Chap 2: Atoms And Molecules

Question 1

Like other animals ….. have

Structures & mechanisms that defend them from …..

Answer 1

1. Ants

2. attack

Question 2

When threatened from above the ants shoot …. Into the air from their …..

Answer 2

1. Volleys of formic acid

2. Abdomens

Question 3

The acid that ants shoot bombards ….

Answer 3

The potential predator such as a hungry bird

Question 4

Formic acid got its name ….

Answer 4

From the Latin Word ant “formica”

Question 5

For a few ant species the formic acid isn’t shot out but….

Answer 5

Serves as a disinfectant that protects against microbial parasites

Question 6

Scientists have long known that chemicals play a major role in :

Answer 6

1. Insect Communication
2. Attraction of mates
3. Defence against predators

Question 7

Concept 2.1

…. Is a substance that cannot be broken down to other substances by ….

Answer 7

1. An element

2. Chemical reactions

Question 8

The number of elements occurring in nature, chemists recognize are?

Answer 8

92

Question 9

Symbol for sodium is … from the Latin word ….

Answer 9

1. Na

2. Natrium

Question 10

A …. Is a substance consisting of two or more different elements combined in a … ratio

Answer 10

1. Compound

2. fixed

Question 11

Pure sodium is a …
A) metal
B) non metal

Answer 11

Metal

Question 12

Pure chlorine is a …
A) poisonous liquid
B) poisonous gas

Answer 12

Poisonous gas

Question 13

After chemical combining sodium and chlorine form a …
A) gas
B) edible compound

Answer 13

Edible compound

Question 14

A … has different characteristics than its elements.
A) metal
B) matter
C) compound

Answer 14

Compound

Question 15

How many natural elements are there?
A) 90
B) 91
C) 92

Answer 15

92

Question 16

Out of … natural elements about … are essential elements.
A) 20 to 25%
B) 30 to 35%
C) 40 to 45%

Answer 16

20 to 25%

Question 17

An organism needs … to live a healthy life and reproduce
A) mandatory elements
B) essential elements

Answer 17

Essential elements

Question 18

Humans need … essential elements while plants need … essential elements
A) 20 and 17
B) 20 and 18
C) 25 and 17

Answer 18

25 and 17

Question 19

Four elements… make up approximately 96% of living matter.
A) oxygen, carbon, hydrogen and nitrogen
B) oxygen, nitrogen, sulphur and hydrogen

Answer 19

A

Question 20

… and few other elements account for most of the remaining 4% of an organism’s mass
A) Calcium, Potassium, Copper and Sulphur
B) Calcium, Phosphorus, Potassium and Sulphur

Answer 20

B

Question 21

… elements are required by an organism only in minute quantities

Answer 21

Trace elements

Question 22

Some trace elements such as … are required by all forms of life
A) Iron
B) Krypton
C) Potassium

Answer 22

Iron (Fe)

Question 23

Vertebrates are animals?
A) With backbone
B) Without backbone

Answer 23

A

Question 24

In Vertebrates the element … is an essential ingredient of a hormone
A) Iodine
B) Thyroxin

Answer 24

A

Question 25

In vertebrates … element is an essential ingredient of a hormone produced by … gland A) Cu and thyroid gland B) Iodine and thyroid gland

Answer 25

B

Question 26

Daily intake of … mg of iodine is adequate for normal activity of human thyroid A) 0.5 mg B) 0.15 mg C) 0.51 mg

Answer 26

B

Question 27

Which element deficiency causes goiter? A) iodine B) thyroid

Answer 27

A

Question 28

In goiter thyroid gland becomes? A) Abnormally large B) Abnormally small

Answer 28

A

Question 29

What lessens the chances of goiter? A) Taking seafood or iodised salt B) Consuming fresh fruits or iodised salt

Answer 29

A