Dalton's atomic theory developed
in the early 1800s became the basic of chemistry development, especially in explaining
chemical reactions. The development of Dalton atomic theory strongly related with the observation of 17th century chemists. They observed the relation between the number of product and its reactants. Their observation resulted the basic chemical laws. What are the contents and uses of the basic chemical laws?
Priestley called that colorless gas as phlogiston. However, Lavoisiser doubted the existence of phlogiston gas. He proposed that pglogiston was actually oxygen gas. Then, Lavoisier repeated Priestley's experiment to approve his opinion. he measured the mass mercury oxide before and after the combustion using a very sensitive measure. He found that there was a decrease in mercury oxide mass.
Lavoisier explained the reason why mercury oxide mass decreased. When it was heated, mercury oxide produced oxygen gas, so its mass was in decreased. Lavoisier also proved the opposite reaction. If a metal was heated in air, its mass increased along with the number of oxigen taken from the air. Lavoisier's conclusion is called the law of conservation of mass.
With Lavoisier's discovering, the phlogiston theory that was believed by chemists for 100 years finally fell. Lavoisier also declared that the process of sweating is the product of slow combustion in our body. When we do activities, food in our body will burn and react to produce water as sweat and CO2.
The law of mass conservation also inspired Dalton when he declared his atomic theory. Dalton declared that atom is the tiny smallest ball, cannot crack, created, or disappeared. Not only that, the law of conservation of mass can also answer the question of. "Why equation of reaction has to be balanced?". Look at this equation.
Example 4.1
3,2 gram of sugar pwoder is reacted with oxygen gas to produce sulfur dioxides gas of 64 gram. How many gram of oxygen have been reacted?
Solution
Lavoisier explained the reason why mercury oxide mass decreased. When it was heated, mercury oxide produced oxygen gas, so its mass was in decreased. Lavoisier also proved the opposite reaction. If a metal was heated in air, its mass increased along with the number of oxigen taken from the air. Lavoisier's conclusion is called the law of conservation of mass.
With Lavoisier's discovering, the phlogiston theory that was believed by chemists for 100 years finally fell. Lavoisier also declared that the process of sweating is the product of slow combustion in our body. When we do activities, food in our body will burn and react to produce water as sweat and CO2.
The law of mass conservation also inspired Dalton when he declared his atomic theory. Dalton declared that atom is the tiny smallest ball, cannot crack, created, or disappeared. Not only that, the law of conservation of mass can also answer the question of. "Why equation of reaction has to be balanced?". Look at this equation.
3,2 gram of sugar pwoder is reacted with oxygen gas to produce sulfur dioxides gas of 64 gram. How many gram of oxygen have been reacted?
Solution
Sulfur powder + Oxygen gas ----> sulfur dioxides gas
32 g ? 64 g
Mass of substances before reaction equals with mass of substances after reaction.
sulfur mass + oxygen mass = mas of sulfur dioxydes gas
32 g + mass of oxygen gas = 64 g
Mass of oxygen gas = 64 g - 32 g = 32 g
Exercise
One gram of magnesium metal is reacted with chlorine gas to produce magnesium chloride of 4 gram. How many gram of chlorine gas have been reacted?
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