CHM 50 Preparatory Chemistry I Health Science - Matter, Atoms, Elements, Compounds, and Mixtures Flashcards

Flashcards covering core concepts from CHM 50 lecture notes: matter, states, atoms, elements, compounds, mixtures, and fundamental properties and changes.

What is the balanced equation for the reaction of nitrogen monoxide with oxygen to form nitrogen dioxide?

2 NO(g) + O2(g) → 2 NO2(g)

How is matter defined?

Anything that has mass and occupies space.

Name the three fundamental states of matter.

Solid, liquid, and gas.

What is a pure substance?

A substance composed of only one kind of atom or only one kind of compound.

What is an element?

A pure substance made of only one kind of atom; elements can be monatomic or diatomic (e.g., He, O2).

What is a compound?

A chemical combination of two or more elements.

What is a molecule?

Two or more atoms bonded together.

What is a monatomic element?

Elements that exist as single, unconnected atoms (e.g., He, Ne).

What is a polyatomic molecule?

A molecule containing two or more atoms (e.g., H2O, CO2).

Why is the number 1 not written as a subscript in chemical formulas?

Because the formula implies one atom of that element.

What is the chemical formula for water and how many atoms are in each molecule?

H2O; 3 atoms per molecule.

What distinguishes pure substances from mixtures?

Pure substances have fixed composition; mixtures contain two or more pure substances and can be separated by physical means.

What is a homogeneous mixture?

A mixture with uniform composition throughout (one visible phase).

What is a heterogeneous mixture?

A mixture with two or more visibly distinct phases.

Is seawater a homogeneous or a heterogeneous mixture?

Homogeneous mixture (a solution).

Is a slice of watermelon a homogeneous or a heterogeneous mixture?

Heterogeneous mixture.

What are physical properties?

Characteristics that can be observed without changing the substance's composition (e.g., color, odor, mp, bp, density).

What are chemical properties?

Characteristics observed when a substance changes its composition (e.g., combustibility, reactivity).

Give examples of physical properties of water.

Colorless, odorless, bp 100°C, mp 0°C, density 1 g/mL, non-flammable.

Give examples of chemical properties of water.

Can be decomposed by electrolysis to H2 and O2; reacts with chlorine to form HCl and HOCl.

What is electrolysis?

The decomposition of a compound by passing electricity (e.g., H2O → H2 + O2).

What is a physical change?

A change in which the substance's composition remains the same (e.g., melting, boiling).

What is a chemical change?

A change that produces at least one new substance with different properties (e.g., rusting).

Name four evidences of a chemical reaction.

Color change, gas production, formation of a precipitate, energy release or absorption.

What is sublimation?

Solid to gas without passing through the liquid phase.

What is deposition?

Gas to solid without passing through the liquid phase.

How do solids, liquids, and gases differ in terms of shape and volume?

Solids have definite shape and volume; liquids have definite volume but indefinite shape; gases have indefinite shape and volume.

What are the two types of pure substances?

Elements and compounds.

What is density of water at standard conditions?

1 g/mL (or 1 kg/L).

What are monatomic and diatomic elements?

Monatomic elements exist as single atoms; diatomic elements exist as two-atom molecules (e.g., O2, N2).

What is an example of a diatomic molecule?

O2 (or N2).

What is stoichiometry?

The calculation of reactant and product amounts in chemical reactions using balanced equations.