Complete the statements based on water’s polarity and ability to form hydrogen bonds. water’s boiling point is abnormally than expected. water has a surface tension, allowing adhesion, cohesion, and capillary action. water has a capacity to retain heat, keeping moderate climates warmer in the winter. water as it freezes, so ice floats when expected to sink. answers are higher high high expands

1 Higher

2 High

3 High

4 Expands

Explanation:

a) Water's boiling point is abnormally higher than expected

b) Water has a high surface tension allowing adhesion, cohesion and capillary action.

c) Water has a high capacity to retain heat, keeping moderate climates warmer in the winter.

d) Water expands as it freezes, so ice floats when expected to sink.

Explanation:

a) Because of its small molecular weight, it's expected that the water has a low boiling point, but the abillity to make hydrogen bonds generates an atraction force between the molecules much more stronger that expected.

This phenomenom implies that the water has higher boiling point than other heavier compounds.  

b) The high surface tension its the result of the hydrogen bonds and the polarity of the water molecules, giving the water molecules stronger bonds and like a very strong net, makes it harder to get through.

This is the cause of the listed phenomena: cohesion, adhesion and capillary action.

c) Another effect of the hydrogen bonds of the water is its high thermal capacity.

The hydrogen bonds are the strongest of the molecular bonds (H bonds, dipole-dipole and London) and the stronger the bond is, the higher the amount of energy (in this case heat) it can absorb before its rupture.

This is why water have a high thermal capacity compared with other molecules that only have London or dipole bonds.

d)  Water expands when it freezes because the molecules rearrange and during that, many of the hydrogen bonds break.

When that happens, the water molecules have a weaker attraction than before and in consecuence the water (ice) expands.

Also, ice floats beacuse once it expands it has a lower density compared to the water.

the atomic mass is the bottom number on the element.

-steel jelly

when 25.0 ml of 0.700 mol/l naoh was mixed in a calorimeter with 25.0 ml of 0.700 mol/l hcl, both initially at 20.0 °c, the temperature increased to 22.1 °c. the heat capacity of the calorimeter is 279 j/°c.

the equation for the reaction is:

naoh + hcl → nacl + h₂o

moles of hcl = 0.0250 l hcl ×

0.700

mol hcl

1 l hcl = 0.0175 mol hcl

volume of solution = (25.0 + 25.0) ml = 50.0 ml

mass of solution = 50.0 ml soln ×

1.00

ml soln

= 50.0 g soln

δt=t2-t1

= (22.1 – 20.0) °c = 2.1 °c

the heats involved are

heat from neutralization + heat to warm solution + heat to warm calorimeter = 0

q1+q2+q3=0

nδh+mcδt+cδt=0

0.0175 mol ×

δh

+ 50.0 g × 4.184 j·g⁻¹°c⁻¹ × 2.1 °c + 279 j°c⁻¹ × 2.1 °c = 0

0.0175 mol ×

δh

+ 439.32 j + 585.9 j = 0

0.0175 mol ×

δh

= -1025.22 j

δh=1025.22j0.0175 mol= -58 600 j/mol = -58.6 kj/mol