(Chapter 3.3) Chemical Reactions: Reactions in Life

Question 1

Uses of acids

Answer 1

Acids are used in industry, fertilisers, and foods

Question 2

Use of bases

Answer 2

Bases are used for cleaning – soaps and cleaning agents

Question 3

What is gastric reflux?

Answer 3

The failure of the sphincter, a ring of muscle, between the stomach and the esophagus to keep gastric acids in the stomach

Question 4

What is gastric acid?

Answer 4

A digestive fluid formed in the stomach. Also known as stomach acid

Question 5

Is the environment of the stomach acidic, basic, or neutral and why?

Answer 5

Acidic as the lining of the stomach secretes an acid

Question 6

Is the environment of the small intestine acidic, basic, or neutral and why?

Answer 6

Basic as the substances inside the small intestine work optimally in a basic environment and the lining of the small intestine gets damaged by acids

Question 7

What substance in the stomach helps the body in digestion and how?

Answer 7

Gastric acid reduces the number of bacteria and breaks down proteins

Question 8

What substance in the small intestine helps the body in digestion and how?

Answer 8

Enzymes break down fats

Question 9

State the word and chemical equations of respiration

Answer 9

Word: Glucose + Oxygen –> Carbon Dioxide + Water + ATP
Chemical: C6H12O6 + 6O2 –> 6CO2 + 6H2O + ATP

Question 10

Define an aerobic reaction

Answer 10

A reaction used by organisms to convert oxygen into energy

Question 11

State the word and chemical equations of lactic acid fermentation

Answer 11

Word: Glucose –> Lactic Acid + ATP
Chemical: C6H12O6 –> 2C3H6O3 + ATP

Question 12

Why is respiration the prefered reaction?

Answer 12

Respiration yields 32 molecules of ATP from a singular molecule of glucose. On the other hand, latic acid fermentation only yields 2 molecules of ATP

Question 13

State ethanol fermentation as a word and chemical equation

Answer 13

Word: Glucose –> Ethanol + Carbon Dioxide + ATP
Chemical: C6H12O6 –> 2C2H5OH + 2CO2 + ATP

Question 14

Why is ethanol written as C2H5OH not C2H6O

Answer 14

Ethanol is expressed as C2H5OH as a result of the way the atoms of the substance are bonded and it highlights the substance having a hydroxy group (OH)

Question 15

In which organelle does photosynthesis occur in?

Answer 15

Chloroplasts

Question 16

What is the difference between a chloroplast and chlorophyll

Answer 16

Chloroplast is an organelle in plants and certain algae which contains a green pigment – chlorophyll

Question 17

What is the role of chlorophyll?

Answer 17

Chlorophyll absorbs light to power photosynthesis

Question 18

State the written and chemical equations of photosynthesis

Answer 18

Written: Carbon Dioxide + Water –> Glucose + Oxygen
Chemical: 6CO2 + 6H2O –> C6H12O6 + 6O2
Note: below and above the arrow, chlorophyll and light are necessary

Question 19

Out of the 4 chemical reactions, we have learnt so far, which can humans perform?

Answer 19

Respiration and lactic acid fermentation

Question 20

Why is the ocean becoming more acidic?

Answer 20

Due to actions from humanity, the atmosphere has more carbon dioxide and more carbon dioxide is being dissolved in the water to form carbonic acid

Question 21

Identify the substance(s) in gastric acid

Answer 21

Hydrochloric acid (HCl), potassium chloride (KCl), sodium chloride (NaCl), pepsin, and mucus

Question 22

Identify the role of the various acids in gastric acid

Answer 22

The acids kills bacteria and provides a medium

Question 23

Define pepsin

Answer 23

An enzyme in gastric acids that digests enzymes

Question 24

Identify the role of mucus in gastric acid

Answer 24

Mucus protects the stomach lining from the acids it secretes