Why does an instant cold pack feel cold when ammonium nitrate (NH 4 NO 3 ) dissolves in water?

The dissolution is exothermic and gives off heat to the hand

The dissolution is an ideal solution with no net enthalpy change

Ammonium nitrate reacts chemically with water to freeze the pack

የምዕራፍ ማስታወሻዎችና የመልመጃ ጥያቄዎች

የ10ኛ ክፍል ኬሚስትሪ ምዕራፍ 2፦ ሶሉሽኖች

በዚህ ገጽ ያለው ሁሉ ለ10ኛ ክፍል የኬሚስትሪ መፅሐፍ ምዕራፍ 2 ነው፦ ምዕራፉ የሚሸፍነው፣ አጭር ማስታወሻዎቹ፣ የመልመጃ ጥያቄዎች ከመልሶቻቸው ጋር፣ እና ቪዲዮ ባለበት የትምህርቱ ቪዲዮ።

4
ካርዶች: 10
የምዕራፍ 2 የመልመጃ ጥያቄዎች: 51–110
የምዕራፍ 2 የመፅሐፍ ገጾች

ምዕራፍ 2 የሚሸፍነው

1.Heterogeneous and Homogeneous Mixtures
2.The Solution Process
3.Solubility as an Equilibrium Process
4.Ways of Expressing Concentration of Solution
5.Preparation of Solutions
6.Solution Stoichiometry

የምዕራፍ 2 አጭር ማስታወሻዎች

በ10ኛ ክፍል የኬሚስትሪ ገጽ ላይ በዚህ ምዕራፍ ሥር የተመዘገቡት ካርዶች። አንድ በአንድ ይክፈቱ።

የኮሎይዶች ምደባየማጣቀሻ ሠንጠረዥፈሳሽ · ጠጣር · ጋዝ

የተበተነው ክፍል	የሚበትነው አካል	የኮሎይድ ዓይነት	ምሳሌ
ፈሳሽ	ጋዝ	Aerosol	ጉም፣ ደመና፣ ጭጋግ
ጠጣር	ጋዝ	Aerosol	ጢስ፣ የተሽከርካሪ ጭስ (exhaust)
ጋዝ	ፈሳሽ	Foam	የጺም መላጫ ክሬም (Shaving cream)
ፈሳሽ	ፈሳሽ	Emulsion	ወተት፣ የፊት ክሬም
ጠጣር	ፈሳሽ	Sol	Milk of magnesia
ጋዝ	ጠጣር	Foam	ስፖንጅ፣ ፑሚስ (pumice)
ፈሳሽ	ጠጣር	Gel	ጄሊ፣ አይብ፣ ቅቤ
ጠጣር	ጠጣር	Solid sol	የከበረ ድንጋይ (Gemstone)፣ ወተታማ መስታወት (milky glass)

መቼ እንደሚጠቀሙበት

የተበተነውን እና የሚበትነውን አካል የቁስ ሁኔታ መሠረት በማድረግ የኮሎይድ ዓይነቶችን ለመለየት ይጠቀሙበት።

ይጠንቀቁ

ጋዝ በጋዝ ውስጥ ሲበተን ኮሎይድ አይፈጥርም፤ ሁሉም ጋዞች ሙሉ በሙሉ ተቀላቅለው እውነተኛ መፍትሔ (solution) ይፈጥራሉ።

ከGrade 10 Chemistry፣ ገጽ 51-110 የተዘጋጀ፤ ከመውጣቱ በፊት ሁለት ጊዜ ተረጋግጧል

የአዮኒክ ድፍን የመፍትሔ ኢንታልፒቀመር

\Delta H_{\text{soln}} = \Delta H_{\text{lat}} + \Delta H_{\text{hydr}}

\Delta H_{\text{soln}} = \Delta H_{\text{lat}} + \Delta H_{\text{hydr}}

$\Delta H_{\text{soln}}$: የመፍትሄ ሞላር ኢንታልፒ $\text{kJ}\,\text{mol}^{-1}$
$\Delta H_{\text{lat}}$: የላቲስ ኢነርጂ $\text{kJ}\,\text{mol}^{-1}$
$\Delta H_{\text{hydr}}$: የሃይድሬሽን ኢንታልፒ $\text{kJ}\,\text{mol}^{-1}$

መቼ እንደሚጠቀሙበት

አዮኒክ ድፍን በውሃ ውስጥ ሲሟሟ የሚኖረውን ጠቅላላ የሙቀት ለውጥ ከlattice እና hydration energies ለማስላት ይጠቀሙበት።

ይጠንቀቁ

Lattice energy ሁልጊዜ ፖዘቲቭ (endothermic) ሲሆን፣ hydration energy ደግሞ ሁልጊዜ ኔጌቲቭ (exothermic) ነው።

ከGrade 10 Chemistry፣ ገጽ 51-110 የተዘጋጀ፤ ከመውጣቱ በፊት ሁለት ጊዜ ተረጋግጧል

የመፍትሔ ሙቀትቀመር

q = m C_g \Delta T

q = m C_g \Delta T

$q$: የተለቀቀ ወይም የተመጠጠ ሙቀት $\text{J}$
$m$: የመፍትሄው መጠነ ቁስ $\text{g}$
$C_g$: የመፍትሄው ልዩ የሙቀት አቅም $\text{J}\,\text{g}^{-1}\,{^{\circ}\text{C}}^{-1}$
$\Delta T$: የሙቀት መጠን ለውጥ $^{\circ}\text{C}$

መቼ እንደሚጠቀሙበት

በካሎሪሜትር ውስጥ በሚሟሟበት ጊዜ የተወሰደውን ወይም የተለቀቀውን ጠቅላላ ሙቀት ለማስላት ይጠቀሙበት።

ይጠንቀቁ

ግዝፈቱ m የሟሚው እና የማሟሟያው ድምር ክብደት (total solution mass) መሆን አለበት፤ የማሟሟያው ብቻ አይደለም።

ከGrade 10 Chemistry፣ ገጽ 51-110 የተዘጋጀ፤ ከመውጣቱ በፊት ሁለት ጊዜ ተረጋግጧል

የሄንሪ ሕግቀመር

C = k P

C = k P

$C$: የተሟሟ ጋዝ ክምችት $\text{mol}\,\text{L}^{-1}$
$k$: የHenry ህግ ቋሚ $\text{mol}\,\text{L}^{-1}\,\text{atm}^{-1}$
$P$: የጋዙ ከፊል ግፊት $\text{atm}$

መቼ እንደሚጠቀሙበት

የአንድ ጋዝ በተወሰነ partial pressure ውስጥ በፈሳሽ ውስጥ ያለውን solubility ወይም concentration ለማስላት ይጠቀሙበት።

ይጠንቀቁ

ከውሃ ጋር በኬሚካል የሚገናኙ ወይም hydrogen bond የሚፈጥሩ ጋዞች ለምሳሌ HCl እና NH3 የሄንሪን ሕግ አይከተሉም።

ከGrade 10 Chemistry፣ ገጽ 51-110 የተዘጋጀ፤ ከመውጣቱ በፊት ሁለት ጊዜ ተረጋግጧል

የምዕራፍ 2 የመልመጃ ጥያቄዎች

በዚህ ምዕራፍ ላይ የተጻፉ 10 የምርጫ ጥያቄዎች፣ እያንዳንዳቸው መልሱና ምክንያቱ አላቸው። መልሱን ከመክፈትዎ በፊት ይሞክሩ። ጥያቄዎቹ በእንግሊዝኛ ናቸው።

ጥያቄ 1

What is the particle size range in a colloidal solution?

A.Less than 0.1 nm
B.Between 1 nm and 100 nm
C.Between 200 nm and 500 nm
D.Greater than 1000 nm

መልሱንና ምክንያቱን ያሳዩ

መልስ፦ B Between 1 nm and 100 nm

ምክንያቱ

According to the textbook, the size of particles in a colloid is between 1 nm and 100 nm in diameter. This makes them larger than particles in a true solution but smaller than those in a suspension.

ጥያቄ 2

According to the textbook classification of colloids, milk and face cream are examples of which type?

A.Aerosol
B.Gel
C.Emulsion
D.Sol

መልሱንና ምክንያቱን ያሳዩ

መልስ፦ C Emulsion

ምክንያቱ

An emulsion is a type of colloid where a liquid is dispersed in another liquid. Milk and face cream are both classified as liquid in liquid emulsions.

ጥያቄ 3

Which type of mixture has a single uniform phase with no visible boundaries because its components are mixed as individual atoms, ions, or molecules?

A.Homogeneous mixture (solution)
B.Suspension
C.Heterogeneous mixture
D.Coagulated mixture

መልሱንና ምክንያቱን ያሳዩ

መልስ፦ A Homogeneous mixture (solution)

ምክንያቱ

A homogeneous mixture, also called a solution, has a uniform composition throughout with no visible boundaries because the components are mixed at the atomic, molecular, or ionic level.

ጥያቄ 4

What happens to the solubility of most gases in liquid solvents when the temperature increases?

A.Solubility increases
B.Solubility decreases
C.Solubility stays completely unchanged
D.Solubility doubles

መልሱንና ምክንያቱን ያሳዩ

መልስ፦ B Solubility decreases

ምክንያቱ

The solubility of gases in liquids decreases with increasing temperature because added heat breaks the attractive forces between gas molecules and solvent molecules, causing the gas to escape.

ጥያቄ 5

How are the stearate ions arranged when soap forms an association colloid (micelle) in water?

A.Hydrophilic ends point inward and nonpolar tails face the water
B.Hydrophobic hydrocarbon ends point inward and hydrophilic carboxyl groups face outward toward water
C.Both ends point inward away from the water
D.Both ends face outward toward the water

መልሱንና ምክንያቱን ያሳዩ

መልስ፦ B Hydrophobic hydrocarbon ends point inward and hydrophilic carboxyl groups face outward toward water

ምክንያቱ

In water, soap forms micelles where the nonpolar (hydrophobic) hydrocarbon tails turn inward to avoid water and trap oil, while the ionic carboxyl groups (hydrophilic) face outward toward the polar water molecules.

ጥያቄ 6

Based on the solubility rules for ionic solids in the textbook, which of the following compounds is insoluble in water?

A.AgNO3
B.KI
C.BaCO3
D.AlCl3

መልሱንና ምክንያቱን ያሳዩ

መልስ፦ C BaCO3

ምክንያቱ

Carbonates (CO₃^2-) are insoluble in water, except those of Group 1A elements and ammonium. Since barium (Ba) is in Group 2A, BaCO₃ is insoluble. Nitrates, Group 1A salts (like KI), and most chlorides are soluble.

ጥያቄ 7

Which step of the solution formation process is exothermic?

A.Separation of solute particles from one another
B.Separation of solvent particles from one another
C.Mixing of solute and solvent particles to form solute-solvent attractions
D.Overcoming the crystal lattice energy of the solid

መልሱንና ምክንያቱን ያሳዩ

መልስ፦ C Mixing of solute and solvent particles to form solute-solvent attractions

ምክንያቱ

Breaking solute-solute or solvent-solvent attractions requires energy and is endothermic. Forming new attractive solute-solvent interactions releases energy, making step 3 exothermic (ΔH_mix < 0).

ጥያቄ 8

Why does an instant cold pack feel cold when ammonium nitrate (NH₄NO₃) dissolves in water?

A.The dissolution is exothermic and gives off heat to the hand
B.The dissolution is endothermic and absorbs heat from the surroundings
C.The dissolution is an ideal solution with no net enthalpy change
D.Ammonium nitrate reacts chemically with water to freeze the pack

መልሱንና ምክንያቱን ያሳዩ

መልስ፦ B The dissolution is endothermic and absorbs heat from the surroundings

ምክንያቱ

Dissolving ammonium nitrate in water is an endothermic process. It absorbs heat from the surroundings, causing the temperature of the pack to drop significantly.

ጥያቄ 9

In a bottled soft drink in Hawassa, the concentration of dissolved CO₂ is 0.032 M at a partial pressure of 3.0 atm. What is the concentration of dissolved CO₂ if the pressure is increased to 6.0 atm at constant temperature?