Chemistry Chapter 3 Review Flashcards

Questions and Answers

What does the Law of Conservation state?

Only certain elements can form compounds

Matter and mass cannot be created or destroyed in chemical reactions (correct)

Atoms can be created or destroyed in chemical reactions

Mass ratios of the elements in compounds can change

What is the Law of Definite Proportions?

Mass ratios of the elements that make up a given compound are always the same.

What does the Law of Multiple Proportions state?

Only whole numbers can be used to combine elements to form compounds.

What is an atom?

The smallest particle of an element that retains the chemical properties of that element. Signup and view all the answers

What are the two regions that make up all atoms?

Nucleus and Electrons. Signup and view all the answers

The properties of electrons made by Thomson & Millikan are: 1. Present in all atoms and elements, 2. Mass and charge never change, 3. Electrons have a large _____ to mass ratio, 4. Electrons have a mass of 9.109 x 10 -31 kg.

charge Signup and view all the answers

How can Rutherford's model of the atom be summarized?

Electrons bounced back on the gold foil indicating a positive charge in the center. Signup and view all the answers

What number uniquely identifies an element?

Atomic number. Signup and view all the answers

What are isotopes?

Atoms of the same element that have different masses. Signup and view all the answers

How are isotopes alike?

They have the same atomic number. Signup and view all the answers

How are isotopes different?

Different number of neutrons. Signup and view all the answers

What is the atomic number of an element?

Number of protons. Signup and view all the answers

What is the mass number of an isotope?

Total number of protons and neutrons that make up the nucleus. Signup and view all the answers

What is a mole?

Amount of substance that contains as many particles as there are atoms in exactly 12g of carbon-12. Signup and view all the answers

What is the abbreviation for mole?

mol. Signup and view all the answers

How many particles are in one mole?

6.022 x 10^23. Signup and view all the answers

What is the name given to the number of particles in a mole?

Avogadro's number. Signup and view all the answers

What is the molar mass of an element?

Numerically equal to the atomic mass of the element in atomic mass units (g/mol). Signup and view all the answers

How is the mass in grams of the element converted to the amount in moles?

Multiply grams by moles then divide by atomic mass. Signup and view all the answers

How is the mass in grams of the element converted to the number of atoms?

Divide by molar mass and multiply by Avogadro's number. Signup and view all the answers

What is the nucleus of an atom?

Very small region in the center of an atom that contains protons and neutrons. Signup and view all the answers

Who discovered the atomic nucleus?

Rutherford. Signup and view all the answers

What are the two kinds of particles that make up the nucleus?

Protons and neutrons. Signup and view all the answers

What are two compounds that demonstrate the Law of Multiple Proportions?

Carbon dioxide and Carbon monoxide. Signup and view all the answers

How do you convert moles to grams?

Multiply mol by grams then divide by mol (usually 1). Signup and view all the answers

How do you convert grams to moles?

Multiply grams given by mol (usually 1) then divide by atomic number. Signup and view all the answers

How do you convert moles to atoms?

Multiply moles given by Avogadro's number. Signup and view all the answers

How do you convert grams to atoms?

Multiply grams by Avogadro's number then divide by molar mass. Signup and view all the answers

Study Notes

Key Laws in Chemistry

Law of Conservation: Matter and mass cannot be created or destroyed in chemical reactions.
Law of Definite Proportions: Elements in a compound exist in fixed mass ratios regardless of the amount or method of formation.
Law of Multiple Proportions: Compounds are formed from elements in whole number ratios.

Atomic Structure

Atom: The smallest particle of an element retaining its chemical properties.
Regions of Atoms: Comprised of a nucleus (center with protons and neutrons) and electrons (surrounding the nucleus).

Electron Properties

Present in all atoms and elements.
Have consistent mass and charge.
Possess a high charge-to-mass ratio.
Mass of an electron is approximately 9.109 x 10^-31 kg.

Rutherford's Atomic Model

Discovered positive charge in the center due to electrons bouncing back during gold foil experiment.

Atomic Identity

Atomic Number: Unique number identifying an element, equal to the number of protons.
Isotopes: Variants of the same element with different masses due to differing neutron numbers.
Isotopes share the same atomic number but differ in neutron count.

Mass and Moles

Mass Number: Total of protons and neutrons in an isotope's nucleus.
Mole: Quantity containing the same number of particles as atoms in 12g of carbon-12, defined as 'mol'.
Avogadro's Number: The number of particles in one mole, approximately 6.022 x 10^23.

Molar Mass

Equal numerically to the atomic mass and expressed in g/mol.
Conversion between grams and moles and vice versa requires formulas based on molar mass.

Conversion Formulas

Moles to grams: Multiply moles by molar mass.
Grams to moles: Divide grams by molar mass.
Moles to atoms: Multiply moles by Avogadro's number.
Grams to atoms: Convert grams to moles and then to atoms using Avogadro's number.

Structure of the Nucleus

Comprised of protons and neutrons, discovered by Rutherford.

Examples of Chemical Compounds

Demonstrating Law of Multiple Proportions: Carbon dioxide (CO2) and carbon monoxide (CO).

Additional Notes

Maintain clarity in unit conversion steps to avoid mistakes in calculations.

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Revise key concepts from Chemistry Chapter 3 with these flashcards. Each card presents essential laws that govern chemical reactions, including the conservation of mass and the proportions of compounds. Perfect for quick review and reinforcement of foundational chemistry principles.