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Some calcium carbonate and hydrochloric acid start to react. Water is then added to the...

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besterlinks | Student, Undergraduate | eNoter

Posted June 10, 2012 at 9:05 AM via web

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Some calcium carbonate and hydrochloric acid start to react. Water is then added to the reaction mixture. What happens to the speed of the reaction?

A   It decreases.

B   It increases.

C   It stays the same.

D   It stops

2 Answers | Add Yours

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sanjeetmanna | College Teacher | (Level 3) Assistant Educator

Posted August 25, 2012 at 12:44 AM (Answer #1)

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The rate of reaction can be determined either by measuring the amount of loss of reactants or formation of products.

Rate of reaction = `((amount of reactant used)/(time))`

or

Rate of reaction = amount of product formed/time

The reaction between calcium carbonate and dilute hydrochloric acid.

`CaCO_3 + 2 HCl -> CaCl_2 + CO_2 + H_2O`

For this reaction the rate of reaction can be measured by measuring the rate of CO2 formed.

Rate of reaction depends upon factors like...

Concentration

pressure

order

Temperature

Activation energy

Catalyst

For this reaction when we add water it will not effect the rate of reaction since the rate of reaction is measured by measuring the rate of CO2 formed but not water.

Therefore adding water will not effect the rate of reaction it will remain same.

Answer is option (C)

Sources:

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chaobas | College Teacher | Valedictorian

Posted June 13, 2012 at 12:26 AM (Answer #3)

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Rate of the reaction depend on the concentration of the reactant that is calcium carbonate and hydrochloric acid. So when water is added to the reaction mixture, the concentration will decrease there by decreasing the rate of the reaction.


So the answer is 

A. It decreases

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