G10 Unit 28 Applications of Controlled Reaction Rates

Question 1

Reaction rates can be controlled.

For instance, the reaction rates of food spoilage, corrosion, and burning of fuel can be retarded.

There are many applications that benefit us by controlling chemical reactions.

These may be found in the fields of medicine, in industrial settings, or in other fields.

Question 2

Food spoilage is a naturally occurring chemical process.

Food spoilage is caused multiple factors, the most common being either by chemical or microbial agents.

Question 3

are usually in the form of fungi or bacteria that produce substances like enzymes and other toxic chemicals that render the food inedible.

Answer 3

Microbial agents

Question 4

on the other hand, involve the chemical reactions that cause food to become inedible.

Answer 4

Chemical agents

Question 5

The type of food may be susceptible to certain factors that can cause the spoilage.

Question 6

works in the same manner as catalysts but has an opposite effect; it slows down chemical reactions.

Answer 6

inhibitor

Question 7

are inhibitors added to food products to slow down the chemical reactions involved with food spoilage and extend the period in which the food remains edible

Answer 7

Preservatives

Question 8

Some preservatives are benzoic acid (C7H6O2C7H6O2) and butylhydroxytoluene (C15H24OC15H24O).

Question 9

Freezing the food also slows down the chemical reactions that lead to spoilage by causing the molecules of the food to move slower.

Question 10

reaction of metals with oxygen forming metal oxides

Answer 10

Corrosion

Question 11

a synthesis reaction that usually happens if a metal is excessively exposed to oxygen or water

Answer 11

Corrosion

Question 12

An example of corrosion commonly seen is rust on iron.

Question 13

Surface area has a direct effect on metal corrosion. When the exposed area of the metal is larger, the rate of corrosion of the metal is faster.

Question 14

Corrosion weakens iron and damages iron-made structures, such as footbridges and communication towers.

Question 15

used to shield iron from the oxygen molecules of the atmosphere and prevent the formation of rust.

Answer 15

Paint

Question 16

effectively coats the corrodible metal against oxygen in the atmosphere.

Answer 16

Paint

Question 17

Another method is dipping the iron in molten zinc, and results in zinc externally coating the iron.

Question 18

Zinc can react with oxygen molecules in the atmosphere to form zinc oxides, which are impermeable, so no oxygen molecule can reach the iron inside.

Question 19

In case of a fire, the burning of fuel must be retarded or decreased in rate to effectively stop the flame.

Question 20

chemical reaction that causes fires to start and continue burning

Answer 20

combustion

Question 21

fire triangle

Answer 21

fuel
oxygen
heat

Question 22

The components of the fire triangle need to be disrupted in order to effectively put out a fire that is already burning.

There are many ways of stopping fires, and most of these directly involve stopping the chemical reactions that cause fires.

One of the simplest methods involves using sand or water for retarding flames.

Question 23

_ of the contents of a fire extinguisher allow the flame retardant to exit the tank forcefully

Answer 23

Pressurization

Question 24

Some fire extinguishers use pressurized water as the retardant.

CO2CO2extinguishers use carbon dioxide for extinguishing the fire.

LiquidCO2CO2is stored inside the tank, and it remains a liquid as long as it is pressurized.

Question 25

Another way of retarding flames usingCO2CO2is by relying on the physical property of substances known as the _ _ _ _.

Answer 25

latent heat of vaporization

Question 26

amount of heat absorbed by a substance when it changes phases from liquid to gas

Answer 26

latent heat of vaporization

Question 27

An example of a chemical used in fire extinguishers ismonoammonium phosphate(also known as MAP), with the formulaH6NO4PH6NO4P.

Fire extinguishers containing this substance are sometimes known asABC extinguishers.

MAP extinguishers work by lowering the surface area of the substances that can burn, and also lowers the oxygen supply of the fire since it makes a barrier between the fire and air.