

100 ng

1 microgram (μg) = how many nanograms (ng)

micro

10⁻⁶. (x10⁻⁶) 3 spaces to the left of milli. It is a metric prefix used to denote one millionth of a unit (μ)

nano

10⁻⁹ (x10⁻⁹). 3 spaces to the left of micro. It is a unit prefix in the metric system representing one billionth of a unit (n).

2.2 lbs

1 kg is equal to how many pounds

1000 g

1 kilogram equals how many grams (mass)

1000 miligrams

1 gram equals how many miligrams (mass)

1000 mL

1 Liter equals how many mL (volume)

1 mL = 1 cubic centimeter = 1 cc

1 mL equals how many cubic centimeters (cm³) / how many cc (cubic centimeters). Include 1 mL = in your answer.

4.184 J

1 cal = how many joules (J). Approximately the energy needed to raise 1 gram of water by 1 °C (energy).

1 Cal = 1 kcal = 1000 cal

1 Cal = how many kilocalories (kcal) = how many calories (cal). Cal is nutrition (food calorie) (energy). Include 1 Cal = in your answer.

Avogadro’s number

6.02 × 10²³ particles/mol

6.02 × 10²³ particles/mol

What is avogadro’s number and over what?

Percent

Part / whole x 100%

Part / whole x 100%

Percent; how to calculate. Percent is “per 100”

decimal part x whole

Find part formula (25% of 80 = 0.25 × 80 = 20)

Finding part

decimal part x whole (25% of 80 = 0.25 × 80 = 20)

Density

d = m/v (mass per unit volume, commonly g/mL). What is d?

mass

m = dV What is m?

Volume

V = m/d - What is V?

m / d x V

how is the helpful triangle arranged for density

Specific gravity (SG)

= density of substance / density of water (how dense is this substance compared to water). Usaully g/mL.

1.0g/mL

Waters approximate density is…

Water density

1.0g/mL represent…?

density of substance over density of water (1.0g/mL)

SG formula =

SG formula

density of substance over density of water (1.0g/mL)

°F → °C

°C = (°F − 32) × 5/9

°C = (°F − 32) × 5/9

°F → °C FORMULA

°C → °F

°F = (°C × 9/5) + 32

°F = (°C × 9/5) + 32

°C → °F

°C → K

K = °C + 273 (should be provided)

K→ °C

°C = K − 273 (Should be provided)

4.184 J

1 cal = ? J

1000 cal

1 Calorie (food Cal) = ? cal

Heat

Energy transferred because of temperature difference.

Solid

Fixed shape and volume; particles vibrate in place

Liquid

Fixed volume, variable shape; particles flow past each other

Gas

Variable shape and volume; highly compressible; particles far apart

Proton

p⁺. In the nucelus of an atom. (1 amu - atomic mass unit): +1 charge

P+

Proton charge. In the nucleus of an atom. (1 amu - atomic mass unit): +1 charge

n0

neutron charge. In the nucleus of an atom (1 amu - atomic mass unit): 0 charge

neutron

n⁰. In the nucleus of an atom. (1 amu - atomic mass unit): 0 charge

Mass number

Protons plus neutrons

Protons plus neutrons

mass number / atomic number

Nucleus

protons and neutrons are found in the

Electron cloud

Electrons are found in the

electron

e⁻ is…? (0 amu - atomic mass unit): -1 charge

e-

Electron charge (0 amu - atomic mass unit. In an electron cloud: -1 charge

+1

Charge of proton

0

Charge of neutron

-1

Charge of electron

number of protons and identifies the element

Atomic number equals number of blank and identifies what

Atomic number

Number of protons and identifies the element

Neutrons

Mass number minus atomic number

mass number - atomic number

Neutrons formula - how to find

Atomic number

Number of protons, identifies the element

Number of protons and identifies the element

What does the atomic number do?

Isotope

Version of the same element with a different number of neutrons

Whole number

When looking at the mass number for an isotope, it must be a BLANK number

fewer e- than p+

Ion electrons: cation means