The Testing Center is in the center of the campus in building LC (shown in yellow).  It's on the second floor.  You can park in the northern parking lot or the west parking lot. 

Their hours are 8am to 6pm Monday through Thursday and then 8am to 4pm on Friday.  You should get there at least 2 hours before they close because you have a two hour time limit to do the mid-term.  You shouldn't need that much time.

There are some calculations on the exam.  The Testing Center will supply a calculator.

The Testing Center has some rules for using their center.   Below is part of their instructions.  Here is the link to that page.

All testing requires valid state issued Photo ID or PC Student ID
Please visit your Maricopa Student Account at my.maricopa.edu prior to testing.
(First and Last Name(s) on ID presented MUST Match Exactly the First and Last Name(s) in Student Account) before you can test.   Thank you

When you arrive at the Testing Center:

• Pull a ticket number and have a seat in the hallway corridor.
• When ticket number appears in display case, above lockers, enter Room 206.

Below is more information given for online students who take tests on-campus. To see more information and the specific page, visit this page.

Information for Students:

• All tests are administered on a walk-in and first-seat available basis.  
• No appointment is necessary, but plan adequate time to complete an exam.
• Bring a current valid photo ID with your instructor's first and last name.
• All course exams are administered precisely according to faculty instructions. Possible reasons for test denial are; arriving with less than 30 minutes prior to closing, no picture ID, test not here, and testing deadline has passed.
• The Testing Center is located in the LC builiding, second floor.  When you arrive, please pull a number so that we can better serve you. Do not enter room LC-206 until your number is displayed on the screen.

It is your responsibility to read and understand the following test policies and procedures before you begin your test:

• No children are allowed in the test room or left unattended elsewhere.
• It is your responsibilty to communicate with your instructor regarding items allowed during the test such as a calculator, notes, textbook, restroom break, etc.
• You may not begin the exam, then leave and come back at a later time to finish your test.
• Ask the Test Proctor what your time limit is before you receive your test.
• Once you sit down – it counts as you starting your test.
• Do not leave the Testing Room without permission of the Test Proctor.
• Lockers – All materials including Cell Phones and electronic devices must be secured in a locker.  We are not responsible for lost or stolen personal items.
• If you have a Cell Phone with you in the Testing Room or any unauthorized item or suspected of cheating by others-your test will be collected immediately, voided, and the matter will be referred to your Instructor and Dean of Academic Affairs. 

On the exam, some of the cells above will be empty. You will fill those in. In the "Examples" column, you will only need to give one.

Four classifications of matter can be determined by asking 3 questions. Those four classifications are heterogeneous mixture, homogeneous mixture, element, or compound.

Using the questions in the above table, determine the classification of the following items: (Choices: heterogeneous mixture, homogeneous mixtures, element, or compound.)

Root beer float, sodium chloride (table salt), aluminum foil, grape juice, toothpaste, raisin bread, quartz, syrup, Pepsi on ice, filtered orange juice, orange juice with pulp, air, pure water, muddy water, ice made from pure water, plain paper, Christmas wrapping paper, 24 karat (carat) gold ring, 14 karat gold ring, iron nail, rusty iron nail, glass in a window, urine, NaHCO₃ (baking soda).  (These are answered at bottom of this study guide. First see if you can figure them out).

Physical and Chemical Properties

Physical properties are properties of the substance itself.  Physical properties do not mention how the element or compound reacts with another substance. That belongs to chemical properties.  

Some physical properties are color, form (gas/liquid/solid), odor, melting point, boiling point, malleable (easy to bend or reshape), crystalline, amorphous (no crystal structure), density, electrical conductivity (good conductor or insulator), index of refraction (how much it bends light), and more. Even without using equipment, you can identify the physical properties of substances such as color, form, taste, and odor.  However, taste is not a good idea for checking most chemicals.

Physical properties of a natural diamond:
Color: Can be most any color.
Density: 3.5-3.53 g/cm3
Index of Refraction: 2.418
Hardness:  10 on the Mohs scale

Chemical properties describe how a substance will react with other substances. For example, saying something is flammable is saying it will react with oxygen. So being flammable is a chemical property.

"Strong acids dissolve metals".  This is a general statement of a chemical property for strong acids.  Notice that it is mentioning a different substance (metals in this case).  Chemical properties tell you how a substance will react with another substance.

"Sodium bicarbonate neutralizes acids."   This is a chemical property statement for sodium bicarbonate.  

"Citric acid is incompatible with alkaline carbonates and bicarbonate."   A statement that uses the word "incompatible" is stating a chemical property.   In other words, it is saying that this substance will react with these other substances.  It's incompatible because citric acid will no longer stay citric acid if in contact with the other substances mentioned.

On the test, match the chemical property with the correct substance (Below are the correct matches. On the midterm exam, they will be scrambled.  Some of the substances might be different, too.)

A physical change is when the physical properties of a substance have changed, but the make up (formula) of the substance does not change. For example, water changing to ice is a physical change. The physical properties of ice (such as density, hardness, index of refraction) are different than those of water. However, the formula for ice (H2O) is the same as for water (H2O). So there was no chemical change only a physical change.

Physical changes are usually easily reversible.

A chemical change means the substance changes into another substance. In other words, its chemical formula changes. If a substance decomposes, that is a chemical change. If a substance reacts with another substance, that's a chemical change.  For example, when the Statue of Liberty was erected in 1886, the copper metal was copper in color.   However, by 1900, it had turned a turquoise color.   The copper underwent a chemical change, going from metallic copper to a mixture of copper oxides, copper carbonates, copper sulfates, and copper chlorides due to exposure to various chemicals in the air and rain.

Chemical changes are not as easily reversible as physical changes. That's why we worry more about unplanned chemical changes.

Physical Change Desired: Air Conditioning

The freon in air conditioners (home or car) changes from gas to a liquid and back to a gas, which then repeats. This is a physical change because the freon does not change its chemical makeup, just its state (liquid versus gas).

If freon leaks out, ultraviolet light in sunlight will decompose the freon. One decomposition product is chlorine gas. Is decomposition a chemical or physical change?

Chemical Change Desired: Combustion for engines and stoves.

Whether it is combustion in the engine of a car or on the stove, combustion requires a chemical change. In these cases, it is a hydrocarbon (compound made from carbon and hydrogen atoms) that is combining with oxygen to form carbon dioxide and water. Energy is released and we get heat to build up pressure in the engine's cylinders or heat to cook our food. A chemical change is desired in this situation because that's what will produce heat.

If liquid gasoline enters the cylinder and simply turns to vapor but does not burn, is that a chemical or physical change?

Physical Change Desired: Lighting

Most lighting depends on a physical change. The traditional light bulb has a filament that heats up and glows. That is a physical change. When the electricity is off, the filament cools down to its original physical state. However, if the bulb is cracked and air is introduced, the oxygen in the air reacts with the tungsten filament which then undergoes a chemical change as it becomes tungsten oxide, which is brittle. So the filament breaks and the light bulb stops working. In this situation, we don't want a chemical change. So the bulbs are engineered to prevent chemical changes.

Candles produce light. Is that because of a physical change, chemical change or both?

LED lights don't have glass enclosures to keep out oxygen. So the material that makes up LED is resistant to oxygen. Is that a physical property or chemical property?

Chemical Change Not Desired: Food and Medicine Expiration dates

Why do food and medicine have expiration dates? It's because there is a slow chemical process going on. After the expiration date, a significant portion of the ingredients in medicine may have undergone chemical change and converted to some other chemical. Food has the same problem. Protein, fat, sugar, starches, and vitamins that make up food will chemically break down or react with other ingredients in the food or air. Bacteria will also alter the chemical makeup. So in these situations, spoilage or degradation is occurring because of chemical changes. Preservation of food and medicine is designed to slow down or prevent chemical change.

Chocolate is a food. If it melts, is that a physical change or chemical change?

Does cooking of food cause a physical change or chemical change?

A new bottle of Aspirin doesn't have much of a smell. However, over time it will smell like vinegar. Do you think a physical change or chemical change took place?

The Metric system is based on the Earth, water, and 10 fingers. These items we all have access to, so the metric measurements can be recreated by anyone on Earth.

The meter is the distance from the north pole to the equator divided by 10 million. This distance is a little longer than a yard. So we now have a distance measurement
A box that is one tenth of a meter (a decimeter) on all sides is called the liter. So we now have a volume measurement.
A liter of water is assigned the mass of one kilogram (1000 grams). So we now have a mass measurement.
The prefixes of the metric system are based on ten (because we have 10 fingers).

Use the body to know these metric distances
One meter:  Distance from neck to tip of fingers.
One meter:  Distance between steps in a fast walk or when pacing out distances.
One decimeter=(0.1 meter):  Width of the hand.
One centimeter=(0.01 meter):  Width of a fingernail.
One millimeter=(0.001 meter):  Thickness of a fingernail.
100 micrometers=0.1 millimeters=(0.0001 meter):  The smallest object your eyes can see, which would be an object that is the width of a human hair.

Use these average volumes related to the body to know metric volumes.

One liter:  Volume of stomach when it feels full.
Half a liter:  Volume of cupped hands.
Half a liter:  Volume of air in normal breath.
5 liters:   Volume of human head
5 liters:  Volume of blood in body
5 milliliters (0.001 liters):  Volume of eyeball
90 femtoliters (10^-15 liters):  Volume of one red blood cell
3 liters:  Volume of water ingested per day
1.5 liters:  Volume of urine output per day

Use these average masses related to the body to know metric masses.

8 grams:  Mass of eyeball
65 grams:  Mass of tongue
300 grams: Mass of heart
1.5 kilograms:  Mass of brain
5 kilograms:  Mass of head
100 kilograms (100,000 grams):   5% of American males are above this weight
87 kilograms (87,000 grams):   Average weight of American male
3 kilograms:  The mass one human hair can hold without breaking.
6,000 kilograms:  If the hair on your head was woven into a rope, it could support 6,000 kilograms (the mass of about 3 automobiles.)

Convert the following metric volumes: (On the test, the amounts will be somewhat different)

3000 milliliters to liters:
5 liters to milliliters:
half liter to milliliters:
1.5 liters to milliliters:
One trillion femtoliters to milliliters:

Convert the following metric distances:  (On the test, the amounts will be different)

2.35 meters into centimeters:
2.35 meters into millimeters:
1 centimeter into millimeters:
2 decimeters into meters:
0.35 meters into decimeter:
505 micrometers into meters:

10.0 mL x 19.3 g = 193 g
           1 mL

50.0 g x  1 mL   = 2.59 mL
         19.3 g

Here we see milliliters (mL) of gold being converted to grams (g) of gold by using the density of gold (19.3 grams per mL).   The mL cancel out leaving just grams.

In the second calculation, we see grams of gold being converted to milliliters of gold by using the density of gold inverted. grams is on the bottom so that they will cancel the starting grams.

On the midterm exam, there will be some dimensional analysis problems that are set up that you solve.  Some will be fully setup (like above) and some will be partially set up like below. 

Driving 424 miles in a car that gets 22.0 miles per gallon will take how many liters of gas? The dimensional analysis is set up below to solve that, but you need to write the correct dimensions (measurement units) in their proper place.   B1 shows that miles is the starting units.  The information of 22.0 miles per gallon is inverted so that miles is in the denominator and cancels the miles in B1.   At column E we have volume in gallons, but the question wants it in liters.  So columns G and H convert the gallons to liters.    So you would write "miles" in E2, "liters" in H1, and "gallons" in H2.   Do the arithmetic to find the quantity of liters that is written in S1. On the exam, some units will be left out for you to insert into the proper cell.

The top temperature is the boiling point of water. 50°C (122°F) is the hottest day on record in Phoenix, Arizona. 98.6°F (37°C) is the temperature of the body. 68°F (20°C) is considered room temperature.  Most glassware for labs are calibrated to be most accurate at 20°C.    32°F (0°C) is where water coexists as liquid water and ice (freezing point). 0°F (-18°C) is temperature of a mixture of snow (or ice) and salt.

Notice from freezing to boiling is 180 degrees on the Fahrenheit scale and 100 degree on the Celsius scale.   That's why the fraction 180/100 or 9/5 shows up in the formulas to convert these temperatures.    Also, notice the freezing point of water is 0°C but 32° on the Fahrenheit scale.  So they don't both start at zero.  That's why 32 degrees is subtracted from Fahrenheit temperatures before they are converted to Celsius.  

To go Fahrenheit to Celsius, subtract 32 first, then multiply by 5/9 to make the number of degrees fewer.  That's because the scale of Celsius uses fewer degrees (steps) to go from freezing to boiling.    To go from Celsius to Fahrenheit, multiply by 9/5 to get a higher number.  Then add 32 because Fahrenheit is 32 degrees when Celsius is 0 degrees.  

On the test, this chart will be there, but you will have different degrees to convert. No formula for conversion will be given.  Just use the logic given above.

Absolute Zero: 

The Kelvin scale, named after Lord Kelvin who proposed it, sets zero at absolute zero, which is the temperature where all atoms stop moving, spinning, or vibrating. Electrons & nuclei, however, continue to move. 

Notice these low temperature markers. Dry ice is at -108°F (-78°C/195K). Other gases in the air (oxygen, nitrogen) start turning to liquid around 300°F below zero.  Everything is solid at Absolute Zero.

Conversion to Kelvin is fairly straightforward.  Add 273.15 degrees to the Celsius temperature.  It's OK to add just "273"  if your Celsius degrees have no decimal places.

Using the portion of the Periodic Table on the left, answer the below questions:

One mole of helium atoms weighs how many grams?
One mole of oxygen atoms weighs how many grams?
One mole of oxygen molecules (O2) weighs many grams?
One mole of CO2 (carbon dioxide) molecules weighs many grams?
What element has the atomic number of 33?
How many protons does an atom of aluminum have?
How many electrons does a neutral atom of boron have?
Why are some of these elements shown with a pinkish background?
What two elements are most chemically similar to chlorine?
Above fluorine (F) are the letters "VIIB".  What is significance of the Roman numeral VII?
Fluorine atoms have the average atomic mass of 18.99840.  Therefore, how many neutrons do most fluorine atoms have?
If the nucleus of a silicon atom were to gain a proton, what element would it become?
If the nucleus of a carbon atom were to fuse with the nucleus of helium, what element would they become?
A mole of krypton gas is how many krypton atoms?
20.1797 grams of neon gas is how many moles of neon gas?
50 grams of carbon is how many moles of carbon?

Write the formula for these binary & polyatomic ionic compounds.

a) Potassium chloride
b) Titanium (II) oxide
c) Calcium carbonate
d) Sodium bicarbonate
e) Iron (II) sulfate
f) Calcium sulfate
g) Ammonium chloride 

Write the formula for these acids:

Carbonic acid:
Sulfurous acid
Acetic acid

Give the written name of these binary & polyatomic ionic compounds.

a) NaCl
b) TiO₂
c) NaNO₃
d) KNO₃
e) NaCN
f) NaClO
g) KClO₄
h) Na₂CO₃

Chemical energy is a type of potential energy. It's similar to raising objects against gravity except instead of moving objects against the attraction of gravity, it is moving objects against the attraction of plus and minus charges. To illustrate this, let's look at the simplest of elements, hydrogen....

The hydrogen atom consists of one proton (+) and one electron (-). The proton sits in the center (nucleus) of the atom. The diagram shows the electron as a particle orbiting the nucleus. If an electron is moved farther away from the proton, it takes energy because they are attracted to each other (like gravity). The farther away the electron has been moved away from the proton, the more energy it takes, and the more potential energy stored in the electron. When the electron drops back closer to the proton, it will convert that potential energy to light energy. The light energy can be in the form of infrared, visible, ultraviolet, or even X-ray light.

Helium has two protons.  Would you think it takes more or less energy to pull an electron away from the helium nucleus compared to a hydrogen nucleus?

Would an electron that has been pulled away from a helium nucleus have more or less potential energy than an electron that was pulled away from an hydrogen nucleus?

Horsepower is work energy per minute.  It came from the fact that one horse using a pulley could lift 330 lbs 100 feet in one minute. So that's 330lbs x 100 ft / 1 min. Or 33,000 ft·lbs/min. In other words, the pounds (lbs) times the feet divided by the minutes will come out to 33000 if one horsepower. We need an elevator to lift 1550 lbs. If this elevator gets 1550 lbs up to the 20th floor (200. feet) within half a minute, what horsepower motor is it using?  Dimensional analysis uses the trick of letting the dimensions guide how to do the problem.  Since horsepower has the units of ft·lbs/min, then it says to multiply the feet by the pounds, then divide by the minutes.  On the exam, the values will be different and the problem won't be totally set up.

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