Book 2: Classifying Matter

Name:__________ Block:_____

Chemistry 11

A material’s _________________________________ is the temperature of its solid as it changes to a liquid. Melting occurs because the independent particles have spread far enough ___________so that they can just slip through the gaps between the atoms surrounding them. The melting point of a substance depends on the___________________ of the attractive forces (___________________________) between the particles as well as the mass and symmetry of the particles. The _______________________________and melting point of most substances are the same.

Some Physical Properties of Pure Substances

Melting Point

Figure 2.1.5 At the melting point, a substance can exist in both the solid and liquid states.

Boiling Point Boiling is a special case of ________________________________. Any particle in the liquid state may evaporate. The puddles on your street evaporate but you’ve never seen a puddle boil. The gas formed by a substance that boils above room temperature is called ___________________________.

____________________________________ is the vigorous bubbling that occurs within the body of a liquid as it ________________________________ internally. A bubble is a quantity of gas or vapour surrounded by liquid. _______________________________________is also defined as a substance’s highest possible temperature in the liquid state at any given atmospheric pressure. It therefore represents the highest _________________________________the substance’s particles can possess in the liquid state. As the temperature of the water approaches 100°C, more and more of the molecules have their ______________________kinetic energy in the liquid state until at 100°C all the molecules are ________________________ at the same ________________________________________________in the liquid state.

Figure 2.1.6 Vigorously boiling water. The bubbles are rising to the surface without collapsing.

Boiling point, vapour pressure, and volatility are three closely related properties that are all relevant to boiling. _______________________________ substances are substances that _________________________ or evaporate at high rates. They have __________________vapour pressures and ____________________ boiling points. Heat of Fusion (Hf ) The heat of fusion is the amount of _________________ _____________________ a specified amount of a substance at its melting point. It represents the difference of _______________ _______________ between the solid and liquid states since only the substance’s state, not its temperature, is changing. Potential energy is ____________ energy in the b_________. The heat of fusion is released when the specified quantity of the substance freezes. Heat of fusion is measured in ________________________________.

Heat of Vaporization (Hv) (measured in joules/gram)

The heat of vaporization is the amount of heat required to _________________________a specified amount of a substance at its boiling point. It represents the difference of potential energy between the ____________ and ________ states since only the substance’s state, not its temperature, is changing. The heat of vaporization is released when the specified quantity of the substance ____________________. The heat of vaporization indicates the _________________of the force holding the liquid ______________________________________in the liquid state.

Quick Check

1. What is melting? __________________________________________________________________________

2. What is boiling? ___________________________________________________________________________

3. What is the heat of fusion? ___________________________________________________________________

Reading a Heating Curve

As ______________is added to a solid, the __________________________________ changes. These changes in temperature can be illustrated in a graph called a ____________________ ______________. Figure 2.1.7 illustrates an ideal heating curve for water. Note the first plateau in the graph. As a solid melts slowly in its own liquid, the temperature of the liquid will ______________ if the melting converts ____________________ energy into ___________________energy as fast as the ____________is being added. As the amount of solid decreases, it becomes less able to remove the heat as fast as it is being added. This usually causes the melting segment on the graph to curve upward on the right, rather than remaining horizontal as shown on the ideal heating curve (Figure 2.1.7). The amount of heat needed to melt the ice is the_________________________. Once all the ice has melted the water’s temperature will begin to_____________________.

Temperature vs. Added Heat

HvHf

Added Heat(joules)

Tem

pera

ture

(ºC)

0

100

(s)

(l)

(g)boiling

melting

Figure 2.1.7 Ideal heating curve of a pure substance

Temperature vs. Added Heat

HvHf

Added Heat(joules)

Tem

pera

ture

(ºC)

0

100

Figure 2.1.8 Ideal heating curve of a mixture

8. State whether each of the following properties isphysical or chemical.

(a) heat of vaporization

(b) heat of formation

(c) corrosion resistance

(d) electrical resistance

(e) flammability (how easily something will burn orignite)

(f ) speed of sound through the material

9. Composite materials (or just composites) consist oftwo or more constituent materials that adhere toeach other but remain separate and distinct (e.g. thematerials could be layered on each other). Why doyou think manufacturers sometimes use compositematerials in their products?

10. What two properties of particles affect thetemperature of the material they compose?

11. Density is mass per unit volume, commonly theamount of matter in one cubic centimetre of thematerial. What two properties of particles affect thedensity of the material they compose?

12. Briefly explain what causes materials to expand atthe particle level when heated.

13. List the defining physical properties of each phaseof matter; solids, liquids, and gases.

14. Does an individual atom or molecule have a meltingpoint? Explain.

15. Describe what is occurring at the molecular levelwhen a material melts.

16. Why doesn’t the temperature of an ice water bath (amixture of ice and water) increase as it absorbs heatfrom a classroom?

Review Questions (complete the following questions in this workbook)

17. Under what condition do all the particles of a liquidhave the same kinetic energy?

18. Provide an operational (what to look for) and aconceptual (an explanation) definition of boilingpoint.

19. (a) Which is greater, a substance’s heat of fusion orits heat of vaporization?

(b) Explain in terms of relationships why this would be expected.

20. (a) Which is greater, a substance’s heat ofvaporization or its heat of combustion?

(b) Explain in terms of relationships why this would be expected.

21. Sensorial properties describe our senses of amaterial. Rather than being the properties ofsomething, they are actually the properties of ourinteraction with that thing. Are sensorial propertiessuch as taste and odour physical properties or arethey chemical properties?

22. Label and describe briefly a physical change and achemical change on the drawing of the lit candle.

23. Students change classes at designated timesthroughout the day in most secondary schools. Howis this event like a chemical change or reaction?

2.2 The Classification of Matter

Warm UpMost sentences or paragraphs in your textbooks could be classified as a definition, a description, an explanation, a comparison, a sequence, an example, or a classification.

1. Give an example of a sport. ___________________________________

2. Name a class of sports. ___________________________________

3. What is the difference between an example of something and a class of something?

___________________________________________________________________________

Classifying MatterWe currently classify everything in the physical world as either a form of _________________or a form of _____________. Any solid, liquid, or gas is a form of matter. Matter can be further classified as shown:

������Figure 2.2.1 Classification of matter

Material Definition Examples

pure substance

mixture

element

atom

Molecule

Ion

Compound

Particle

The particles that make up materials are also forms of matter. Chemists refer to all the particles of matter collectively as _____________________________________ Just as materials are classified, so are chemical species. Chemical species can be classified as neutral _________, _______________________, or ____________. Atoms are composed of particles that can be classified as well.

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ElementsFigure 2.2.2 Classification of elements

The elements are further classified as metals, non-metals, and metalloids.About __________ of the elements are metals.

____________________ has properties that are in-between those of the metals and the non-metals. Although it has some chemical properties of metals, it has more in common with non-metals and is classified as a ____________________for most purposes. Hydrogen is such a unique element that it is usually considered to be in a group of its own.

1H

30Zn

48Cd

80Hg

5B

13Al

31Ga

49In

81Tl

6C

14Si

32Ge

50Sn

82Pb

7N

15P

33As

51Sb

83Bi

8O

16S

34Se

52Te

84Po

9F

17Cl

35Br

53I

85At

2He

10Ne

18Ar

36Kr

54Xe

86Rn

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Figure 2.2.3 The location of metals, non-metals,

and metalloids in the periodic table of the elements

Metals are good _____________________of both __________ and ____________________. They are also __________ (can be pounded into thin sheets),__________(can be drawn into wires), and __________. __________, mixtures containing metals, which are hard. Metal oxides react with water to form __________(hydroxides). For example:Na2O + H2O → 2 NaOH

Non-metals are __________conductors of both heat and electricity. Many are __________ at room temperature but in the solid phase their crystals are __________and shatter easily. Non-metal oxides react with water to form __________. For example: CO2 (g) + H2O(l) → H2CO3 (aq) (carbonic acid)

Moving up and to the __________in the periodic table, there is a general trend toward ____________________metallic character from one element to the next. As a consequence, there is no sharp demarcation between the metals and non-metals. Instead, there is a group of elements called ____________________ that exhibit some metallic properties (although weakly) and some non-metallic properties. For example, __________ is a semiconductor meaning that it conducts electricity but poorly.

CompoundsA compound of matter is a____________________composed of more than one type of __________. A compound can be decompounded (we say decomposed). ____________________ is a type of chemical reaction in which a single compound reacts to produce ______________________________substances. They reassemble into two or more new groupings or patterns of the atoms.

2NaCl → 2Na + Cl2K2CO3 → K2O + CO22H2O → 2H2 + O2

Compounds are classified in several ways. An organic compound is any compound that has carbon and hydrogen atoms. It may have other types of atoms as well. All other compounds are____________________ meaning not organic. A binary compound is composed of only __________ elements. Hydrocarbons (compounds consisting of only carbon and hydrogen atoms) are thus binary compounds whereas carbohydrates are non-binary compounds because they contain carbon, hydrogen, and oxygen atoms.

An__________is a charged atom or group of atoms. Because ions are more stable than their corresponding neutral atoms, the atoms of many elements exist almost exclusively in nature as ions. Ionic compounds consist of positively and negatively charged ions held together by their opposite electrical charges into long range, symmetrical packing arrangements called ionic crystal lattices (Figure 2.2.4). The bond or attraction between oppositely charged ions is appropriately called an ionic bond.

Na+Cl-

Figure 2.2.4 An ionic crystal lattice Figure 2.2.5 A molecular compound

Non-metal atoms can also become more stable by sharing valence (outer) electrons with each other, called a ___________________________ bond. A neutral group of covalently bonded atoms is called a __________________ and compounds consisting of molecules are called molecular compounds.

Any compound containing a metal is an_______________________________.

Any compound containing only non-metals is a _________________________________________ except compounds containing the ammonium ion (NH4

+) which are ionic.

Sample Problem — Classifying a Compound as Ionic or Molecular

State whether each of the following is an ionic compound or a molecular compound:(a) NaCl (b) Cu(NO3)2 (c) P2O5

What to Think aboutIf the compound contains a metal or the ammonium ion then it is ionic, otherwise it is molecular.(a) Na is a metal(b) Cu is a metal(c) P and O are both non-metals

How to Do It

(a) NaCl is an ionic compound. (b) Cu(NO3)2 is an ionic compound. (c) P2O5 is a molecular compound.

Practice Problems — Classifying a Compound as Ionic or Molecular

1. State whether each of the following is an ionic compound or a molecular compound:

(d) Mg3(PO4)2 ________________________ (a) CO2 ________________________

(b) CaF2 ________________________

(c) C3H8 ________________________

(e) Li2Cr2O7 ________________________

(f ) NH4Cl ________________________

Classifying Matter Worksheet

Classify each of the materials below. In the center column, state whether the material is a pure substance or a mixture. If the material is a pure substance, further classify it as either an element or compound in the right column. Similarly, if the material is a mixture, further classify it as homogeneous or heterogeneous in the right column.

Material Pure Substance or Mixture

Element, Compound, Homogeneous, Heterogeneous

concrete sugar + pure water (C12H22O11 + H2O)

iron filings (Fe)

limestone (CaCO3)

orange juice (w/pulp)

Pacific Ocean

air inside a balloon

aluminum (Al)

magnesium (Mg)

acetylene (C2H2)

tap water in a glass

soil

pure water (H2O)

chromium (Cr)

Chex mix salt + pure water

(NaCl + H2O) benzene (C6H6)

muddy water brass

(Cu mixed with Zn) baking soda (NaHCO3)