Unit #2 Physical & Chemical Properties



Unit #2 Physical & Chemical Properties

Study Sheets with Answers

Grade 9 SNC 1D1

1. What is a property?

A property is a characteristic that can be used to describe something.

2. What is a physical property?

Physical properties are characteristics that can be observed without changing the chemical composition (make-up) of matter. In other words, without creating a new particle.

3. What is a qualitative physical property?

A qualitative physical property is a characteristic of a substance that can be described but not measured.

4. List the 9 most common qualitative properties and describe each.

State: Solid, liquid or gas.

Colour: Red, orange, yellow, green, blue, etc.

Clarity: Transparent, translucent, or opaque.

Lustre: The ability of a object to reflect light (shiny/dull)

Texture: The feel of a substance (rough/smooth)

Odour: Odourless, burnt, flowery, spicy, nauseating, suffocating.

Brittleness: The ability of an object to break or shatter. A substance which bends without breaking is said to be flexible.

Malleability: The ability of a substance to be hammered into a sheet.

Viscosity: The resistance of a liquid to flow. (thick/thin/runny/syrupy)

5. What is a quantitative physical property.

A quantitative physical property is a characteristic of a substance that can be measured numerically.

6. List the 7 most common quantitative physical properties and describe each.

|Hardness |The resistance to being scratched, rated on a scale of 1-10 (flour-1, glass-5, diamond-10) |

|Density |The ratio of mass to volume for a substance. (eg. 1.00g/mL |

|Boiling Point |The temperature at which a liquid turns into a gas. (eg. Water 100 C) |

|Freezing Point |The temperature at which a liquid turns into a solid. (eg. Water 0 C) |

|Solubility |The mass of a solid that will dissolve in a given amount of liquid at a fixed temperature. (eg. 50g/1000 |

| |g of water) |

|Electrical Conductivity |The ability of a substance to conduct electricity. |

|Heat Conductivity |The ability of a substance to conduct heat. |

7. What is a chemical property?

A chemical property is a characteristic of a substance describing how it reacts when it is involved in a chemical change.

8. List three examples of a chemical property and describe each.

a. Natural gas burns with a blue flame.

b. Steel will rust when exposed to rainy weather.

c. Sodium reacts violently to water.

d. Hydrochloric acid is corrosive to the skin.

9. What is the formula for volume?

Volume = l x w x h

10. What is density?

Density is the measure of the amount of matter per unit volume. The S.I. unit for density is the kilogram per cubic metre (kg/m3)

11. What is the formula for density?

Density = mass m D= m V = m

Volume OR v d

V D m = V x D

12. What is the density for distilled water?

The density of distilled water is 1.00g/cm3)

13. Different samples of matter have different densities.

14. Calculate the density of 100g sample of matter which occupies 200L of space.

Solution:

Let D represent the density of the sample.

Given: 1) m= 100g Then: D = 100g

2) V= 200L 200L

3) D= m/V =0.5g/L

Since: D = m Therefore the density of the

V sample is 0.5g/L

15. What did the ancient Greek philosopher Empedocies believe?

Empedocies suggested that all matter was composed of four elements. (Earth, fire, air, and water)

16. What did the ancient Greek philosopher Democritus believe?

Democritus stated that all matter was made up of tiny indivisible particles which he called atomos.

17. What are the 5 points of John Dalton’s Atom Theory?

John Dalton’s Atomic Theory

1. Matter is made up of indestructible particles called atoms.

2. Atoms of the same elements are identical.

3. Atoms of different elements have different properties.

4. Atoms combine to form molecules.

5. During chemical reactions, atoms are neither created nor destroyed, they only join or separate.

18. Who discovered the electron?

During the late 1800’s, an English scientist, J.J. Thomson discovered a particle with a negative charge; the electron.

19. Draw Thomson’s Model of the Atom.

20. What is this diagram sometimes compared to? Why?

Some people see fit to compare Thomson’s atom to a blueberry muffin in which the negatively charged electrons (blueberries) are embedded in a lump of positively charged protons (muffin).

21. Draw and label Rutherford’s Gold Foil Experiment.

[pic]

22. What are the results of this experiment?

|Observation |Inference |

|Most of the alpha particles pass straight through the gold foil |The gold atoms are made up of empty space. |

|completely undisturbed. | |

|Some alpha particles were deflected slightly off their straight |The positively charged centres in the gold atoms repelled the |

|line path. |positively charged alpha particles. |

|Some particles bounced back in the direction from which they |There must be a small hard region at the centre of the atom. |

|originated. |Rutherford called this region the nucleus. |

23. List the 4 points of the Rutherford Atom Theory.

The Rutherford Atom

1. The atoms is made up of mostly empty space.

2. All the mass of the atom is located in the central region call the nucleus.

3. The nucleus contains a positive charge.

4. Negatively charged particles called electrons circle the nucleus, much like planets circle the Sun.

24. What did Niels Bohr discover while working with Rutherford? List 3 points.

1. Electrons move in circular orbits around the nucleus.

2. The electron of an atom does not move into the nucleus of an atom because it has a fixed, or quantized amount of energy.

3. An electron moves into the next energy level if it gains energy.

25. Who discovered the neutron?

The neutron was discovered by Sir James Chadwick, another British scientist, in 1932.

26. What are 4 points included in the Bohr-Rutherford Model of the Atom.

The Bohr-Rutherford Model of the Atom

1. Atoms are very small

2. The mass of an electron is very small compared to the mass of the entire atom.

3. The electrons exist in energy levels outside the nucleus.

4. Atoms are made up of charged particles.

27. Make a chart summarizing sub-atomic particles.

|Particle |Charge |Mass |Location |

|Proton |1+ |1u |Nucleus |

|Electron |1- |1/1837u |Orbit |

|Neutron |0 |1u |Nucleus |

28. What is isotopic notation?

29. What is an atomic number?

The number can be used to identify the element.

It indicates the number of protons and elections

that are present in 1 atom which contains

both 9 protons and 9 electrons.

30. What is a neutral atom number?

A neutral atoms is an atoms which has the same number of protons and electrons.

31. What is the mass number?

This number indicated the number of the particles that are present the nucleus of 1 atom of the element. Since the protons and neutron exist in the nucleus, this number in the number of protons + the number of neutrons.

32. Draw the Bohr-Rutherford Diagram for the first 20 elements.

33. How many groups are there in the periodic table? How are these groups divided?

The Periodic table is divided into 18 vertical groups (columns).

34. How many periods are the in the periodic table? How are these periods divided?

The Periodic table is divided into 7 horizontal periods (rows). The first period (comprised of hydrogen and helium) have only 1 orbit of electrons. The second period have 2 orbits, and so on.

35. What is the purpose of the diagonal staircase on the right side of the table?

This diagonal staircase separates the metal from the non-metals. Metallic elements can be found on the left, while the non-metallic elements, the right. Also, a third category, metalloids, (element with properties of both metals and non-metal) can be distinguished, they are connected by one side to the staircase.

36. How are the states of elements (at room temperature) distinguished, on a Periodic Table?

Solid are represented by white or black

Liquids are represented by blue

Gases are represented by red

37. What is an ion?

An ion is a charged particle which is created when a neutral atom gains or loses electrons. When this happens, the number of protons in the nucleus differs from the number of electrons in the orbits for that particle.

38. What are cations?

Cations are positively charged particles; particles which have lost electrons.

39. What are anoins?

Anions are negatively charged particles; particles which have gained electrons.

40. How would you go about drawing a Bohr-Rutherford Diagram for Ions?

|[pic] |- 1 electron |[pic] |

|Li |Vs. |Li1+ |

|[pic] |+3 |[pic] |

| |electrons | |

|N |Vs. |N3- |

41. Elements with similar Bohr-Rutherford Diagrams have similar properties.

42. Why is group VIIIA elements special?

Group VIIIA elements have a complete outer energy level, and as a result, they are generally inactive.

43. What are group IA Elements classified as? Which element belong in group IA? Why are they all grouped together?

IA Elements are known are the Alkali-Metals. They include Li, Na, K, Rb, Cs, and Fr. All IA elements have one electron in their outer most energy orbit.

44. What are similar physical and chemical properties between these elements?

|Similar Physical Properties |Similar Chemical Properties |

|All solids are rooms temperature |All react with oxygen in air and must be stored in oil |

|All silver in colour |All react with water to produce gas and a base |

|All lustrous |All react with chlorine to produce salt compounds |

|All conduct electricity |All react with oxygen to produce oxide compounds |

45. What are group IIA Elements classified as? Which element belong in group IIA? Why are they grouped together?

Group IIA are known as Akaline-Earth Metals. They include Be, Mg, Ca, Sr, Ba, Ra. They are grouped together because they are have two electrons in their outer most energy orbit.

46. What are similar physical and chemical properties between these elements?

|Similar Physical Properties |Similar Chemical Properties |

|All solids at room temperature | All react with oxygen to form oxide coating |

|All conduct electricity |All react with water (at different rates) to produce bubbles |

|Not stored in oil |All react with acids (at different rates) to produce bubbles |

|All coated with an oxide but shiny when oxide is removed | |

|All silver in colour | |

| | |

47. What are group VIIA Elements classified as? Which element belong in group VIIA?

Group VIIA Elements are known as Halogens. They include F, Cl, Br, I, At. They are grouped together because they all have 7 electrons in their outer most energy orbit.

48. What are similar physical and chemical properties between these elements?

Physical Properties

|Fluorine |A pale yellow gas at room temperature |

|Chlorine |A yellowish-green gas with a corrosive odour at room temperature |

|Bromine |A reddish- orange liquid at room temperature. This liquid readily vaporizes to produce a corrosive |

| |gas. |

|Iodine |A purplish-black solid at room temperature. This solid readily vaporizes to produce a purpose gas. |

|Astatine |A black solid at room temperature. |

Chemical Properties

• All halogens reacts with IA or IIA elements to produce compounds called halides.

49. What are group VIIIA Elements classified as? Which element belong in group VIIIA?

Group VIIA Elements are known as Inert Gases. They include He, Ne, Ar, Kr, Xe, Rn. They are grouped together because their outer most energy orbit is completely filled.

50. What are similar physical and chemical properties between these elements?

|Similar Physical Properties |Similar Chemical Properties |

|All are colour less gases at room temperature |All are generally unreactive elements. |

51. What is a chemical family?

Elements which have similar chemical and physical properties.

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