Laws of Chemical Combination & Dalton's Theory

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Questions and Answers

Which of the following statements is NOT part of Dalton's Atomic Theory?

Compounds are composed of atoms in definite ratios.

Atoms can be created and destroyed during chemical reactions. (correct)

Elements are made up of very small particles called atoms.

All atoms of an element are identical in mass and size.

The Law of Conservation of Mass states that the total mass of reactants will always equal the total mass of products in a chemical reaction.

True

Who formulated the Law of Conservation of Mass?

Antoine Lavoisier

In the Law of Definite Proportion, a specific chemical compound always contains its elements in a fixed ratio by _____.

weight Signup and view all the answers

Match each law of chemical combination to its definition:

Law of Conservation of Mass = Mass remains constant during a chemical reaction. Law of Definite Proportion = A given compound contains its elements in a fixed ratio. Law of Multiple Proportions = Elements can combine in various ratios to form different compounds. Signup and view all the answers

Which of the following examples illustrates the Law of Conservation of Mass?

5.19 g of CaCO3 produces 1.99 g of CO2 and 3.2 g of CaO. Signup and view all the answers

Compounds can contain their constituent elements in varying ratios depending on their preparation method.

False Signup and view all the answers

What will happen to the mass of reactants when they undergo a chemical reaction according to the Law of Conservation of Mass?

The mass will remain the same. Signup and view all the answers

What is the mass of hydrogen that will react with 10.00 g of oxygen?

1.25 g Signup and view all the answers

The Law of Multiple Proportions states that elements can combine in various ratios, including whole numbers like 2:1.

True Signup and view all the answers

What suffix is used for cations with a higher charge when naming?

–ic Signup and view all the answers

In carbon monoxide, 1.00 g of carbon combines with ___ g of oxygen.

1.33 Signup and view all the answers

Match the polyatomic ions with their corresponding formulas:

Hydroxide = OH- Sulfate = SO42- Nitrate = NO3- Phosphate = PO43- Signup and view all the answers

Which one of the following is a correct naming for a monoatomic anion?

Bromide ion Signup and view all the answers

The suffix –ite is used for polyatomic ions that have more oxygen atoms than their –ate counterparts.

False Signup and view all the answers

Name the ion represented by SO32-.

sulfite Signup and view all the answers

Study Notes

Laws of Chemical Combination

Elements are made up of tiny particles called atoms.
All atoms of an element are identical in mass and size, differing from atoms of other elements.
Atoms of different elements have different shapes/figures that represent them.
Compounds are formed from atoms of different elements in definite proportions with whole-number ratios.
During a chemical reaction, atoms are rearranged, combining or separating but never created or destroyed.

Dalton's Atomic Theory

Elements are composed of atoms.
All atoms of a given element are identical in mass and size, differentiating them from atoms of another element.
Compounds are formed by atoms of different elements combining in definite whole number ratios.
During a chemical reaction atoms combine, separate, or rearrange. No atoms are created or destroyed.

Introduction

In studying matter, we observe phenomena that can be reproduced at will.
Scientific facts are observed phenomena that can be reproduced.
Scientific laws are summaries of numerous scientific facts that are expressed as broad statements.

Laws of Chemical Combination

Law of Conservation of Mass: In an ordinary chemical reaction, there is no noticeable change in the total mass of substances involved before and after the reaction. Mass of reactants equals mass of products.
- Lavoisier's experiment with mercuric oxide illustrates this law.
- A sample problem demonstrating this law is provided.
Law of Definite Proportions: A given chemical compound always contains its constituent elements in a fixed ratio (by mass). The ratio doesn't depend on the source or preparation method.
- A sample problem illustrating the law is given.
Law of Multiple Proportions: When two elements form more than one compound the ratio of the masses of one element that combine with a fixed mass of the other element is a ratio of small whole numbers.
- A sample problem about carbon and oxygen illustrates this law.

Atoms, Molecules, and Ions

Atoms combine to form molecules.
Atoms lose or gain electrons to form ions.
Positive ions are called cations.
Negative ions are called anions.
Ions can be formed by a single atom (monoatomic) or multiple atoms (polyatomic) .

Naming Monoatomic Ions

Cations: The name of the element remains unchanged. If multiple ions are possible, a suffix -ic (higher charge) or -ous (lower charge) is added.
Anions: The name of the element is modified with the suffix -ide.

Naming Cations

Examples of cations include zinc ion, magnesium ion, potassium ion, ferrous ion (or iron(II)) ion and ferric ion (or iron(III)) ion.

Naming Anions

Examples of anions include bromide ion, sulfide ion, oxide ion, and iodide ion.

Polyatomic Ions

Several anions are polyatomic (composed of more than one atom).
Polyatomic anions are named using the root word of the central atom and using suffixes -ate (higher oxygen content) or -ite (lower oxygen content).
Examples include hydroxide ion, cyanide ion, nitrate ion, nitrite ion, sulfite ion, sulfate ion, phosphate ion.
Some anions have common names ending with the suffix -ate. Examples include acetate ion, oxalate ion.

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Description

Explore the fundamental principles of chemical combinations and Dalton's Atomic Theory. This quiz covers the composition of elements, atom properties, and the formation of compounds through atomic interactions. Test your understanding of these essential concepts in chemistry.