Chemistry: Units, Matter, Atoms, and Isotopes

A set of Q&A flashcards covering unit conversions (liters, milliliters, meters, centimeters, and cubic meters) and fundamental chemistry concepts (matter, atoms, elements, isotopes, atomic number, and atomic mass) based on the lecture notes.

Why is tracking units important when converting to cubic meters in chemistry?

Because the numeric value without a unit is meaningless; you must cancel units one by one (e.g., L to mL, then to m^3) to reach the target unit, cubic meters.

What is the relationship between liters and milliliters?

1 liter equals 1000 milliliters; equivalently, 1 milliliter equals 10^-3 liters.

How can you cancel liters when converting to cubic meters?

Use a conversion factor so liters cancel; e.g., 1 L = 1000 mL, arranging factors so liters appear on both sides and cancel.

What does 10^3 signify in the liters-to-milliliters context?

10^3 equals 1000, reflecting that 1 L = 1000 mL.

How many centimeters are in a meter, and how does this affect cubic meter conversions?

1 meter = 100 centimeters; for cubic meters, 1 m^3 = (100 cm)^3 = 1,000,000 cm^3, so you must cancel cm^3 when converting to m^3.

What is matter?

Matter is anything that has mass and occupies space.

What is an atom, according to the notes?

The smallest particle of matter (as described in the notes) made up of protons, neutrons, and electrons; cannot be broken down further in that model.

What is an element?

A pure substance made of one type of atom; elements on the periodic table are defined by their atomic number (the number of protons).

What is the atomic number?

The number of protons in the nucleus; determines the element's identity.

What is an isotope?

Atoms of the same element with different numbers of neutrons; same element identity but different mass numbers.

What is atomic mass and where is it shown on the periodic table?

Atomic mass is the weighted average of all isotopes' masses; shown as the bottom number on the periodic table (the top number is the atomic number).

What are the masses and charges of protons and neutrons?

Protons have mass ≈1 amu and charge +1; neutrons have mass ≈1 amu and charge 0.

What is the charge of an electron and its role in neutral atoms?

Electrons have charge −1; in a neutral atom, the number of electrons equals the number of protons, balancing the charge.

What determines an element's reactivity and identity?

Identity is determined by the number of protons (atomic number); electrons determine how it reacts in chemical processes.