AMU CHEM 134 STUDY GUIDE
Identify each of the following statements as being most similar to a hypothesis, a law, or a theory. Explain your reasoning. (a) The pressure of a sample of gas is directly proportional to the temperature of the gas. (b) Matter consists of tiny particles that can combine in specific ratios to form substances with specific properties. (c) At a higher temperature, solids (such as salt or sugar) will dissolve better in water.
(a) law (states a consistently observed phenomenon, can be used for prediction) (b) theory (a widely accepted explanation of the behavior of matter) (c) hypothesis (a tentative explanation, can be investigated by experimentation)
Identify each of the underlined items as a part of either the macroscopic domain, the microscopic domain, or the symbolic domain of chemistry. For those in the symbolic domain, indicate whether they are symbols for a macroscopic or a microscopic feature. (a) A certain molecule contains one H atom and one Cl atom. (b) Copper wire has a density of about 8 g/cm3. (c) The bottle contains 15 grams of Ni powder. (d) A sulfur molecule is composed of eight sulfur atoms.
(a) symbolic, microscopic (b) macroscopic (c) symbolic, macroscopic (d) microscopic
each hazard is rated on a scale from
0 to 4, with 0 being no hazard and 4 being extremely hazardous.
Example: Convert the volume 3.5 ft^3 to cm^3.
1 inch = 2.54 cm 12 inches = 1 foot 9.9x10^4 cm^3
Indicate the SI base units or derived units that are appropriate for the following measurements: 1.) the mass of the moon 2.) the distance from Dallas to Oklahoma City 3.) the speed of sound 4.)the density of air 5.)the temperature at which alcohol boils 6.)the area of the state of Delaware 7.)the volume of a flu shot or a measles vaccination
1) kilograms 2) meters 3)kilometers/second 4) kilograms/cubic meter 5) kelvin 6) square meters 7) cubic meters
Many of the items you purchase are mixtures of pure compounds. Select three of these commercial products and prepare a list of the ingredients that are pure compounds.
1.) Gatorade contains a mixture of pure compounds such as dextrose, sugar, citric acid. salt, monopotassium phosphate and sucrose acetate isobutyrate. 2.) SmartWater is a mixture of pure compounds such as calcium chloride, magnesium chloride, water and potassium bicarbonate. 3.) Mountain dew contains a mixture of pure compounds such as carbonated water, sugar, sodium benzoate, caffeine, orange juice, citric acid, sodium citrate, gum arabic and erythorbic acid.
Indicate the SI base units or derived units that are appropriate for the following measurements: 1.) the length of a marathon race (26 miles 385 yards) 2.)the mass of an automobile 3.)the volume of a swimming pool 4.)the speed of an airplane 5.)the density of gold 6.)the area of a football field 7.)the maximum temperature at the South Pole on April 1, 1913
1.) The SI unit for distance - meter 2.) The SI unit for mass-kilogram 3.) The SI unit for volume- M^3 4.)the unit for speed is m/s 5.) the SI unit for density - kg/m^3 6.) the SI unit of area - m^2 7.) SI unit temperature - Kelvin or K
Classify each of the following as an element, a compound, or a mixture: 1.) iron 2.) oxygen 3.) mercury oxide 4.) pancake syrup 5.) carbon dioxide 6.) a substance composed of molecules each of which contains one 7.) hydrogen atom and one chlorine atom 8.) baking soda 9.) baking powder
1.) element 2.)element 3.)compound 4.) mixture 5.) compound 6.) compound 7.)compound 8.))compound 9.) mixture
Classify each of the following as an element, a compound, or a mixture: 1.)copper 2.)water 3.)nitrogen 4.)sulfur 5.)air 6.)sucrose 7.)a substance composed of molecules each of which contains two iodine atoms 8.) gasoline
1.)element 2.)compound 3.)element 4.)element 5.)mixture 6.)compound 7.)element 8.)mixture
A sample of mercury with a mass of 114.0 g was combined with 12.8 g of oxygen gas and the resulting reaction gave 123.1g of mercury (II) oxide. How much oxygen was left over after the reaction is complete?
123.1g-114.0g = 9.1g of O
A 2.0-liter volume of hydrogen gas combined with 1.0 liter of oxygen gas to produce 2.0 liters of water vapor. Does oxygen undergo a chemical or physical change?
A Chemical change is when matter combines to form new substances. In this problem, oxygen reacts with hydrogen to form a new substance (water) so oxygen undergoes a chemical change.
Classify each of the following changes as physical or chemical: (a) condensation of steam (b) burning of gasoline (c) souring of milk (d) dissolving of sugar in water (e) melting of gold
A change that does not bring any difference in chemical composition of a substance are known as physical changes. For example, dissolving sugar in water, melting of gold, condensation of steam etc are all physical changes. Whereas a change which causes difference in chemical composition of a substance is known as chemical change. For example, souring of milk, burning of gasoline etc are chemical changes. a. physical b. chemical c. chemical d. physical e. physical
Classify each of the following changes as physical or chemical: coal burning ice melting mixing chocolate syrup with milk explosion of a firecracker magnetizing of a screwdriver
A physical change changes the physical form or the appearance or the property of the substance, but the chemical composition of the matter remains the same. Such a change is reversible in nature (a) coal burning: It is a chemical change because the combustion of coal changes its chemical composition. When coal (carbon) is burned carbon dioxide is released. Irreversible in nature (b)ice melting: It is a physical change because ice the solid phase of water melts to get converted to the liquid phase of water only and no change in the chemical composition is seen. (c) mixing chocolate syrup with milk : It is a physical change because on dissolving chocolate syrup in milk, only the color of the milk changes, therefore there is change in the property. As, it involves mixing of two miscible liquids and does not involve any change in the chemical composition of either of the two liquids. (d) explosion of a firecracker: it is a chemical process, as it involves combustion of an explosive material to produce carbon dioxide, carbon monoxide and water vapour. It is a chemical change because it involves change in the chemical composition. Irreversible in nature (e) magnetizing of a screwdriver: It is physical change because on magnetization only the magnetic property of the screwdriver changes AND there is no change in the chemical composition of the matter.
When elemental iron corrodes it combines with oxygen in the air to ultimately form red brown iron(III) oxide which we call rust. A.) If a shiny iron nail with an initial mass of 23.2 g is weighed after being coated in a layer of rust, would you expect the mass to have increased, decreased, or remained the same? B.) If the mass of the iron nail increases to 24.1 g, what mass of oxygen combined with the iron?
A.) As iron rod contain only iron molecules, hence, the mass of the iron rod increases after being coated in a layer of rust. B.)24.1G-23.2G= 0.9G OXYGEN
As stated in the text, convincing examples that demonstrate the law of conservation of matter outside of the laboratory are few and far between. Indicate whether the mass would increase, decrease, or stay the same for the following scenarios where chemical reactions take place: A.) Exactly one pound of bread dough is placed in a baking tin. The dough is cooked in an oven at 350 °F releasing a wonderful aroma of freshly baked bread during the cooking process. Is the mass of the baked loaf less than, greater than, or the same as the one pound of original dough? Explain. B.) When magnesium burns in air a white flaky ash of magnesium oxide is produced. Is the mass of magnesium oxide less than, greater than, or the same as the original piece of magnesium? C.) Antoine Lavoisier, the French scientist credited with first stating the law of conservation of matter, heated a mixture of tin and air in a sealed flask to produce tin oxide. Did the mass of the sealed flask and contents decrease, increase, or remain the same after the heating?
A.) Less Than The mass of the baked loaf will be less than the original dough. In making dough for bread, we have ingredients that are liquid such as water, melted butter, food flavoring, etc. All of this liquid ingredients mixed on the dough will definitely turn into vapor. This vapor is responsible for releasing of the aroma of the freshly baked bread. B.) Greater than The mass of the magnesium oxide product would be greater than the original magnesium metal as the amount of magnesium remains the same, but having combined with oxygen, the total matter increases. C.) The mass of the sealed flask and contents would remain the same as no reactants or products leave the flask, and therefore the quantity of matter in the flask does not change.
Why do scientist rely on mass rather than weight as the measurement of how much matter an object contains?
Because unlike its weight, an objects mass will not change if the force of gravity changes.
Which of the following is not a chemical change? A. burning coal B. making bread rise using baking soda C. boiling an egg D. boiling water
Boiling water is not a chemical change it is a physical change.
John Dalton (1766-1844)
British schoolteacher with a keen interest in science, supported this hypothesis with quantitative measurements
Explain the difference between extensive properties and intensive properties
Extensive properties, such as mass and volume, depend on the amount of matter being measured. Intensive properties, such as density and color, do not depend on the amount of the substance present. Physical properties can be measured without changing a substance's chemical identity.
As we drive an automobile, we don't think about the chemicals consumed and produced. Prepare a list of the principal chemicals consumed and produced during the operation of an automobile.
Gasoline (a mixture of compounds), oxygen, and to a lesser extent, nitrogen are consumed. Carbon dioxide and water are the principal products. Carbon monoxide and nitrogen oxides are produced in lesser amounts.
How are the molecules in oxygen gas, the molecules in hydrogen gas, and water molecules similar? How do they differ?
Hydrogen gas is two hydrogen atoms bonded together, H2. Oxygen gas is two oxygen atoms bonded together, O2. Water, is one oxygen atom bonded to two different hydrogen atoms, H2O
extensive property
If the property depends on the amount of matter present i.e. mass and volume
intensive property
If the property of a sample of matter does not depend on the amount of matter present i.e. temperature
A sulfur atom and a sulfur molecule are not identical. What is the difference?
In each case, a molecule consists of two or more combined atoms. They differ in that the types
What properties distinguish solids from liquids? Liquids from gases? Solids from gases?
Liquids can change their shape (flow); solids can't. Gases can undergo large volume changes as pressure changes; liquids do not. Gases flow and change volume; solids do not.
How does an atom differ from a molecule? In what ways are they similar?
Molecules are groups of two or more atoms held together by chemical bonds.
How do molecules of elements and molecules of compounds differ? In what ways are they similar?
Molecules of elements contain only one type of atom; molecules of compounds contain two or more types of atoms. They are similar in that both are comprised of two or more atoms chemically bonded together.
How does an element differ from a compound? How are they similar?
Molecules of elements contain only one type of atom; molecules of compounds contain two or more types of atoms. They are similar in that both are comprised of two or more atoms chemically bonded together.
Explain how you could experimentally determine whether the outside temperature is higher or lower than 0 °C (32 °F) without using a thermometer?
Place a glass of water outside. It will freeze if the temperature is below 0 °C.
We usually report the results of scientific measurements in
SI units
Matter is everywhere around us. Make a list by name of fifteen different kinds of matter that you encounter every day. Your list should include (and label at least one example of each) the following: a solid, a liquid, a gas, an element, a compound, a homogenous mixture, a heterogeneous mixture, and a pure substance.
SOLID: Stone, Sand, gravel LIQUID: Water, diesel, ethanol GAS: Oxygen, Carbon dioxide ELEMENT: Copper, Iron, Silver COMPOUND: Sodium chloride (NaCl) Hydrogen Chloride (HCl) HOMOGENEOUS MIXTURE: Air, Blood HETEROGENEOUS MIXTURE: Orange juice, Oily water PURE SUBSTANCE: Aluminum, Gold
chemical property
The change of one type of matter into another type (or the inability to change)
We use the mass and volume of a substance to determine its density. Thus, the units of density are defined by the base units of mass and length.
The density of a substance is the ratio of the mass of a sample of the substance to its volume. The SI unit for density is the kilogram per cubic meter (kg/m3)
We refer to astronauts in space as weightless, but not without mass. Why?
The force of gravity is very small in space. The lack of attention between bodies and the astronauts weight is essentially absent. However, they do keep their intrinsic mass.
The density (d) of a substance is an intensive property that is defined as the ratio of its mass (m) to its volume (v). density= mass/volume d=m/V Considering that mass and volume are both extensive properties, explain why their ratio, density, is intensive.
The intensive properties don´t depend on mass or size, if you have a liter of water, this litter have a density equal 1000 kg/m^3. If you have 250 liters of water, the density is 1000 kg/m^3 too. The density does not change with the addition or substraction of matter.
How does a heterogeneous mixture differ from a homogeneous mixture? How are they similar?
The mixture can have a variety of compositions; a pure substance has a definite composition. Both have the same composition from point to point.
How does a homogeneous mixture differ from a pure substance? How are they similar?
The mixture can have a variety of compositions; a pure substance has a definite composition. Both have the same composition from point to point.
Volume is the measure of the amount of space occupied by an object
The standard volume is a cubic meter (m3), a cube with an edge length of exactly one meter.
The amount of heat required to melt 2 lbs of ice is twice the amount of heat required to melt 1 lb of ice. Is this observation a macroscopic or microscopic description of chemical behavior? Explain your answer.
This is a macroscopic observation. Explanation: When you have something that It is depends on the mass, you can be sure that this is a macroscopic description of chemical behavior, because macroscopic observation can be measured with extensive magnitudes such as volume, mass, and length.
According to one theory, the pressure of a gas increases as its volume decreases because the molecules in the gas have to move a shorter distance to hit the walls of the container. Does this theory follow a macroscopic or microscopic description of chemical behavior? Explain your answer.
This theory follows microscopic description molecules in the gas are determined on microscopic properties
Identify the following properties as either extensive or intensive. volume temperature humidity heat boiling point
When amount of matter changes in a substance then a physical property that does not change due to this is known as an intensive property. For example, density, color, boiling point, hardness etc are all intensive properties. Whereas property of a substance that changes due to change in amount of matter of a substance is known as extensive property. For example, temperature, volume etc are all extensive properties. Hence, we can conclude that given properties are classifies as follows. Intensive property : color, hardness, boiling point, density, temperature. Extensive property : length, volume, mass.
physical change
a change in the state or properties of matter without any accompanying change in its chemical composition
physical property
a characteristic of matter that is not associated with a change in its chemical composition.
mass
a measure of the amount of matter in it
Is one liter about an ounce, a pint, a quart, or a gallon?
a quart 1 gallon is equal to 3.78541 liters. 1 pint is equal to 0.473176 liters. 1 ounce is equal to 0.0295735 liters. 1 quart is equal to 0.94635 liters.
Identify each of the underlined items as a part of either the macroscopic domain, the microscopic domain, or the symbolic domain of chemistry. For those in the symbolic domain, indicate whether they are symbols for a macroscopic or a microscopic feature. a.) The mass of a lead pipe is 14 lb. b.)The mass of a certain chlorine atom is 35 amu. c.)A bottle with a label that reads Al contains aluminum metal. d.) Al is the symbol for an aluminum atom.
a.) macroscopic b.) microscopic c.) Symbolic; microscopic d.) Symbolic; microscopic
Label the following as intensive or extensive properties: a) volume b) temperature c) odor d) melting point e) color
a.)extensive (qty) b.)intensive c.)intensive (doesn't change) d.)intensive (melt at the same point doesn't change) e.)intensive (doesn't change)
Is a meter about an inch, a foot, a yard, or a mile?
about a yard
A chemical change always
always produces one or more types of matter that differ from the matter present before the change.
Water freezes at 273.15 K (0 °C) and boils at 373.15 K (100 °C)
and normal human body temperature is approximately 310 K (37 °C)
chemical property
behavior that is related to the change of one kind of matter into another kind of matter
shorter distances can be reported in
centimeters (1 cm = 0.01 m = 10−2 m) or millimeters (1 mm = 0.001 m = 10−3 m)
physical change
change in the state or properties of matter that does not involve a change in its chemical composition
chemical change
change producing a different kind of matter from the original kind of matter
Pure substances that can be broken down by chemical changes are called
compounds
Matter
defined as anything that occupies space and has mass
YELLOW "hazard diamond"
describes reactivity hazards, such as how readily the substance will undergo detonation or a violent chemical change.
Pure substances that cannot be broken down into simpler substances by chemical changes are called
elements
We can divide pure substances into two classes:
elements and compounds
A homogeneous mixture, also called a solution
exhibits a uniform composition and appears visually the same throughout i.e. sports drinks
liquid
flows and takes the shape of a container, except that it forms a flat or slightly curved upper surface when acted upon by gravity.
Weight refers to the
force that gravity exerts on an object
fourth state of matter plasma
gaseous state of matter that contains appreciable numbers of electrically charged particles
pure substance
has a constant composition
A mixture with a composition that varies from point to point is called a
heterogeneous mixture i.e. cookies or salad dressing
Yeast converts glucose to ethanol and carbon dioxide during anaerobic fermentation as depicted in the simple chemical equation here: A.)If 200.0g of glucose is fully converted, what will be the total mass of ethanol and carbon dioxide produced? B.) If the fermentation is carried out in an open container, would you expect the mass of the container and contents after fermentation to be less than, greater than, or the same as the mass of the container and contents before fermentation? C.) If 97.7 g of carbon dioxide is produced, what mass of ethanol is produced?
https://www.nagwa.com/en/videos/659180404237/ A.) 200.0G (REMAINS THE SAME) B.) DECREASE C.)200.G-92.7G=102.3G OF CARBON DIOXIDE
BLUE "hazard diamond"
indicates the level of health hazard
Temperature is an intensive property. The SI unit of temperature is the
kelvin (K)
The standard unit of mass in the SI system is the
kilogram (kg) defined by a certain cylinder of platinum-iridium alloy, which is kept in France. Any object with the same mass as this cylinder is said to have a mass of 1 kilogram. One kilogram is about 2.2 pounds
Longer distances are often reported in
kilometers (1 km = 1000 m = 103 m)
The weight of an object changes as the force of gravity changes, but its (____) does not
mass
One way to measure an object's mass is to
measure the force it takes to accelerate the object.
The standard unit of length in both the SI and original metric systems is the
meter (m) A meter is about 3 inches longer than a yard one meter is about 39.37 inches or 1.094 yards
scientific method
path of discovery that leads from question and observation to law or hypothesis to theory, combined with experimental verification of the hypothesis and any necessary modification of the theory
Classify the six underlined properties in the following paragraph as chemical or physical: Fluorine is a pale yellow gas that reacts with most substances. The free element melts at −220 °C and boils at −188 °C. Finely divided metals burn in fluorine with a bright flame. Nineteen grams of fluorine will react with 1.0 gram of hydrogen.
physical chemical physical physical chemical chemical
The volume of a sample of oxygen gas changed from 10 mL to 11 mL as the temperature changed. Is this a chemical or physical change?
physical change In this case, the volume of a sample of oxygen gas changed from 10 ml to 11 ml as the temperature changed. This is a physical change because the oxygen sample is the same before and after the change and its properties do not change. In summary, this is a physical change
WHITE "hazard diamond"
points out special hazards, such as if it is an oxidize
extensive property
property of a substance that depends on the amount of the substance
intensive property
property of a substance that is independent of the amount of the substance
macroscopic domain
realm of everyday things that are large enough to sense directly by human sight and touch
microscopic domain
realm of things that are much too small to be sensed directly
solid
rigid and possesses a definite shape
The SI base unit of time is the
second (s)
symbolic domain
specialized language used to represent components of the macroscopic and microscopic domains, such as chemical symbols, chemical formulas, chemical equations, graphs, drawings, and calculations
RED "hazard diamond"
specifies the level of fire hazard (temperature range for flash point)
law
statement that summarizes a vast number of experimental observations, and describes or predicts some aspect of the natural world
The law of conservation of matter
states that there is no detectable change in the total quantity of matter present when matter converts from one type to another (a chemical change) or changes among solid, liquid, or gaseous states (a physical change)
chemistry
study of the composition, properties, and interactions of matter
Matter can also have properties of more than one state when it is a mixture
such as with clouds
gas
takes both the shape and volume of its container.
hypothesis
tentative explanation of observations that acts as a guide for gathering and checking information
Every measurement provides three kinds of information:
the size or magnitude of the measurement (a number); a standard of comparison for the measurement (a unit); and an indication of the uncertainty of the measurement.
atom
the smallest particle of an element that has the properties of that element and can enter into a chemical combination
The standards for these units are fixed by international agreement
they are called the International System of Units or SI Units
"fire diamond" or "hazard diamond"
this chemical hazard diamond provides valuable information that briefly summarizes the various dangers of which to be aware when working with a particular substance.
molecule
two or more atoms joined by strong forces called chemical bonds
A mixture is composed of
two or more types of matter that can be present in varying amounts and can be separated by physical changes, such as evaporation
Theory
well-substantiated, comprehensive, testable explanation of a particular aspect of nature
The degree Celsius (°C) is also allowed in the SI system
with both the word "degree" and the degree symbol used for Celsius measurements. Celsius degrees are the same magnitude as those of kelvin, but the two scales place their zeros in different places.
