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CHM130 study guide for final exam. Instructor: Ken Costello

1. Stone tool technology depended on finding rocks with glass-like properties. Obsidian was one of them.

2. When a clay pot is fired, a chemical change occurs which makes it waterproof and harder.

3. Food stored will spoil unless something inhibits the growth of bacteria and mold.

Building Blocks Forces & Energy Mathematics

What are the two primary elements that make up glass?

Silicon and oxygen

What kind of bond is there between these elements?

Covalent

Obsidian density is 2.4 g/cm3. The mass of an obsidian arrow head is 7.2 grams. What is its volume?A. 7.2 cm3

B. 3 cm3

C. 3 gramsD. 3 times

When clay is fired, what compound is driven off?

Water

Firing requires high temperatures. Name three fuels that ancient people used. (3pts)

Animal fatWoodAnimal Dung(anything flammable)

Ceramic instructions says fire at 1000°C. Your kiln temp gauge is in Fahrenheit, what do you set it to? (F=C*9/5+32)A. 9032 °FB. 243°F C. 587 °FD. 1832 °F

Bacteria absorb dissolved nutrients to survive. What compound do you eliminate to stop this process?

Water

How does salt pull water out of food?

Salt has + & - charges that pull on water

Or water has + & - charges that pull on the salt.

Wine is preserved with 120mg per liter sulfur dioxide (SO2). Your doctor says you can have 90 mg. How much can you drink?

A. 750 mL

B. 0.75 mL

C. 1333 cc

D. 1.33 L

B

D

A

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6. The Periodic Table of the Elements organizes elements in rows and columns.

7. These seven non-metals combine to make poisonous gases. Knowing which gases are lighter or heavier than air could save your life.

5. The Periodic Table of the Elements organizes elements in rows and columns.

Which two columns have elements that combine with each other the most aggressively?

1A and 7A

Or 1 and 17

What kind of bond is there between these elements?

Ionic

Electronegativity measures attraction to electrons: F=4.0, Na=0.93, K=0.82, Cl=3.16. Which has stronger bond, NaF or KCl?

NaF

Name this compound P3O4 (2pts)

Triphosphorus tetraoxide

Or triphosphorus tetroxide.

Air inside a hot air balloon is a mixture of nitrogen, oxygen, carbon dioxide, water vapor, and carbon monoxide. What force is causing the hot air balloon to rise?

Gravity.

To compare densities of gases, compare molecular weight. Which is more dense, nitrogen monoxide or carbon monoxide?

Nitrogen monoxide.

If sodium had been the building block, find an alternative with similar properties.

One of these: Potassium (K), Lithium (Li), Rubidium (Rb), or any from Group 1A. [Letters are good. Name not needed]

Which column in the Periodic Table has elements that pull the hardest on electrons?

7A

Or 17

How many times heavier is sulfur compared with oxygen?

Twice

Looking at the atomic weights, what element needs to fuse with oxygen to make silicon?

Carbon.

Millions of degrees are needed for elements to fuse together. Why?

To overcome electron to electron & proton to proton repulsions

The remains of a supernova are neutrons at density of 454 billion g/cm3. A teaspoon (5 cc) of this

weighs how many lbs.?

A. 17 battleships (5 billion lbs)

B. 9 locomotives (1 million lbs)

C. 454 billion lbs.

D. 1 million grams.

4. Supernovas are responsible for creating the 100+ elements we know of.

A

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8. Groups 1A, & 2A are called alkali metals & alkali Earth metals. The name “alkali” is Arabic for the saltwort plant.

9. Water absorbs heat well, which is why it’s used in car radiators.

10. One food calorie is actually 1000 calories. So a 1000 calorie milkshake is actually 1 million calories (1,000 kcal).

Building Blocks Forces & Energy MathematicsThe ashes of the Al Kali plant contain hydroxides (OH-) of groups 1A & 1B. These neutralize acids (H+) to make what?

Water

Lab students are warned about adding acids (H+) to bases (OH-). These neutralize each other, so what’s the problem?

A lot of heat is produced.

(optional) It may boil and splash.

One mole of Ca(OH)2 is mixed with 2 moles of H2SO4. How many moles of water is produced?

2 moles

Draw a water molecule. Label atoms and show where partial charges are..

What causes water to have a higher than expected boiling point?

The + & - ends of water pull on each other.

How many calories is needed to raise 53 gallons (200 Liters) of water in a water heater from 20°C (room temp) to 70°C?

A. 10,000 calories

B. 100,000 calories

C. 10,000,000 calories

When sugar is “burnt” for energy, it makes the same two building blocks that built it, which are…?

Carbon dioxide and water.

Cellulose is made of chains of glucose. Why don’t we get calories (energy) from eating cellulose?

We don’t have the enzymes to break up the cellulose into glucose.

A (1000 kcal) milkshake can run a 40 watt bulb for how many hours? (note: 1 calorie produces 4 watts for 1 sec.)

A. 28 hours

B. 0.03 hours

C. 40 hours

D. 69 hoursWhat are those 6 elements? 6pts

Hydrogen

Carbon

Oxygen

Nitrogen

Sulfur

Phosphorus

In living things, energy from sugar makes ATP which provides energy for reactions. How many phosphate groups are in ATP?

3

Energy from ribose comes from this reaction. Balance it.

__C5H10O5 + _5O2

_5CO2 + _5H2O

11.Living things are built from 6 elements with a few metals needed for certain proteins.

C

A

OHH +

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12. Supernova explosions spread elements all over the universe. Gravity collects elements to form new stars and solar systems.

14. In chemical reactions elements rearrange themselves.

13. Atoms are too small to count, so chemistry resorts to indirect ways of counting. I call it the art of counting without counting.

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Helium is 2nd most abundant element in universe, yet very little is on Earth. Why? (2pts)

Being light it is lost to space. Being inert, it doesn’t bond.

What would a helium balloon do if released on surface of the moon? Why? (2 pts)

It would fall.

Gravity is the reason(optional: there is no air to lift it)

Abundance is given in %, ppm, or ppb. Write these as fractions. (3pts)

1/100,

1/1,000,000

1/1,000,000,000

A solution of sodium sulfide [Na2S] and cadmium nitrate [Cd(NO3)2] are mixed to make yellow precipitate of cadmium sulfide [CdS] and aqueous sodium nitrate. What kind of reaction is this?

Double replacement

Water pulls on compounds that have a charge. Sometimes this dissolves them. When one of the compounds to the left is not soluble in water?

CdS (or cadmium sulfide)

If 144.5 grams of cadmium sulfide precipitate was produced. How many atoms of cadmium is in the precipitate?

A. 1 mole

B. 112.4

C. 6x1023

D. 1.28 moles

Making trillions of molecules of CO2 is easy: burn coal. Why is making one molecule hard?

They are too small to see or handle.

Gas pressure depends on the speed of the gas molecules. How does temperature affect the speed?Speed is proportional to temperature(or temperature goes up, speed goes up.)

The ideal gas law is PV=nRT. The symbols stand for what? 5ptsP=pressureV=volumen=molesR=0.0821T=Temperature

What are the formulas for ethanol, hydrochloric acid, and chloroform? (3 pts)

CH3CH2OH or C2H6O

HCl

CHCl3

Chloroform is mostly non-polar and will not mix with the polar ethanol/hydrochloric acid mixture. What does polar mean?

One end of molecule is +, other end -.

Spot test recipe calls for1 mole acetaldehyde.How many grams ofacetaldehyde is that?

A. 44 grams

B. 16 grams

C. 32 grams

D. 29 grams

15. Crime labs use color tests (spot tests) to screen for drugs. One common one is the Duquenois-Levine Test for testing marijuana. Chemicals needed are acetaldehyde, ethanol, vanillin, hydrochloric acid and chloroform.

O

Below is the structure of the fungicide he died from. If someone burned this fungicide, could hydrogen cyanide [HCN] and hydrochloric acid [HCl] be products of this burning (assume hydrogen could come from moisture in the air)?

Yes.

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17. String theory tries to unify all forces and all matter. Even though it requires 11 dimensions, the math does explain all forces and all known particles.

18. The Internet is full of hoaxes and myths. Many relate to chemistry. Claim: A golfer who had a habit of chewing on his golf tee died after playing 4 rounds of golf. He died from ingesting fungicide sprayed on the grass by chewing on the golf tee.

Status: TRUE

Hoax & Myth Busters.

19. List 3 myth-urban legend-hoax buster Websites:3pts www.snopes.com www.hoaxbusters.ciac.org www.greenfacts.org

Building Blocks Forces & Energy Mathematics

What does the string theory say is the smallest building block that makes everything in the universe?

Extremely small strings of energy

What are the 4 forces of the universe? 5pts

GravityElectromagnetic ForceStrong Nuclear ForceWeak Nuclear Force

And which one holds the nucleus of atoms together?Electromagnetic force.

Electromagnetic force is said to be 1036 times stronger than gravitational force. How many times would you have to say billion to equal this?

4 times

Carbon & nitrogen are bonded in the molecule by sharing 3 electrons each. Nitrogen has one pair of electrons not involved. Which would be attracted to this pair of electrons, acid [H+} or base [OH-]?

A liter of diet soda has 500 mg of aspartame. 1/10 of the aspartame will decompose into methanol. EPA set daily dose of 0.5 mg per kg body weight for methanol. I weigh 100 kg. What is my limit for methanol?50 mg.If I drink 2 liters of diet soda, do I go over that limit?

Yes.

The mineral in teeth is apatite with formula: Ca?(PO4)3OHHow many Calciums are needed to make this compound neutral?

Five

Acids attack the OH in apatite turning the OH to H2O. The apatite is left with +1 charge. How will water respond?

Negative end of water will be attracted and pull apatite apart

Prescription fluoride toothpaste is 0.4% wt/vol fluoride. How many grams of fluoride in 1 liter (about 10 tubes)?

4 grams.

Will it kill you if lethal dose is 5 grams? No.

16. Fluoride (F-) in high doses is lethal, in low doses it is used to fight tooth decay.

C N

… … .. unpaired

H+