Chapter 3: Matter and Energy

Flashcards covering matter classification, phase changes, temperature conversions, physical vs. chemical changes, energy types, specific heat, and heating curves from Chapter 3 notes.

What are the two main categories that matter is classified into?

Matter is classified into pure substances and mixtures.

What is a pure compound?

A substance consisting of two or more elements chemically combined that cannot be easily physically separated (e.g., $H_2O$ or $CO_2$).

What is the difference between a homogeneous mixture and a heterogeneous mixture?

A homogeneous mixture is completely mixed so that every sample is the same (e.g., milk), whereas a heterogeneous mixture is not completely mixed so every sample has differences (e.g., chocolate chip cookie or muddy water that has sat).

What are sublimation and deposition?

Sublimation is the direct phase transition from solid to gas (e.g., dry ice / solid $CO_2$), while deposition is the direct phase transition from gas to solid (e.g., dew turning to frost in winter).

What are the main differences between solids, liquids, and gases regarding shape and volume?

Solids are very compacted with a fixed shape; liquids move, take the shape of their container, and have no fixed shape; gases do not have a fixed size or shape.

What are the temperature conversion formulas for Celsius ($T_C$) to Fahrenheit ($T_F$) and Kelvin ($T_K$)?

Fahrenheit conversion: $T_F = 1.8 T_C + 32$; Kelvin conversion: $T_K = T_C + 273$.

What temperature represents absolute zero on the Kelvin scale?

$0\,\text{K}$ is absolute zero.

How do physical changes differ from chemical changes?

Physical changes are reversible and do not change chemical structure, whereas chemical changes produce something new and are not reversible.

What is the difference between potential energy and kinetic energy?

Potential energy is stored energy from holding position, while kinetic energy is energy of movement (e.g., an earthquake or a speeding car).

What are the conversion factors between Joules, calories, and kilocalories?

$1\,\text{cal} = 4.184\,\text{J}$ and $1\,\text{kcal} = 1\,\text{Cal} = 1000\,\text{calories}$.

How much energy in \text{kcal/g} and \text{kJ/g} do carbohydrates, fats, and proteins provide?

Carbohydrates provide $4\,\text{kcal/g}$ ($17\,\text{kJ/g}$); Fats provide $9\,\text{kcal/g}$ ($38\,\text{kJ/g}$); Proteins provide $4\,\text{kcal/g}$ ($17\,\text{kJ/g}$).

What is specific heat?

The amount of heat (energy) needed to raise the temperature of exactly one gram of a substance by exactly one degree Celsius ($^\circ\text{C}$).

Why is water's high specific heat important for Earth and living organisms?

Because water has a high specific heat ($1.00\,\text{Cal}/g^\circ\text{C}$), it resists temperature changes, preventing dramatic temperature shifts on Earth and helping regulate temperature in living bodies.

In this heating curve diagram, what physical transitions happen at $0^\circ\text{C}$ and $100^\circ\text{C}$ for water?

At $0^\circ\text{C}$, solid ice melts into liquid water (using heat of fusion, $80\,\text{Cal/g}$). At $100^\circ\text{C}$, liquid water boils/evaporates into gas (using heat of vaporization, $540\,\text{Cal/g}$).