How did Democritus and Dalton's approach to the same conclusion differ?

Answer 1

Chapter 3 Review- Atoms: The Building Blocks of Matter

(all answers below)

Democritus's view of matter was not supported by experimental evidence, thus leaving his ideas in speculation for years. Dalton's view is considered a theory due to his explanation of the law of conservation of mass, the law of definite proportions and the law of multiple proportions.

Direct words from the Modern Chemistry textbook (2011)

"By relating atoms to the measurable property of mass, Dalton turned Democritus's idea into a scientific theorythat could be tested by experiment.

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Here are all the questions and their corresponding answers:

1. Why is Democritus's view of matter considered only an idea, while Dalton's view is considered a theory?
   • Democritus's idea of matter does not relate atoms to a measurable property, while Dalton's theory can be tested through quantitative experimentation.
2. Give an example of a chemical or physical process that illustrates the law of conservation of mass.
   • A glass of ice cubes will have the same mass when the ice has completely melted into liquid water, even though its volume will change. (Accept any reasonable process.)
3. State two principles from Dalton's atomic theory that have been revised as new information has become available.
   • Atoms are divisible into smaller particles called subatomic particles. A given element can have atoms with different masses, called isotopes.
4. The formation of water according to the equation...

   2H2 + O2 → 2H2O

   ...shows that 2 molecules (made of 4 atoms) of hydrogen and 1 molecule (made of 2 atoms) of oxygen produce 2 molecules of water. The total mass of the product, water, is equal to the sum of the masses of each of the reactants, hydrogen and oxygen. What parts of Dalton's atomic theory are illustrated by this reaction? What law does this reaction illustrate?

   • Atoms cannot be subdivided, created, or destroyed. Also, atoms of different elements combine in simple, whole-number ratios to form compounds. The reaction also illustrates the law of conservation of mass.
5. If 3 g of element C combine with 8 g of element D to form compound CD, how many grams of D are needed to form compound CD2?
   • 16g
6. A sample of baking soda, NaHCO3, always contains 27.37% by mass of sodium, 1.20% of hydrogen, 14.30% of carbon, and 57.14% of oxygen.

   a) Which law do these data illustrate?

   • the law of definite proportions
   b) State the law.
   • A chemical compound contains the same elements in exactly the same proportions by mass regardless of the sample or the source of the compound.
7. Nitrogen and oxygen combine to form several compounds, as shown by the following table.

   a) 2.0

   b) 2.0 (really 1.9) (based on my calculations)

   c) 4.0 (really 4.9) (based on my calculations)

   d) law of multiple proportions

For the last ones, (#7) replace the "NO#" etc letters with the numbers in the chart and divide.

All of these answers come right from the answer book.

rec-co-m end me! (below)

Answer 2

Because Dalton actually had a theory. Democritus had an idea (not really based on anything in particular, and not falsifiable); other than that, he was basically talking out of the bottom end of his toga.

Answer 3

They both said the atom was the size of a Baseball and were correct.

Answer 4

Democritus had no experimental evidence to support his idea. John Dalton did have experimental evidence to support his theory.

Answer 5

The Democritus idea was not based on experimental data.

Answer 6

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