Quiz Dalton's Atomic Theory and Supporting Laws

What is one of the main postulates of Dalton’s atomic theory?

• Atoms are destroyed during chemical reactions.

• Atoms combine in fixed, whole-number ratios to form compounds.

• Atoms are always visible under a microscope.

• Atoms are created during chemical reactions.

What does the Law of Conservation of Mass state?

• Mass is destroyed in a chemical reaction.

• Mass can only increase during chemical reactions.

• Mass is neither created nor destroyed during chemical reactions.

• Mass depends on the volume of the reactants.

What is the Law of Definite Proportions?

• Compounds are made of elements in random proportions.

• Compounds always contain the same elements in the same mass ratio.

• Elements combine in any ratio to form compounds.

• Elements always react to form identical masses.

Which statement best describes the Law of Multiple Proportions?

• Elements combine in any ratio to form compounds.

• When elements form more than one compound, the masses of one element combine with a fixed mass of the other in whole-number ratios.

• Atoms in compounds are always identical.

• Compounds always have the same number of atoms of each element.

Sample Problem: Law of Conservation of Mass In a reaction, 12.5 grams of calcium reacts with 19.8 grams of chlorine to form calcium chloride. What is the total mass of calcium chloride produced?

• 32.3 grams

• 30.0 grams

• 20.0 grams

• 34.5 grams

Sample Problem: Law of Definite Proportions Two samples of water are analyzed. Sample 1: 2.00 grams of hydrogen combine with 16.00 grams of oxygen. Sample 2: 4.00 grams of hydrogen combine with 32.00 grams of oxygen. What do these results show?

• Water always contains hydrogen and oxygen in a fixed ratio by mass.

• Water contains hydrogen and oxygen in random proportions.

• Water’s composition changes depending on the source.

• Water’s mass ratio depends on the temperature.

Sample Problem: Law of Multiple Proportions Two compounds made of nitrogen and oxygen are analyzed. Compound A: 2.80 grams of nitrogen combine with 1.60 grams of oxygen. Compound B: 2.80 grams of nitrogen combine with 3.20 grams of oxygen. What is the ratio of oxygen in Compound A to Compound B?

• 1:1

• 1:2

• 2:1

• 3:2

Why does Dalton’s atomic theory explain the Law of Conservation of Mass?

• Atoms are created and destroyed in chemical reactions.

• Atoms cannot be created or destroyed, only rearranged.

• Atoms lose mass during chemical reactions.

• Atoms disappear after forming compounds.

How does Dalton’s atomic theory explain the Law of Definite Proportions?

• Atoms combine in specific, whole-number ratios to form compounds.

• Atoms form compounds in infinite proportions.

• Atoms of different elements are always identical.

• Atoms combine randomly to form compounds.

Which of the following is an example of the Law of Multiple Proportions?

• Water is always made of two hydrogen atoms and one oxygen atom.

• Carbon monoxide (CO) and carbon dioxide (CO₂) show oxygen masses in a 1:2 ratio.

• The total mass of a compound is always conserved.

• Elements combine in random ratios to form compounds.