Chemistry C2

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The percentage of an element in a compound can be calculated from the relative mass of the element in the formula and the relative formula mass of the compound.
The empirical formula of a compound can be calculated from the masses or percentages of the elements in a compound.
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Even though no atoms are gained or lost in a chemical reaction, it is not always possible to obtain the calculated amount of a product.
Because: it is reversible, some of the product may be lost when it is separated from the reaction mixture, some of the reactants may react in ways different from the expected reaction.
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The amount of a product obtained is known as the yield. When compared with the maximum theoretical amount as a percentage, it is called the percentage yield.
In some chemical reactions, the products of the reaction can react to produce the original reactants, called reversible reactions.
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Reversible reactions example: ammonium chloride -------> ammonia + hydrogen chloride
Chemical reactions can only occur when reacting particles collide with each other and with sufficient energy. The minimum amount of energy particles must have to react is called the activation energy.
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Rate of reaction = amount of product formed divided by time
Rate of reaction = amount of reactant used divided by time
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Increasing the temperature increases the speed of the reacting particles so that they collide more frequently and more energetically. This increases the rate of reaction.
Increasing the pressure of reacting gases increases the frequency of collisions and so increases the rate of reaction.
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Increasing the concentration of reactants in solutions increases the frequency of collisions and so increases the rate of reaction
Increasing the surface area of solid reactants increases the frequency of collisions and so increases the rate of reaction.
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Other cards in this set

Card 2

Front

Because: it is reversible, some of the product may be lost when it is separated from the reaction mixture, some of the reactants may react in ways different from the expected reaction.

Back

Even though no atoms are gained or lost in a chemical reaction, it is not always possible to obtain the calculated amount of a product.

Card 3

Front

In some chemical reactions, the products of the reaction can react to produce the original reactants, called reversible reactions.

Card 4

Front

Chemical reactions can only occur when reacting particles collide with each other and with sufficient energy. The minimum amount of energy particles must have to react is called the activation energy.

Card 5

Front

Rate of reaction = amount of reactant used divided by time