True or False: Many substances (e.g. water) exist in all 3 phases, depending on temperature.
Out of the Three States of Matter, describe the properties and characteristics of a solid.
Fixed shape and volume, does not conform to the shape or volume of the container.
Describe a crystalline solid.
The constituent particles (molecules or atoms) repeat in a regular fashion in all three dimensions.
NaCl is an example of this.
Describe an amorphous solid.
The constituent particles (molecules or atoms) do not repeat in a regular fashion.
Glass is an example of this.
Is a solid compressible or incompressible? Why?
Incompressible because particles are in direct contact with each other (just like liquids).
More most substances, density of the substance as a solid is _______ than that of either the liquid or the gas forms. What is at least one important exception?
Out of the Three States of Matter, describe the properties and characteristics of a liquid.
Liquids do not have a fixed shape but do have a fixed volume.
Liquids are like _______ solids in structure.
Is a liquid compressible or incompressible? Why?
Incompressible because particles are in direct contact with each other (just like solids).
For most liquid substances, density is slightly _______ than that of a solid. What kind of liquid is an exception?
Out of the Three States of Matter, describe the properties and characteristics of a gas.
Does not have either a fixed shape nor a fixed volume.
Is a gas compressible or incompressible? Why?
Compressible because there are large spaces between molecules (unlike liquids and solids).
For all gaseous substances, density is much _______ than that of corresponding liquids or solids. Why?
lower; most of a gas sample is empty space.
For any given substance, the solid and liquid have _______ densities, while that of the gas has a much _______ density.
What are three different compositions that classify matter?
Elements, compounds, and mixtures.
What is an element?
A substance that is composed of only one kind of atom.
What is a compound?
A substance that is composed of two or more kinds of atoms (elements) in fixed proportions by mass, unlike mixtures.
A compound is formed when two or more elements are bonded together and form a new substance.
What are some examples of a compound?
H2O (11.2% H, 88.8% O)
H2O2 (5.9% H, 94.1% O)
FeCl2 (44.1% Fe, 55.9% Cl)
FeCl3 (34.4% Fe, 65.6% Cl)
Another definition of a compound is: A substance consisting of atoms of two or more _______ in which the ratio of atoms of one _______ to that of each of the others is _______. This is reflected in the formula for the compound.
element; element; fixed
What is a mixture?
A combination of two or more substances in which each substance retains its identity. Its composition is not constant.
A mixture is formed when two or more pure substances are mixed together; however, a new substance is not formed.
What is a homogeneous mixture? What are some examples?
A mixture in which the composition is the same in each part of the mixture.
Examples: air, salt water.
What is a heterogeneous mixture? What are some examples?
A mixture in which the individual components remain physically separate i.e. the composition may change drastically from one small sample to the next.
An example of this is a chocolate chip cookie: not every bite yields the same amount of chocolate chips.
In a chemical mixture, does separating the substances yield a changing of the identity of any of the components?
No. In a mixture, all substances involved retain their identity.
Is air an element, compound, homogeneous mixture or a heterogeneous mixture?
Is sugar an element, compound, homogeneous mixture or a heterogeneous mixture?
Is tea an element, compound, homogeneous mixture or a heterogeneous mixture?
Is copper an element, compound, homogeneous mixture or a heterogeneous mixture?
Is rust an element, compound, homogeneous mixture or a heterogeneous mixture?
Is N2 gas an element, compound, homogeneous mixture or a heterogeneous mixture?
Is the human body an element, compound, homogeneous mixture or a heterogeneous mixture?
Is chicken noodle soup an element, compound, homogeneous mixture or a heterogeneous mixture?
How do we tell matter apart?
By physical and chemical properties.
What is a physical property?
Can be observed without changing the identity or composition of a substance, although the physical form changes.
What is a physical change?
No change in composition or identity but physical form is changed.
What is a chemical property?
Can be observed only when the composition or identity of the sample is changed.
What is a chemical change?
Chemical change = chemical reaction. There is a change in the identity or composition of the substance or substances present.
Wood floats. This is an example of which kind of property?
Wood burns. This is an example of which kind of property?
Iron can be bent. This is an example of which kind of property?
Iron rusts. This is an example of which kind of property?
What is an example of separating mixtures through physical changes?
Separating sand from water.
Separating a mixture such as sand and water by allowing the sand to settle and then pouring off the water from the top.
Separating a mixture such as sand and water by pouring the mixture into a funnel containing filter paper. The water passes through the filter paper but the pores are too small for the sand to pass through.
Separating a mixture such as sand and water by heating the mixture to a boil. The water, which is volatile (easily vaporized) boils off, leaving the sand behind.
Describe the Law of Conservation of Mass.
There is no new matter, cannot be created, nor destroyed.
Using NH4N3, give an example of the law of conservation of mass.
NH4N3 ---> 2 N2 + 2 H2
60g of NH4N3 gives exactly 56g of N2 and _______g of H2 and no other products.
What is energy?
The capacity to do work.
What is the Law of Conservation of Energy?
Energy can be neither created nor destroyed. However, one form of energy can be converted into another form of energy.
What is kinetic energy?
Energy of motion
What is potential energy?
Energy of position (example: object right before it is dropped).
What is electrical energy?
energy associated with the flow of electricity.
What is chemical energy?
A form of potential energy that can be released during chemical reactions.
Example: flashlight battery
What is an exothermic process? Give an example.
A process that gives off energy.
Example: burning wood. The temperature tends to rise during the process; heat is released.
What is an endothermic process? Give an example.
A process that absorbs energy.
Example: evaporation of a liquid, ice/cold packs. The temperature tends to drop during the process, heat is absorbed.
True or False: All forms of energy can have the same units but customarily do not.
What is the definition of a calorie?
Amount of energy needed to raise the temperature of exactly 1 gram of H2O by exactly 1oC
What is the SI unit of energy? How many of these units equates to 1 calorie?
joule (symbol: J)
1 calorie = 4.184 joules
Besides the calorie, what are other energy units?
1 Calorie = 1,000 calories = 1 kilocalorie
1 kilowatt-hour = 3,600,000 joules
What is temperature?
Random molecular and atomic motion.
What causes a higher temperature?
The faster the molecules or atoms are moving, the higher the temperature T.
In oF, what is the freezing point and boiling point of water (at sea level)?
Freezing = 32oF
Boiling = 212OF
In oC, what is the freezing point and boiling point of water (at sea level)?
Freezing = 0oC
Boiling = 100oC
What is the difference between the freezing points and boiling points of both oF and oC distinctly?
oF = 180oF (212oF - 32oF)
oC = 100oC (100oC - 0oC)
What is the equation to convert oF into oC?
oC = (5/9)(oF - 32)
What is the equation to convert oC into oF?
oF = (9/5)oC + 32
Setup the equation to convert 68oF into oC.
oC = (5/9)(68 - 32)
What is the equation to convert Kelvin (K) into oC?
K = oC + 273.15
0 K (0 Kelvin) is the _______ possible temperature that can exist.
Setup the equation to convert 25oC into K.
25oC + 273 = 298 K.
In temperature changes, Heat Capacity is often called what?
The amount of heat needed to raise the temperature of exactly one gram of any substance by 1oC is called what?
Specific heat, or specific heat capacity.
When dealing with an equation to calculate the specific heat capacity, what symbol is commonly used to represent specific heat?
What is the equation to calculate the amount of heat needed to increase or decrease the temperature by a specific amount?
heat needed = C x mass x change in temperature
What is the equation to calculate a change in temperature?
ΔT = Tf - Ti
Where Tf = final temperature, and Ti = initial temperature.