a1.1.4 - adhesion

Question 1

define adhesion

Answer 1

the force by which individual molecules stick to surrounding materials and surfaces

Question 2

define polarity

Answer 2

unequal sharing of electrons in a covalent bond between two atoms
- a molecule has two different electrical charges

Question 3

define ion

Answer 3

an atom with different (unequal) numbers of electrons and protons

Question 4

compare cation and anion

Answer 4

cation - has a positive charge because it has more protons than electrons (Na+)
anion - has a negative charge because it has more electrons than protons (Cl-)

Question 5

explain why water is attracted to molecules that are polar or charged

Answer 5

• the slight negative charge (δ-) of oxygen atom is attracted to the slight positive charge of the molecules that are polar or charged
• the slight positive charge (δ+) of hydrogen atom is attracted to the slight negative charge of molecules that are polar or charged

Question 6

define capillary action

Answer 6

the movement of water in through a narrow space, often in opposition to external forces like gravity

Question 7

outline the cause of capillary action

Answer 7

adhesion of water to the walls of the vessel will cause an upward force on the liquid.

Question 8

describe the capillary action in plant tissue

Answer 8

capillary action helps bring water from the roots all the way up to the branches and leaves. Adhesion of water to the xylem walls will cause an upward force on the water.

Question 9

outline the cause and effect of capillary action in soil

Answer 9

capillary action in soil is the primary force that enables the soil to retain water. in the same way that water moves upwards through a tube against the force of gravity; water moves upwards through soil pores, or the spaces between soil particles.