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# Objective 4: Structures and Properties of Matter PowerPoint PPT Presentation

Objective 4: Structures and Properties of Matter. IPC 7A – Investigate and identify properties of fluids including density, viscosity and buoyancy. Density. Density = mass volume D = M V. Math Tip for Density. D =. M. 1. V. Cross Multiply. Buoyancy.

Objective 4: Structures and Properties of Matter

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## IPC 7A – Investigate and identify properties of fluids including density, viscosity and buoyancy.

Density = mass

volume

D = M

V

D =

M

1

V

Cross Multiply

### Buoyancy

• The force that acts on objects immersed in or floating on a liquid

Photo from: http://www.seed.slb.com/en/scictr/watch/bathroom/duck.htm

### Buoyancy

• Buoyancy is related to floating

• an object in a liquid is buoyed up (pushed up) by a force equal to the weight of the liquid the object displaces (pushes aside). This is known as Archimedes’ Principle.

Photo from: http://www.seed.slb.com/en/scictr/watch/bathroom/duck.htm

### Viscosity

• Viscosity is the resistance of a liquid to flow

• If a liquid flows slow, it is viscous, or has a high viscosity

The Great Salt Lake

• The Great Salt Lake is a large inland lake. It is very unusual because it is made up of saltwater. In 1959 a railroad causeway was built across the lake. The causeway, made from rocks and cement, divides the lake into two bays, Gilbert Bay and Gunnison Bay. Although the material in the causeway is tightly packed, the causeway is porous, allowing for the exchange of water between the two bays. Over time, as fresh surface water flows into the Great Salt Lake, the depth of each bay and the composition of the water can vary. More freshwater flows into Gilbert Bay than into Gunnison Bay. Therefore, the water in Gunnison Bay is saltier than the water in Gilbert Bay. When the difference in salt composition is great, some of the saltier water from Gunnison Bay flows into Gilbert Bay through the causeway. Some properties of both bays were measured in 1998 and are shown in the table below.

From the data in the table, what would be the mass of a 3.0 L sample of water collected from Gunnison Bay?

A 2515 g

B 3171 g

C 3579 g

D 4193 g

What is the density at 20°C of 12.0 milliliters of a liquid that has a mass of 4.05 grams?

A 0.338 g/mL

B 2.96 g/mL

C 16.1 g/mL

D 48.6 g/mL

Powerful Plankton

The U.S. Naval Research Laboratory has created an experimental marine fuel cell that could produce enough electricity to power ocean-monitoring devices. This fuel cell runs on seawater and sediment, with the help of plankton. Some plankton on the surface of ocean sediments use dissolved oxygen to break down organic matter, releasing energy; this is an aerobic process. The plankton in the deeper sediments break down organic matter without using oxygen; this is an anaerobic process. These two processes create a difference in voltage between the surface of the sediment and the sediment farther down in the seabed. The voltage difference can be used to produce electricity-up to 5.0 x 10 – 2 watts of power. Energy supplied by this type of fuel cell can be obtained as long as there is organic matter in the sediment.

What is the mass of a 500.00 mL sample of seawater with a density of 1.025 g/mL?

F 487.8 g

G 500.0 g

H 512.5 g

J 625.0 g

## IPC 7E – Classify samples of matter from everyday life as being elements, compounds, or mixtures.

### 2 Classes of Matter

• Mixtures

• Pure Substances

• Elements

• Compounds

### 2 TYPES OF MIXTURES

• Heterogeneous

• Homogeneous

Heterogeneous Mixture

### mixture made up of TWO OR MORE distinct phases with different properties (not uniform throughout)

contains a liquid in which visible particles settle

scatter light

can be separated using filter paper

### Examples of Homogeneous Mixtures

Also: Salt Water, Sugar Water

and most clean air

!

• Solute

• Solvent

Solvent

Solute

=

### Supersaturated Solutioncontains more solute than it should theoretically be able to hold at a certain temp

Salt is added to a beaker of water and stirred until it is completely dissolved. The salt in this mixture can be separated by —

A chromatography

B chemical means only

C passing the water through filter paper

D allowing the water to evaporate slowly

The picture shows a model of the element —

A fluorine

B helium

C beryllium

D oxygen

The first equation represents photosynthesis. Plants use energy from sunlight to produce sugar and oxygen from carbon dioxide and water. The second equation represents aerobic respiration. Plants and animals release stored energy in a reaction between sugar molecules and oxygen. This reaction produces carbon dioxide and water.

Oxygen (O2) is an example of —

A an alloy

B a molecule

C a salt

D a mixture

An unknown silvery powder has a constant melting point and does not chemically or physically separate into other substances. The unknown substance can be classified as —

A an element

B a compound

C a mixture

D an alloy

IPC 8A – Distinguish between physical and chemical changes in matter such as oxidation, digestion, changes in state, and stages of the rock cycle.

### Physical Changes

More Examples

• Cutting

• Breaking apart

All of these represent a change in state of

matter except —

A melting an ice block

B evaporating alcohol

C sublimating dry ice

D digesting a sugar cube

In the rock cycle, which of these is a chemical change involved with the formation of igneous rocks? F Compression of sediments

G Heat loss from lava

H Subduction of plates

J Formation of minerals

Which of the following is an example of a chemical change?

F Ice cracking

G Sugar dissolving

H Milk souring

What characteristic of water remains the same no matter what is dissolved in it ?

A The ratio of hydrogen to oxygen

B The ability to refract light

C The hydroxide ion concentration

D The freezing temperature

Which of these describes a pollution-producing process that involves only a physical change?

A Coal with a high sulfur content is burned, producing gases that cause acid rain.

B Chlorofluorocarbons are released, changing ozone in the upper atmosphere into oxygen.

C Hot wastewater is discharged into a lake, lowering oxygen levels in the water.

D Nitrogen oxide emissions combine with water vapor, producing nitric acid.

## Law of Conservation of Mass

Mass can not be created or destroyed

2H2 + O2 2H2O

H2O(s)  H2O(l)

C + O2  CO2

100 grams

50 grams

?

150 grams

32 grams

32 grams

20 grams

?

60 grams

40 grams

## Balancing Equations

A reaction must be balanced to obey the law of conservation of mass

• Non-balanced Reaction

H2 + O2 H2O

• Balanced Reaction

2H2 + O2 2H2O

### How to balance a reaction

• Step one: list all the element symbols under the arrow of a reaction

H2 + O2 H2O

H

O

### How to balance a reaction

• Step two: count how many of each atom you have on each side of the reaction

H2 + O2 H2O

2

H

2

2

1

O

### Coefficients

• Numbers that are placed in front of a compound/molecules in a reaction

### How to balance a reaction

• Step three: add coefficients to the compounds to help make each element even on both sides

H2 + O2 H2O

2

2

4

4

2

H

2

2

2

1

O

2

2

H2 + O2 H2O

### Balance Me!

2

4

2

2

2

___ XeF2 + ___ H2O  __ Xe + __ O2 + __ HF

2

2

1

Xe

1

4

2

4

2

F

1

4

2

4

2

H

1

2

1

2

O

If 43.7 g of iron is completely used in the reaction above, how many grams of oxygen are involved in the reaction? Record and bubble in your answer to the nearest tenth on the answer document.

18.8g

The first equation represents photosynthesis. Plants use energy from sunlight to produce sugar and oxygen from carbon dioxide and water. The second equation represents aerobic respiration. Plants and animals release stored energy in a reaction between sugar molecules and oxygen. This reaction produces carbon dioxide and water.

To produce 4 molecules of sugar, a plant needs —

F 6 molecules of hydrogen

G 12 molecules of ATP

H 18 molecules of water

J 24 molecules of carbon dioxide

What are the coefficients that will balance this chemical equation?

A 2, 1, 1

B 3, 4, 2

C 2, 2, 1

D 4, 3, 2

The illustrations show a conservation-of-mass experiment. The solution in the beaker lost mass because —

F materials have less mass at high temperatures

G the mass of the reactants and products was less than 100g

H sodium sulfate (Na2SO4) is lighter than air

J some of the water molecules turned into gas

## IPC 9A – Relate the structure of water to its function [as the universal solvent].

### The water molecule: formula

1. What is the chemical formula for water?

H2O

2. How many types of atoms in a water molecule?

2 (hydrogen

and oxygen)

3. What is the total number of atoms in a water molecule?

3 (2 hydrogen and 1 oxygen)

### The Water Molecule: Polarity

1. Polar refers to unequal sharing of electrons.

Polarity creates partial positive charges and partial negative charges.

2. How many protons does an oxygen atom have in its nucleus?

8

The charge of the nucleus of an oxygen atom is +8.

3. How many protons does a hydrogen atom have in its nucleus?

1

The charge of the nucleus of a hydrogen atom is +1.

In a water molecule, are the electrons more likely to be near the oxygen nucleus or the hydrogen nucleus?

Oxygen nucleus

(-)

O

(+)

(+)

H

(-)

H

(-)

O

O

(+)

H

(+)

H

(+)

(+)

H

(-)

H

(-)

O

(-)

O

O

H

H

(+)

H

(+)

H

(+)

H

H

(+)

(+)

(+)

### Hydrogen bonding

Why are the charges in parentheses?

they are partial charges

Which factor makes water an effective solvent?

F The presence of molecular oxygen

G Its lack of covalent bonds

H The polar nature of its molecules

J Its abundance on Earth’s surface

## IPC 9D – Demonstrate how various factors influence solubility including temperature, pressure, and nature of the solute and solvent.

• More solute will result in a boiling point elevation (increase) and freezing point depression (decrease)

• Why do people put salt on icy roads?

The Great Salt Lake

• The Great Salt Lake is a large inland lake. It is very unusual because it is made up of saltwater. In 1959 a railroad causeway was built across the lake. The causeway, made from rocks and cement, divides the lake into two bays, Gilbert Bay and Gunnison Bay. Although the material in the causeway is tightly packed, the causeway is porous, allowing for the exchange of water between the two bays. Over time, as fresh surface water flows into the Great Salt Lake, the depth of each bay and the composition of the water can vary. More freshwater flows into Gilbert Bay than into Gunnison Bay. Therefore, the water in Gunnison Bay is saltier than the water in Gilbert Bay. When the difference in salt composition is great, some of the saltier water from Gunnison Bay flows into Gilbert Bay through the causeway. Some properties of both bays were measured in 1998 and are shown in the table below.

After studying salinity in the bays of the Great Salt Lake, students prepared two samples of water having different salinity. Sample A contained 10% salt, and Sample B contained 25% salt. Both samples were the same size. After leaving the samples in the freezer for the same amount of time, the students discovered that a layer of ice had formed in each sample. Which layer in the samples probably contained the most salt?

A The ice layer in Sample A

B The liquid layer in Sample A

C The ice layer in Sample B

D The liquid layer in Sample B

Which of the following salts has the greatest solubility in water at 25°C?

F CaCO3

G FeS

H HgCl2

J KClO4

As a scuba diver goes deeper underwater, the diver must be aware that the increased pressure affects the human body by increasing the —

A body’s temperature

B amount of dissolved gases in the body

C amount of suspended solids in the body

D concentration of minerals in the body