Chapter 3.1 Flashcards
(11 cards)
John Dalton thought that atoms
cannot be broken down further
Using improved chemistry equipment in the late 1700s, chemists observed that mass is neither created nor destroyed in a chemical reaction. This scientific law is called the law of
conservation of mass
In an experiment, Alex and Rachel discover that their sample of table salt, also known as sodium chloride, NaCl, consists of 39.34% by mass sodium, Na, and 60.66% by mass chlorine, Cl. Later, Alex wonders what the percentage of Na might be in the table salt in his saltshaker at home. Rachel tells him, correctly, that it is
39.34%
The fact that every sample of a particular chemical compound contains the same elements in exactly the same proportions by mass is known as the law of
definite proportions
A molecule of carbon monoxide, CO, has one atom of oxygen while a molecule of carbon dioxide, CO2, has two. In a sample of CO containing 1 g of carbon, 1.33 g of oxygen will combine with the carbon to form the molecule. What is the mass of oxygen in a sample of CO2 containing 1 g of carbon?
2.66g of oxygen
If two or more compounds are composed of the same two elements, then the ratio of the masses of the second element that is combined with a certain mass of the first element is always a ratio of small whole numbers. This statement is called the law of
multiple proportions
This part of Dalton’s atomic theory describes conservation of mass
Atoms cannot be subdivided, created, or destroyed
What is one way that Dalton’s atomic theory has been shown to be incorrect?
Atoms can be split into subatomic particles
Neutrons, protons, electrons
Law of conservation of mass
Matter cannot be created or destroyed during a reaction
Law of definite proportions
All compounds have a fixed composition that does not vary from sample to sample
Law of multiple proportions
For any two such compounds made of the sam stow elements, chemists found a simple ratio relating the masses of the variable element
