# Objective 4: Structures and Properties of Matter

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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 The force that acts on objects immersed in or floating on a liquid Photo from:

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:

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
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
What is the density at 20°C of 12.0 milliliters of a liquid that has a mass of 4.05 grams? A 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 mL sample of seawater with a density of g/mL? F g G g H g J g

Which of the following objects will float on water?

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

2 Classes of Matter Mixtures Pure Substances

Pure Substances Elements Compounds

MIXTURE matter that contains 2 or more materials that can be physically separated (ex. cheeseburger & Lucky Charms)

2 TYPES OF MIXTURES Heterogeneous Homogeneous

Heterogeneous Mixture Examples: salad, vegetable soup, concrete
mixture made up of TWO OR MORE distinct phases with different properties (not uniform throughout) Examples: salad, vegetable soup, concrete

SUSPENSION contains a liquid in which visible particles settle
scatter light can be separated using filter paper Ex: Italian salad dressing

COLLOID particles are mixed together, but not dissolved; scatter light; will not separate upon standing; appear cloudy; ex: shaving cream

Homogeneous Mixture mixture made up of ONLY 1 phase (uniform throughout)

Examples of Homogeneous Mixtures
Also: Salt Water, Sugar Water and most clean air

Homogeneous Mixtures are also known as SOLUTIONS!

Solutions are made up of two parts
Solute Solvent

SOLUTE the part of a solution that is dissolved

SOLVENT the part of a solution that does the dissolving

Solvent Solute = SOLUTION!!!

Solubility amount of solute that will dissolve in an amount of solvent at a given temperature

Saturated Solution contains the maximum amount of solute for an amount of solvent at a given temperature

Unsaturated Solution contains less solute than a saturated solution

Supersaturated Solution contains 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
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 J Lead melting

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.

IPC 8C – Investigate and identify the law of conservation of mass.

Law of Conservation of Mass
Mass can not be created or destroyed

Using the Law of Conservation of mass
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 H O2  H2O 2 2 4 4 2 H 2 2 2 1 O

The reaction 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
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?
D 4, 3, 2

The illustrations show a conservation-of-mass experiment
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. Look at your periodic table: 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

Hydrogen bonding Why are the charges in parentheses?
they are partial charges H O (-) (+)

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
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

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